i2c-core-base.c 98.6 KB
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/* i2c-core.c - a device driver for the iic-bus interface		     */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-99 Simon G. Vogl

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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    GNU General Public License for more details.			     */
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/* ------------------------------------------------------------------------- */

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/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
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   All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
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   SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
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   Jean Delvare <jdelvare@suse.de>
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   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
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   Michael Lawnick <michael.lawnick.ext@nsn.com>
   OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
   (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
   (c) 2013  Wolfram Sang <wsa@the-dreams.de>
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   I2C ACPI code Copyright (C) 2014 Intel Corp
   Author: Lan Tianyu <tianyu.lan@intel.com>
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 */
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#define pr_fmt(fmt) "i2c-core: " fmt

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#include <dt-bindings/i2c/i2c.h>
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#include <linux/uaccess.h>
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#include <linux/acpi.h>
#include <linux/clk/clk-conf.h>
#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/gpio.h>
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#include <linux/hardirq.h>
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#include <linux/i2c.h>
#include <linux/idr.h>
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#include <linux/init.h>
#include <linux/irqflags.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of_device.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/pm_domain.h>
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#include <linux/pm_runtime.h>
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#include <linux/pm_wakeirq.h>
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#include <linux/property.h>
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#include <linux/rwsem.h>
#include <linux/slab.h>
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#include "i2c-core.h"

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#define CREATE_TRACE_POINTS
#include <trace/events/i2c.h>
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#define I2C_ADDR_OFFSET_TEN_BIT	0xa000
#define I2C_ADDR_OFFSET_SLAVE	0x1000

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#define I2C_ADDR_7BITS_MAX	0x77
#define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)

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/* core_lock protects i2c_adapter_idr, and guarantees
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   that device detection, deletion of detected devices, and attach_adapter
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   calls are serialized */
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static DEFINE_MUTEX(core_lock);
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static DEFINE_IDR(i2c_adapter_idr);

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static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
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static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
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static bool is_registered;
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int i2c_transfer_trace_reg(void)
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{
	static_key_slow_inc(&i2c_trace_msg);
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	return 0;
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}

void i2c_transfer_trace_unreg(void)
{
	static_key_slow_dec(&i2c_trace_msg);
}

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#if defined(CONFIG_ACPI)
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struct i2c_acpi_handler_data {
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	struct acpi_connection_info info;
	struct i2c_adapter *adapter;
};

struct gsb_buffer {
	u8	status;
	u8	len;
	union {
		u16	wdata;
		u8	bdata;
		u8	data[0];
	};
} __packed;

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struct i2c_acpi_lookup {
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	struct i2c_board_info *info;
	acpi_handle adapter_handle;
	acpi_handle device_handle;
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	acpi_handle search_handle;
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	int n;
	int index;
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	u32 speed;
	u32 min_speed;
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};
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static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
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{
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	struct i2c_acpi_lookup *lookup = data;
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	struct i2c_board_info *info = lookup->info;
	struct acpi_resource_i2c_serialbus *sb;
	acpi_status status;
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	if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
		return 1;

	sb = &ares->data.i2c_serial_bus;
	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
		return 1;

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	if (lookup->index != -1 && lookup->n++ != lookup->index)
		return 1;

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	status = acpi_get_handle(lookup->device_handle,
				 sb->resource_source.string_ptr,
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				 &lookup->adapter_handle);
	if (!ACPI_SUCCESS(status))
		return 1;

	info->addr = sb->slave_address;
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	lookup->speed = sb->connection_speed;
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	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
		info->flags |= I2C_CLIENT_TEN;
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	return 1;
}

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static int i2c_acpi_do_lookup(struct acpi_device *adev,
			      struct i2c_acpi_lookup *lookup)
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{
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	struct i2c_board_info *info = lookup->info;
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	struct list_head resource_list;
	int ret;

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	if (acpi_bus_get_status(adev) || !adev->status.present ||
	    acpi_device_enumerated(adev))
		return -EINVAL;
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	memset(info, 0, sizeof(*info));
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	lookup->device_handle = acpi_device_handle(adev);
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	/* Look up for I2cSerialBus resource */
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	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list,
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				     i2c_acpi_fill_info, lookup);
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	acpi_dev_free_resource_list(&resource_list);

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	if (ret < 0 || !info->addr)
		return -EINVAL;

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	return 0;
}

static int i2c_acpi_get_info(struct acpi_device *adev,
			     struct i2c_board_info *info,
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			     struct i2c_adapter *adapter,
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			     acpi_handle *adapter_handle)
{
	struct list_head resource_list;
	struct resource_entry *entry;
	struct i2c_acpi_lookup lookup;
	int ret;

	memset(&lookup, 0, sizeof(lookup));
	lookup.info = info;
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	lookup.index = -1;
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	ret = i2c_acpi_do_lookup(adev, &lookup);
	if (ret)
		return ret;

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	if (adapter) {
		/* The adapter must match the one in I2cSerialBus() connector */
		if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
			return -ENODEV;
	} else {
		struct acpi_device *adapter_adev;

		/* The adapter must be present */
		if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
			return -ENODEV;
		if (acpi_bus_get_status(adapter_adev) ||
		    !adapter_adev->status.present)
			return -ENODEV;
	}

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	info->fwnode = acpi_fwnode_handle(adev);
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	if (adapter_handle)
		*adapter_handle = lookup.adapter_handle;
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	/* Then fill IRQ number if any */
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	INIT_LIST_HEAD(&resource_list);
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	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
	if (ret < 0)
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		return -EINVAL;
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	resource_list_for_each_entry(entry, &resource_list) {
		if (resource_type(entry->res) == IORESOURCE_IRQ) {
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			info->irq = entry->res->start;
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			break;
		}
	}

	acpi_dev_free_resource_list(&resource_list);

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	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
			  sizeof(info->type));
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	return 0;
}

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static void i2c_acpi_register_device(struct i2c_adapter *adapter,
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				     struct acpi_device *adev,
				     struct i2c_board_info *info)
{
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	adev->power.flags.ignore_parent = true;
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	acpi_device_set_enumerated(adev);

	if (!i2c_new_device(adapter, info)) {
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		adev->power.flags.ignore_parent = false;
		dev_err(&adapter->dev,
			"failed to add I2C device %s from ACPI\n",
			dev_name(&adev->dev));
	}
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}

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static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
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				       void *data, void **return_value)
{
	struct i2c_adapter *adapter = data;
	struct acpi_device *adev;
	struct i2c_board_info info;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;

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	if (i2c_acpi_get_info(adev, &info, adapter, NULL))
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		return AE_OK;

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	i2c_acpi_register_device(adapter, adev, &info);
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	return AE_OK;
}

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#define I2C_ACPI_MAX_SCAN_DEPTH 32
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/**
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 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
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 * @adap: pointer to adapter
 *
 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 * namespace. When a device is found it will be added to the Linux device
 * model and bound to the corresponding ACPI handle.
 */
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static void i2c_acpi_register_devices(struct i2c_adapter *adap)
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{
	acpi_status status;

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	if (!has_acpi_companion(&adap->dev))
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		return;

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	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
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				     I2C_ACPI_MAX_SCAN_DEPTH,
				     i2c_acpi_add_device, NULL,
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				     adap, NULL);
	if (ACPI_FAILURE(status))
		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
}

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static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
					   void *data, void **return_value)
{
	struct i2c_acpi_lookup *lookup = data;
	struct acpi_device *adev;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;

	if (i2c_acpi_do_lookup(adev, lookup))
		return AE_OK;

	if (lookup->search_handle != lookup->adapter_handle)
		return AE_OK;

	if (lookup->speed <= lookup->min_speed)
		lookup->min_speed = lookup->speed;

	return AE_OK;
}

/**
 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
 * @dev: The device owning the bus
 *
 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
 * devices connected to this bus and use the speed of slowest device.
 *
 * Returns the speed in Hz or zero
 */
u32 i2c_acpi_find_bus_speed(struct device *dev)
{
	struct i2c_acpi_lookup lookup;
	struct i2c_board_info dummy;
	acpi_status status;

	if (!has_acpi_companion(dev))
		return 0;

	memset(&lookup, 0, sizeof(lookup));
	lookup.search_handle = ACPI_HANDLE(dev);
	lookup.min_speed = UINT_MAX;
	lookup.info = &dummy;
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	lookup.index = -1;
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	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
				     I2C_ACPI_MAX_SCAN_DEPTH,
				     i2c_acpi_lookup_speed, NULL,
				     &lookup, NULL);

	if (ACPI_FAILURE(status)) {
		dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
		return 0;
	}

	return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);

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static int i2c_acpi_match_adapter(struct device *dev, void *data)
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{
	struct i2c_adapter *adapter = i2c_verify_adapter(dev);

	if (!adapter)
		return 0;

	return ACPI_HANDLE(dev) == (acpi_handle)data;
}

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static int i2c_acpi_match_device(struct device *dev, void *data)
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{
	return ACPI_COMPANION(dev) == data;
}

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static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
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{
	struct device *dev;

	dev = bus_find_device(&i2c_bus_type, NULL, handle,
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			      i2c_acpi_match_adapter);
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	return dev ? i2c_verify_adapter(dev) : NULL;
}

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static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
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{
	struct device *dev;

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	dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_match_device);
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	return dev ? i2c_verify_client(dev) : NULL;
}

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static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
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			   void *arg)
{
	struct acpi_device *adev = arg;
	struct i2c_board_info info;
	acpi_handle adapter_handle;
	struct i2c_adapter *adapter;
	struct i2c_client *client;

	switch (value) {
	case ACPI_RECONFIG_DEVICE_ADD:
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		if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
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			break;

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		adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
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		if (!adapter)
			break;

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		i2c_acpi_register_device(adapter, adev, &info);
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		break;
	case ACPI_RECONFIG_DEVICE_REMOVE:
		if (!acpi_device_enumerated(adev))
			break;

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		client = i2c_acpi_find_client_by_adev(adev);
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		if (!client)
			break;

		i2c_unregister_device(client);
		put_device(&client->dev);
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block i2c_acpi_notifier = {
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	.notifier_call = i2c_acpi_notify,
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};
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/**
 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
 * @dev:     Device owning the ACPI resources to get the client from
 * @index:   Index of ACPI resource to get
 * @info:    describes the I2C device; note this is modified (addr gets set)
 * Context: can sleep
 *
 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
 * resources, in that case this function can be used to create an i2c-client
 * for other I2cSerialBus resources in the Current Resource Settings table.
 *
 * Also see i2c_new_device, which this function calls to create the i2c-client.
 *
 * Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
 */
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
				       struct i2c_board_info *info)
{
	struct i2c_acpi_lookup lookup;
	struct i2c_adapter *adapter;
	struct acpi_device *adev;
	LIST_HEAD(resource_list);
	int ret;

	adev = ACPI_COMPANION(dev);
	if (!adev)
		return NULL;

	memset(&lookup, 0, sizeof(lookup));
	lookup.info = info;
	lookup.device_handle = acpi_device_handle(adev);
	lookup.index = index;

	ret = acpi_dev_get_resources(adev, &resource_list,
				     i2c_acpi_fill_info, &lookup);
	acpi_dev_free_resource_list(&resource_list);

	if (ret < 0 || !info->addr)
		return NULL;

	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
	if (!adapter)
		return NULL;

	return i2c_new_device(adapter, info);
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
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#else /* CONFIG_ACPI */
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static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
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extern struct notifier_block i2c_acpi_notifier;
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#endif /* CONFIG_ACPI */

#ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
		u8 cmd, u8 *data, u8 data_len)
{

	struct i2c_msg msgs[2];
	int ret;
	u8 *buffer;

	buffer = kzalloc(data_len, GFP_KERNEL);
	if (!buffer)
		return AE_NO_MEMORY;

	msgs[0].addr = client->addr;
	msgs[0].flags = client->flags;
	msgs[0].len = 1;
	msgs[0].buf = &cmd;

	msgs[1].addr = client->addr;
	msgs[1].flags = client->flags | I2C_M_RD;
	msgs[1].len = data_len;
	msgs[1].buf = buffer;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
		dev_err(&client->adapter->dev, "i2c read failed\n");
	else
		memcpy(data, buffer, data_len);

	kfree(buffer);
	return ret;
}

static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
		u8 cmd, u8 *data, u8 data_len)
{

	struct i2c_msg msgs[1];
	u8 *buffer;
	int ret = AE_OK;

	buffer = kzalloc(data_len + 1, GFP_KERNEL);
	if (!buffer)
		return AE_NO_MEMORY;

	buffer[0] = cmd;
	memcpy(buffer + 1, data, data_len);

	msgs[0].addr = client->addr;
	msgs[0].flags = client->flags;
	msgs[0].len = data_len + 1;
	msgs[0].buf = buffer;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
		dev_err(&client->adapter->dev, "i2c write failed\n");

	kfree(buffer);
	return ret;
}

static acpi_status
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i2c_acpi_space_handler(u32 function, acpi_physical_address command,
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			u32 bits, u64 *value64,
			void *handler_context, void *region_context)
{
	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
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	struct i2c_acpi_handler_data *data = handler_context;
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	struct acpi_connection_info *info = &data->info;
	struct acpi_resource_i2c_serialbus *sb;
	struct i2c_adapter *adapter = data->adapter;
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	struct i2c_client *client;
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	struct acpi_resource *ares;
	u32 accessor_type = function >> 16;
	u8 action = function & ACPI_IO_MASK;
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	acpi_status ret;
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	int status;

	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
	if (ACPI_FAILURE(ret))
		return ret;

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	client = kzalloc(sizeof(*client), GFP_KERNEL);
	if (!client) {
		ret = AE_NO_MEMORY;
		goto err;
	}

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	if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	sb = &ares->data.i2c_serial_bus;
	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
		ret = AE_BAD_PARAMETER;
		goto err;
	}

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	client->adapter = adapter;
	client->addr = sb->slave_address;
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	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
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		client->flags |= I2C_CLIENT_TEN;
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	switch (accessor_type) {
	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
		if (action == ACPI_READ) {
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			status = i2c_smbus_read_byte(client);
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			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
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			status = i2c_smbus_write_byte(client, gsb->bdata);
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		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
		if (action == ACPI_READ) {
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			status = i2c_smbus_read_byte_data(client, command);
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			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
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			status = i2c_smbus_write_byte_data(client, command,
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					gsb->bdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_WORD:
		if (action == ACPI_READ) {
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			status = i2c_smbus_read_word_data(client, command);
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			if (status >= 0) {
				gsb->wdata = status;
				status = 0;
			}
		} else {
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			status = i2c_smbus_write_word_data(client, command,
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					gsb->wdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
		if (action == ACPI_READ) {
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			status = i2c_smbus_read_block_data(client, command,
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					gsb->data);
			if (status >= 0) {
				gsb->len = status;
				status = 0;
			}
		} else {
629
			status = i2c_smbus_write_block_data(client, command,
630 631 632 633 634 635
					gsb->len, gsb->data);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
		if (action == ACPI_READ) {
636
			status = acpi_gsb_i2c_read_bytes(client, command,
637 638 639 640
					gsb->data, info->access_length);
			if (status > 0)
				status = 0;
		} else {
641
			status = acpi_gsb_i2c_write_bytes(client, command,
642 643 644 645 646
					gsb->data, info->access_length);
		}
		break;

	default:
647 648
		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
			 accessor_type, client->addr);
649 650 651 652 653 654 655
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	gsb->status = status;

 err:
656
	kfree(client);
657 658 659 660 661
	ACPI_FREE(ares);
	return ret;
}


662
static int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
663
{
664
	acpi_handle handle;
665
	struct i2c_acpi_handler_data *data;
666 667
	acpi_status status;

668 669 670 671 672
	if (!adapter->dev.parent)
		return -ENODEV;

	handle = ACPI_HANDLE(adapter->dev.parent);

673 674 675
	if (!handle)
		return -ENODEV;

676
	data = kzalloc(sizeof(struct i2c_acpi_handler_data),
677 678 679 680 681 682 683 684 685 686 687 688 689
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->adapter = adapter;
	status = acpi_bus_attach_private_data(handle, (void *)data);
	if (ACPI_FAILURE(status)) {
		kfree(data);
		return -ENOMEM;
	}

	status = acpi_install_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
690
				&i2c_acpi_space_handler,
691 692 693 694 695 696 697 698 699
				NULL,
				data);
	if (ACPI_FAILURE(status)) {
		dev_err(&adapter->dev, "Error installing i2c space handler\n");
		acpi_bus_detach_private_data(handle);
		kfree(data);
		return -ENOMEM;
	}

700
	acpi_walk_dep_device_list(handle);
701 702 703
	return 0;
}

704
static void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
705
{
706
	acpi_handle handle;
707
	struct i2c_acpi_handler_data *data;
708 709
	acpi_status status;

710 711 712 713 714
	if (!adapter->dev.parent)
		return;

	handle = ACPI_HANDLE(adapter->dev.parent);

715 716 717 718 719
	if (!handle)
		return;

	acpi_remove_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
720
				&i2c_acpi_space_handler);
721 722 723 724 725 726 727 728

	status = acpi_bus_get_private_data(handle, (void **)&data);
	if (ACPI_SUCCESS(status))
		kfree(data);

	acpi_bus_detach_private_data(handle);
}
#else /* CONFIG_ACPI_I2C_OPREGION */
729
static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
730 731
{ }

732
static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
733 734 735
{ return 0; }
#endif /* CONFIG_ACPI_I2C_OPREGION */

736 737
/* ------------------------------------------------------------------------- */

738
const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
739 740
						const struct i2c_client *client)
{
741 742 743
	if (!(id && client))
		return NULL;

744 745 746 747 748 749 750
	while (id->name[0]) {
		if (strcmp(client->name, id->name) == 0)
			return id;
		id++;
	}
	return NULL;
}
751
EXPORT_SYMBOL_GPL(i2c_match_id);
752

L
Linus Torvalds 已提交
753 754
static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
755 756 757
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;

D
David Brownell 已提交
758

759
	/* Attempt an OF style match */
760
	if (i2c_of_match_device(drv->of_match_table, client))
761 762
		return 1;

763 764 765 766
	/* Then ACPI style match */
	if (acpi_driver_match_device(dev, drv))
		return 1;

767
	driver = to_i2c_driver(drv);
768 769 770 771

	/* Finally an I2C match */
	if (i2c_match_id(driver->id_table, client))
		return 1;
772

773
	return 0;
L
Linus Torvalds 已提交
774 775
}

776
static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
D
David Brownell 已提交
777
{
778
	struct i2c_client *client = to_i2c_client(dev);
779 780 781 782 783
	int rc;

	rc = acpi_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;
D
David Brownell 已提交
784

785
	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
786 787
}

788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852
/* i2c bus recovery routines */
static int get_scl_gpio_value(struct i2c_adapter *adap)
{
	return gpio_get_value(adap->bus_recovery_info->scl_gpio);
}

static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
{
	gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
}

static int get_sda_gpio_value(struct i2c_adapter *adap)
{
	return gpio_get_value(adap->bus_recovery_info->sda_gpio);
}

static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	struct device *dev = &adap->dev;
	int ret = 0;

	ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
			GPIOF_OUT_INIT_HIGH, "i2c-scl");
	if (ret) {
		dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
		return ret;
	}

	if (bri->get_sda) {
		if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
			/* work without SDA polling */
			dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
					bri->sda_gpio);
			bri->get_sda = NULL;
		}
	}

	return ret;
}

static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;

	if (bri->get_sda)
		gpio_free(bri->sda_gpio);

	gpio_free(bri->scl_gpio);
}

/*
 * We are generating clock pulses. ndelay() determines durating of clk pulses.
 * We will generate clock with rate 100 KHz and so duration of both clock levels
 * is: delay in ns = (10^6 / 100) / 2
 */
#define RECOVERY_NDELAY		5000
#define RECOVERY_CLK_CNT	9

static int i2c_generic_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	int i = 0, val = 1, ret = 0;

	if (bri->prepare_recovery)
853
		bri->prepare_recovery(adap);
854

855 856 857
	bri->set_scl(adap, val);
	ndelay(RECOVERY_NDELAY);

858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880
	/*
	 * By this time SCL is high, as we need to give 9 falling-rising edges
	 */
	while (i++ < RECOVERY_CLK_CNT * 2) {
		if (val) {
			/* Break if SDA is high */
			if (bri->get_sda && bri->get_sda(adap))
					break;
			/* SCL shouldn't be low here */
			if (!bri->get_scl(adap)) {
				dev_err(&adap->dev,
					"SCL is stuck low, exit recovery\n");
				ret = -EBUSY;
				break;
			}
		}

		val = !val;
		bri->set_scl(adap, val);
		ndelay(RECOVERY_NDELAY);
	}

	if (bri->unprepare_recovery)
881
		bri->unprepare_recovery(adap);
882 883 884 885 886 887 888 889

	return ret;
}

int i2c_generic_scl_recovery(struct i2c_adapter *adap)
{
	return i2c_generic_recovery(adap);
}
890
EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
891 892 893 894 895 896 897 898 899 900 901 902 903 904

int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
{
	int ret;

	ret = i2c_get_gpios_for_recovery(adap);
	if (ret)
		return ret;

	ret = i2c_generic_recovery(adap);
	i2c_put_gpios_for_recovery(adap);

	return ret;
}
905
EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
906 907 908 909 910 911 912 913 914

int i2c_recover_bus(struct i2c_adapter *adap)
{
	if (!adap->bus_recovery_info)
		return -EOPNOTSUPP;

	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
	return adap->bus_recovery_info->recover_bus(adap);
}
915
EXPORT_SYMBOL_GPL(i2c_recover_bus);
916

917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957
static void i2c_init_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	char *err_str;

	if (!bri)
		return;

	if (!bri->recover_bus) {
		err_str = "no recover_bus() found";
		goto err;
	}

	/* Generic GPIO recovery */
	if (bri->recover_bus == i2c_generic_gpio_recovery) {
		if (!gpio_is_valid(bri->scl_gpio)) {
			err_str = "invalid SCL gpio";
			goto err;
		}

		if (gpio_is_valid(bri->sda_gpio))
			bri->get_sda = get_sda_gpio_value;
		else
			bri->get_sda = NULL;

		bri->get_scl = get_scl_gpio_value;
		bri->set_scl = set_scl_gpio_value;
	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
		/* Generic SCL recovery */
		if (!bri->set_scl || !bri->get_scl) {
			err_str = "no {get|set}_scl() found";
			goto err;
		}
	}

	return;
 err:
	dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
	adap->bus_recovery_info = NULL;
}

958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
{
	struct i2c_adapter *adap = client->adapter;
	unsigned int irq;

	if (!adap->host_notify_domain)
		return -ENXIO;

	if (client->flags & I2C_CLIENT_TEN)
		return -EINVAL;

	irq = irq_find_mapping(adap->host_notify_domain, client->addr);
	if (!irq)
		irq = irq_create_mapping(adap->host_notify_domain,
					 client->addr);

	return irq > 0 ? irq : -ENXIO;
}

977
static int i2c_device_probe(struct device *dev)
L
Linus Torvalds 已提交
978
{
979 980
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
981
	int status;
D
David Brownell 已提交
982

983 984 985
	if (!client)
		return 0;

986 987 988
	driver = to_i2c_driver(dev->driver);

	if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
989 990
		int irq = -ENOENT;

991 992 993 994
		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
			dev_dbg(dev, "Using Host Notify IRQ\n");
			irq = i2c_smbus_host_notify_to_irq(client);
		} else if (dev->of_node) {
995 996 997 998
			irq = of_irq_get_byname(dev->of_node, "irq");
			if (irq == -EINVAL || irq == -ENODATA)
				irq = of_irq_get(dev->of_node, 0);
		} else if (ACPI_COMPANION(dev)) {
999
			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
1000
		}
1001
		if (irq == -EPROBE_DEFER)
1002
			return irq;
1003

1004 1005
		if (irq < 0)
			irq = 0;
1006 1007 1008 1009

		client->irq = irq;
	}

1010 1011 1012 1013 1014 1015
	/*
	 * An I2C ID table is not mandatory, if and only if, a suitable Device
	 * Tree match table entry is supplied for the probing device.
	 */
	if (!driver->id_table &&
	    !i2c_of_match_device(dev->driver->of_match_table, client))
D
David Brownell 已提交
1016
		return -ENODEV;
1017

1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
	if (client->flags & I2C_CLIENT_WAKE) {
		int wakeirq = -ENOENT;

		if (dev->of_node) {
			wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
			if (wakeirq == -EPROBE_DEFER)
				return wakeirq;
		}

		device_init_wakeup(&client->dev, true);

		if (wakeirq > 0 && wakeirq != client->irq)
			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
		else if (client->irq > 0)
G
Grygorii Strashko 已提交
1032
			status = dev_pm_set_wake_irq(dev, client->irq);
1033 1034 1035 1036
		else
			status = 0;

		if (status)
1037
			dev_warn(&client->dev, "failed to set up wakeup irq\n");
1038 1039
	}

D
David Brownell 已提交
1040
	dev_dbg(dev, "probe\n");
1041

1042 1043
	status = of_clk_set_defaults(dev->of_node, false);
	if (status < 0)
1044
		goto err_clear_wakeup_irq;
1045

1046
	status = dev_pm_domain_attach(&client->dev, true);
1047 1048 1049
	if (status == -EPROBE_DEFER)
		goto err_clear_wakeup_irq;

1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
	/*
	 * When there are no more users of probe(),
	 * rename probe_new to probe.
	 */
	if (driver->probe_new)
		status = driver->probe_new(client);
	else if (driver->probe)
		status = driver->probe(client,
				       i2c_match_id(driver->id_table, client));
	else
		status = -EINVAL;

1062 1063
	if (status)
		goto err_detach_pm_domain;
1064

1065 1066 1067 1068 1069 1070 1071
	return 0;

err_detach_pm_domain:
	dev_pm_domain_detach(&client->dev, true);
err_clear_wakeup_irq:
	dev_pm_clear_wake_irq(&client->dev);
	device_init_wakeup(&client->dev, false);
1072
	return status;
1073
}
L
Linus Torvalds 已提交
1074

1075 1076
static int i2c_device_remove(struct device *dev)
{
1077
	struct i2c_client	*client = i2c_verify_client(dev);
D
David Brownell 已提交
1078
	struct i2c_driver	*driver;
1079
	int status = 0;
D
David Brownell 已提交
1080

1081
	if (!client || !dev->driver)
D
David Brownell 已提交
1082 1083 1084 1085 1086 1087 1088
		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	}
1089

1090
	dev_pm_domain_detach(&client->dev, true);
1091 1092 1093 1094

	dev_pm_clear_wake_irq(&client->dev);
	device_init_wakeup(&client->dev, false);

D
David Brownell 已提交
1095
	return status;
L
Linus Torvalds 已提交
1096 1097
}

1098
static void i2c_device_shutdown(struct device *dev)
L
Linus Torvalds 已提交
1099
{
1100
	struct i2c_client *client = i2c_verify_client(dev);
1101 1102
	struct i2c_driver *driver;

1103
	if (!client || !dev->driver)
1104 1105 1106
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
1107
		driver->shutdown(client);
L
Linus Torvalds 已提交
1108 1109
}

1110 1111 1112 1113 1114
static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

Z
Zhenwen Xu 已提交
1115
static ssize_t
1116
show_name(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
1117
{
1118 1119
	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
D
David Brownell 已提交
1120
}
1121
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
D
David Brownell 已提交
1122

Z
Zhenwen Xu 已提交
1123 1124
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
1125 1126
{
	struct i2c_client *client = to_i2c_client(dev);
1127 1128 1129 1130 1131 1132
	int len;

	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
	if (len != -ENODEV)
		return len;

1133
	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
1134
}
1135 1136 1137 1138
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static struct attribute *i2c_dev_attrs[] = {
	&dev_attr_name.attr,
D
David Brownell 已提交
1139
	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
1140 1141 1142
	&dev_attr_modalias.attr,
	NULL
};
1143
ATTRIBUTE_GROUPS(i2c_dev);
1144

J
Jon Smirl 已提交
1145
struct bus_type i2c_bus_type = {
1146 1147 1148 1149 1150
	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
1151
};
J
Jon Smirl 已提交
1152
EXPORT_SYMBOL_GPL(i2c_bus_type);
1153

1154
struct device_type i2c_client_type = {
1155
	.groups		= i2c_dev_groups,
1156 1157 1158
	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};
1159
EXPORT_SYMBOL_GPL(i2c_client_type);
1160

1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172

/**
 * i2c_verify_client - return parameter as i2c_client, or NULL
 * @dev: device, probably from some driver model iterator
 *
 * When traversing the driver model tree, perhaps using driver model
 * iterators like @device_for_each_child(), you can't assume very much
 * about the nodes you find.  Use this function to avoid oopses caused
 * by wrongly treating some non-I2C device as an i2c_client.
 */
struct i2c_client *i2c_verify_client(struct device *dev)
{
1173
	return (dev->type == &i2c_client_type)
1174 1175 1176 1177 1178 1179
			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
/* Return a unique address which takes the flags of the client into account */
static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
{
	unsigned short addr = client->addr;

	/* For some client flags, add an arbitrary offset to avoid collisions */
	if (client->flags & I2C_CLIENT_TEN)
		addr |= I2C_ADDR_OFFSET_TEN_BIT;

	if (client->flags & I2C_CLIENT_SLAVE)
		addr |= I2C_ADDR_OFFSET_SLAVE;

	return addr;
}

1195
/* This is a permissive address validity check, I2C address map constraints
L
Lucas De Marchi 已提交
1196
 * are purposely not enforced, except for the general call address. */
1197
static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
1198
{
1199
	if (flags & I2C_CLIENT_TEN) {
1200
		/* 10-bit address, all values are valid */
1201
		if (addr > 0x3ff)
1202 1203 1204
			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
1205
		if (addr == 0x00 || addr > 0x7f)
1206 1207 1208 1209 1210
			return -EINVAL;
	}
	return 0;
}

1211 1212 1213 1214
/* And this is a strict address validity check, used when probing. If a
 * device uses a reserved address, then it shouldn't be probed. 7-bit
 * addressing is assumed, 10-bit address devices are rare and should be
 * explicitly enumerated. */
1215
int i2c_check_7bit_addr_validity_strict(unsigned short addr)
1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231
{
	/*
	 * Reserved addresses per I2C specification:
	 *  0x00       General call address / START byte
	 *  0x01       CBUS address
	 *  0x02       Reserved for different bus format
	 *  0x03       Reserved for future purposes
	 *  0x04-0x07  Hs-mode master code
	 *  0x78-0x7b  10-bit slave addressing
	 *  0x7c-0x7f  Reserved for future purposes
	 */
	if (addr < 0x08 || addr > 0x77)
		return -EINVAL;
	return 0;
}

1232 1233 1234 1235 1236
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

1237
	if (client && i2c_encode_flags_to_addr(client) == addr)
1238 1239 1240 1241
		return -EBUSY;
	return 0;
}

1242 1243 1244
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
1245
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
1246 1247 1248 1249 1250
	int result;

	result = device_for_each_child(&adapter->dev, &addr,
					__i2c_check_addr_busy);

1251 1252
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270

	return result;
}

/* recurse down mux tree */
static int i2c_check_mux_children(struct device *dev, void *addrp)
{
	int result;

	if (dev->type == &i2c_adapter_type)
		result = device_for_each_child(dev, addrp,
						i2c_check_mux_children);
	else
		result = __i2c_check_addr_busy(dev, addrp);

	return result;
}

1271 1272
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
1273
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
1274 1275
	int result = 0;

1276 1277
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
1278 1279 1280 1281 1282 1283

	if (!result)
		result = device_for_each_child(&adapter->dev, &addr,
						i2c_check_mux_children);

	return result;
1284 1285
}

1286
/**
1287
 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
1288
 * @adapter: Target I2C bus segment
1289 1290
 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 *	locks only this branch in the adapter tree
1291
 */
1292 1293
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
				 unsigned int flags)
1294
{
1295
	rt_mutex_lock(&adapter->bus_lock);
1296 1297 1298
}

/**
1299
 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
1300
 * @adapter: Target I2C bus segment
1301 1302
 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	trylocks only this branch in the adapter tree
1303
 */
1304 1305
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
1306
{
1307
	return rt_mutex_trylock(&adapter->bus_lock);
1308 1309 1310
}

/**
1311
 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
1312
 * @adapter: Target I2C bus segment
1313 1314
 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	unlocks only this branch in the adapter tree
1315
 */
1316 1317
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
1318
{
1319
	rt_mutex_unlock(&adapter->bus_lock);
1320 1321
}

1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332
static void i2c_dev_set_name(struct i2c_adapter *adap,
			     struct i2c_client *client)
{
	struct acpi_device *adev = ACPI_COMPANION(&client->dev);

	if (adev) {
		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
		return;
	}

	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
1333
		     i2c_encode_flags_to_addr(client));
1334 1335
}

1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361
static int i2c_dev_irq_from_resources(const struct resource *resources,
				      unsigned int num_resources)
{
	struct irq_data *irqd;
	int i;

	for (i = 0; i < num_resources; i++) {
		const struct resource *r = &resources[i];

		if (resource_type(r) != IORESOURCE_IRQ)
			continue;

		if (r->flags & IORESOURCE_BITS) {
			irqd = irq_get_irq_data(r->start);
			if (!irqd)
				break;

			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
		}

		return r->start;
	}

	return 0;
}

1362
/**
1363
 * i2c_new_device - instantiate an i2c device
1364 1365
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
1366
 * Context: can sleep
1367
 *
1368 1369 1370 1371 1372 1373
 * Create an i2c device. Binding is handled through driver model
 * probe()/remove() methods.  A driver may be bound to this device when we
 * return from this function, or any later moment (e.g. maybe hotplugging will
 * load the driver module).  This call is not appropriate for use by mainboard
 * initialization logic, which usually runs during an arch_initcall() long
 * before any i2c_adapter could exist.
1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
 *
 * This returns the new i2c client, which may be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
	struct i2c_client	*client;
	int			status;

	client = kzalloc(sizeof *client, GFP_KERNEL);
	if (!client)
		return NULL;

	client->adapter = adap;

	client->dev.platform_data = info->platform_data;
1391

A
Anton Vorontsov 已提交
1392 1393 1394
	if (info->archdata)
		client->dev.archdata = *info->archdata;

M
Marc Pignat 已提交
1395
	client->flags = info->flags;
1396
	client->addr = info->addr;
1397

1398
	client->irq = info->irq;
1399 1400 1401
	if (!client->irq)
		client->irq = i2c_dev_irq_from_resources(info->resources,
							 info->num_resources);
1402 1403 1404

	strlcpy(client->name, info->type, sizeof(client->name));

1405
	status = i2c_check_addr_validity(client->addr, client->flags);
1406 1407 1408 1409 1410 1411
	if (status) {
		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
		goto out_err_silent;
	}

1412
	/* Check for address business */
1413
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1414 1415 1416 1417 1418
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
1419
	client->dev.type = &i2c_client_type;
1420
	client->dev.of_node = info->of_node;
1421
	client->dev.fwnode = info->fwnode;
1422

1423
	i2c_dev_set_name(adap, client);
1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434

	if (info->properties) {
		status = device_add_properties(&client->dev, info->properties);
		if (status) {
			dev_err(&adap->dev,
				"Failed to add properties to client %s: %d\n",
				client->name, status);
			goto out_err;
		}
	}

1435 1436
	status = device_register(&client->dev);
	if (status)
1437
		goto out_free_props;
1438 1439 1440 1441

	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
		client->name, dev_name(&client->dev));

1442
	return client;
1443

1444 1445 1446
out_free_props:
	if (info->properties)
		device_remove_properties(&client->dev);
1447
out_err:
1448 1449 1450
	dev_err(&adap->dev,
		"Failed to register i2c client %s at 0x%02x (%d)\n",
		client->name, client->addr, status);
1451
out_err_silent:
1452 1453
	kfree(client);
	return NULL;
1454 1455 1456 1457 1458 1459 1460
}
EXPORT_SYMBOL_GPL(i2c_new_device);


/**
 * i2c_unregister_device - reverse effect of i2c_new_device()
 * @client: value returned from i2c_new_device()
D
David Brownell 已提交
1461
 * Context: can sleep
1462 1463
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
1464
{
1465 1466
	if (client->dev.of_node)
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1467 1468
	if (ACPI_COMPANION(&client->dev))
		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
D
David Brownell 已提交
1469 1470
	device_unregister(&client->dev);
}
1471
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
1472 1473


J
Jean Delvare 已提交
1474 1475 1476 1477 1478
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

1479 1480 1481 1482 1483 1484 1485
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
1486 1487 1488 1489 1490 1491
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
1492 1493
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
1494
	.id_table	= dummy_id,
1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514
};

/**
 * i2c_new_dummy - return a new i2c device bound to a dummy driver
 * @adapter: the adapter managing the device
 * @address: seven bit address to be used
 * Context: can sleep
 *
 * This returns an I2C client bound to the "dummy" driver, intended for use
 * with devices that consume multiple addresses.  Examples of such chips
 * include various EEPROMS (like 24c04 and 24c08 models).
 *
 * These dummy devices have two main uses.  First, most I2C and SMBus calls
 * except i2c_transfer() need a client handle; the dummy will be that handle.
 * And second, this prevents the specified address from being bound to a
 * different driver.
 *
 * This returns the new i2c client, which should be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
Z
Zhenwen Xu 已提交
1515
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1516 1517
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
1518
		I2C_BOARD_INFO("dummy", address),
1519 1520 1521 1522 1523 1524
	};

	return i2c_new_device(adapter, &info);
}
EXPORT_SYMBOL_GPL(i2c_new_dummy);

1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565
/**
 * i2c_new_secondary_device - Helper to get the instantiated secondary address
 * and create the associated device
 * @client: Handle to the primary client
 * @name: Handle to specify which secondary address to get
 * @default_addr: Used as a fallback if no secondary address was specified
 * Context: can sleep
 *
 * I2C clients can be composed of multiple I2C slaves bound together in a single
 * component. The I2C client driver then binds to the master I2C slave and needs
 * to create I2C dummy clients to communicate with all the other slaves.
 *
 * This function creates and returns an I2C dummy client whose I2C address is
 * retrieved from the platform firmware based on the given slave name. If no
 * address is specified by the firmware default_addr is used.
 *
 * On DT-based platforms the address is retrieved from the "reg" property entry
 * cell whose "reg-names" value matches the slave name.
 *
 * This returns the new i2c client, which should be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
						const char *name,
						u16 default_addr)
{
	struct device_node *np = client->dev.of_node;
	u32 addr = default_addr;
	int i;

	if (np) {
		i = of_property_match_string(np, "reg-names", name);
		if (i >= 0)
			of_property_read_u32_index(np, "reg", i, &addr);
	}

	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
	return i2c_new_dummy(client->adapter, addr);
}
EXPORT_SYMBOL_GPL(i2c_new_secondary_device);

1566 1567
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
1568 1569
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
1570
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
1571
{
1572
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
1573 1574 1575
	complete(&adap->dev_released);
}

1576
unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1577 1578 1579 1580 1581 1582
{
	unsigned int depth = 0;

	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
		depth++;

1583 1584 1585
	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
		  "adapter depth exceeds lockdep subclass limit\n");

1586 1587
	return depth;
}
1588
EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1589

1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633
/*
 * Let users instantiate I2C devices through sysfs. This can be used when
 * platform initialization code doesn't contain the proper data for
 * whatever reason. Also useful for drivers that do device detection and
 * detection fails, either because the device uses an unexpected address,
 * or this is a compatible device with different ID register values.
 *
 * Parameter checking may look overzealous, but we really don't want
 * the user to provide incorrect parameters.
 */
static ssize_t
i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
		     const char *buf, size_t count)
{
	struct i2c_adapter *adap = to_i2c_adapter(dev);
	struct i2c_board_info info;
	struct i2c_client *client;
	char *blank, end;
	int res;

	memset(&info, 0, sizeof(struct i2c_board_info));

	blank = strchr(buf, ' ');
	if (!blank) {
		dev_err(dev, "%s: Missing parameters\n", "new_device");
		return -EINVAL;
	}
	if (blank - buf > I2C_NAME_SIZE - 1) {
		dev_err(dev, "%s: Invalid device name\n", "new_device");
		return -EINVAL;
	}
	memcpy(info.type, buf, blank - buf);

	/* Parse remaining parameters, reject extra parameters */
	res = sscanf(++blank, "%hi%c", &info.addr, &end);
	if (res < 1) {
		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
		return -EINVAL;
	}
	if (res > 1  && end != '\n') {
		dev_err(dev, "%s: Extra parameters\n", "new_device");
		return -EINVAL;
	}

1634 1635 1636 1637 1638 1639 1640 1641 1642 1643
	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
		info.flags |= I2C_CLIENT_TEN;
	}

	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
		info.flags |= I2C_CLIENT_SLAVE;
	}

1644 1645
	client = i2c_new_device(adap, &info);
	if (!client)
1646
		return -EINVAL;
1647 1648

	/* Keep track of the added device */
1649
	mutex_lock(&adap->userspace_clients_lock);
1650
	list_add_tail(&client->detected, &adap->userspace_clients);
1651
	mutex_unlock(&adap->userspace_clients_lock);
1652 1653 1654 1655 1656
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1657
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690

/*
 * And of course let the users delete the devices they instantiated, if
 * they got it wrong. This interface can only be used to delete devices
 * instantiated by i2c_sysfs_new_device above. This guarantees that we
 * don't delete devices to which some kernel code still has references.
 *
 * Parameter checking may look overzealous, but we really don't want
 * the user to delete the wrong device.
 */
static ssize_t
i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
			const char *buf, size_t count)
{
	struct i2c_adapter *adap = to_i2c_adapter(dev);
	struct i2c_client *client, *next;
	unsigned short addr;
	char end;
	int res;

	/* Parse parameters, reject extra parameters */
	res = sscanf(buf, "%hi%c", &addr, &end);
	if (res < 1) {
		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
		return -EINVAL;
	}
	if (res > 1  && end != '\n') {
		dev_err(dev, "%s: Extra parameters\n", "delete_device");
		return -EINVAL;
	}

	/* Make sure the device was added through sysfs */
	res = -ENOENT;
1691 1692
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1693 1694
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1695
		if (i2c_encode_flags_to_addr(client) == addr) {
1696 1697 1698 1699 1700 1701 1702 1703 1704
			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
				 "delete_device", client->name, client->addr);

			list_del(&client->detected);
			i2c_unregister_device(client);
			res = count;
			break;
		}
	}
1705
	mutex_unlock(&adap->userspace_clients_lock);
1706 1707 1708 1709 1710 1711

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1712 1713
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1714 1715 1716 1717 1718 1719 1720

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1721
ATTRIBUTE_GROUPS(i2c_adapter);
1722

1723
struct device_type i2c_adapter_type = {
1724
	.groups		= i2c_adapter_groups,
1725
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1726
};
1727
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1728

1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745
/**
 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
 * @dev: device, probably from some driver model iterator
 *
 * When traversing the driver model tree, perhaps using driver model
 * iterators like @device_for_each_child(), you can't assume very much
 * about the nodes you find.  Use this function to avoid oopses caused
 * by wrongly treating some non-I2C device as an i2c_adapter.
 */
struct i2c_adapter *i2c_verify_adapter(struct device *dev)
{
	return (dev->type == &i2c_adapter_type)
			? to_i2c_adapter(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_adapter);

1746 1747 1748 1749
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1750 1751 1752 1753
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1754
	down_read(&__i2c_board_lock);
1755 1756 1757 1758
	list_for_each_entry(devinfo, &__i2c_board_list, list) {
		if (devinfo->busnum == adapter->nr
				&& !i2c_new_device(adapter,
						&devinfo->board_info))
Z
Zhenwen Xu 已提交
1759 1760
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1761 1762
				devinfo->board_info.addr);
	}
1763
	up_read(&__i2c_board_lock);
1764 1765
}

1766 1767 1768
/* OF support code */

#if IS_ENABLED(CONFIG_OF)
1769 1770
static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
						 struct device_node *node)
1771
{
1772 1773 1774
	struct i2c_client *result;
	struct i2c_board_info info = {};
	struct dev_archdata dev_ad = {};
W
Wolfram Sang 已提交
1775 1776
	const __be32 *addr_be;
	u32 addr;
1777
	int len;
1778

1779
	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1780

1781 1782 1783 1784 1785
	if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
		dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1786

W
Wolfram Sang 已提交
1787 1788
	addr_be = of_get_property(node, "reg", &len);
	if (!addr_be || (len < sizeof(*addr_be))) {
1789 1790 1791 1792
		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1793

W
Wolfram Sang 已提交
1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805
	addr = be32_to_cpup(addr_be);
	if (addr & I2C_TEN_BIT_ADDRESS) {
		addr &= ~I2C_TEN_BIT_ADDRESS;
		info.flags |= I2C_CLIENT_TEN;
	}

	if (addr & I2C_OWN_SLAVE_ADDRESS) {
		addr &= ~I2C_OWN_SLAVE_ADDRESS;
		info.flags |= I2C_CLIENT_SLAVE;
	}

	if (i2c_check_addr_validity(addr, info.flags)) {
1806
		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1807
			addr, node->full_name);
1808 1809
		return ERR_PTR(-EINVAL);
	}
1810

W
Wolfram Sang 已提交
1811
	info.addr = addr;
1812 1813
	info.of_node = of_node_get(node);
	info.archdata = &dev_ad;
1814

1815 1816 1817
	if (of_property_read_bool(node, "host-notify"))
		info.flags |= I2C_CLIENT_HOST_NOTIFY;

1818 1819
	if (of_get_property(node, "wakeup-source", NULL))
		info.flags |= I2C_CLIENT_WAKE;
1820

1821 1822 1823 1824 1825 1826 1827 1828 1829
	result = i2c_new_device(adap, &info);
	if (result == NULL) {
		dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
			node->full_name);
		of_node_put(node);
		return ERR_PTR(-EINVAL);
	}
	return result;
}
1830

1831 1832
static void of_i2c_register_devices(struct i2c_adapter *adap)
{
1833
	struct device_node *bus, *node;
1834
	struct i2c_client *client;
1835

1836 1837 1838
	/* Only register child devices if the adapter has a node pointer set */
	if (!adap->dev.of_node)
		return;
1839

1840 1841
	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");

1842 1843 1844 1845 1846
	bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
	if (!bus)
		bus = of_node_get(adap->dev.of_node);

	for_each_available_child_of_node(bus, node) {
1847 1848
		if (of_node_test_and_set_flag(node, OF_POPULATED))
			continue;
1849 1850 1851 1852 1853 1854 1855 1856

		client = of_i2c_register_device(adap, node);
		if (IS_ERR(client)) {
			dev_warn(&adap->dev,
				 "Failed to create I2C device for %s\n",
				 node->full_name);
			of_node_clear_flag(node, OF_POPULATED);
		}
1857
	}
1858 1859

	of_node_put(bus);
1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870
}

static int of_dev_node_match(struct device *dev, void *data)
{
	return dev->of_node == data;
}

/* must call put_device() when done with returned i2c_client device */
struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
{
	struct device *dev;
1871
	struct i2c_client *client;
1872

1873
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1874 1875 1876
	if (!dev)
		return NULL;

1877 1878 1879 1880 1881
	client = i2c_verify_client(dev);
	if (!client)
		put_device(dev);

	return client;
1882 1883 1884 1885 1886 1887 1888
}
EXPORT_SYMBOL(of_find_i2c_device_by_node);

/* must call put_device() when done with returned i2c_adapter device */
struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
{
	struct device *dev;
1889
	struct i2c_adapter *adapter;
1890

1891
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1892 1893 1894
	if (!dev)
		return NULL;

1895 1896 1897 1898 1899
	adapter = i2c_verify_adapter(dev);
	if (!adapter)
		put_device(dev);

	return adapter;
1900 1901
}
EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919

/* must call i2c_put_adapter() when done with returned i2c_adapter device */
struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
{
	struct i2c_adapter *adapter;

	adapter = of_find_i2c_adapter_by_node(node);
	if (!adapter)
		return NULL;

	if (!try_module_get(adapter->owner)) {
		put_device(&adapter->dev);
		adapter = NULL;
	}

	return adapter;
}
EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949

static const struct of_device_id*
i2c_of_match_device_sysfs(const struct of_device_id *matches,
				  struct i2c_client *client)
{
	const char *name;

	for (; matches->compatible[0]; matches++) {
		/*
		 * Adding devices through the i2c sysfs interface provides us
		 * a string to match which may be compatible with the device
		 * tree compatible strings, however with no actual of_node the
		 * of_match_device() will not match
		 */
		if (sysfs_streq(client->name, matches->compatible))
			return matches;

		name = strchr(matches->compatible, ',');
		if (!name)
			name = matches->compatible;
		else
			name++;

		if (sysfs_streq(client->name, name))
			return matches;
	}

	return NULL;
}

1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965
const struct of_device_id
*i2c_of_match_device(const struct of_device_id *matches,
		     struct i2c_client *client)
{
	const struct of_device_id *match;

	if (!(client && matches))
		return NULL;

	match = of_match_device(matches, &client->dev);
	if (match)
		return match;

	return i2c_of_match_device_sysfs(matches, client);
}
EXPORT_SYMBOL_GPL(i2c_of_match_device);
1966 1967 1968 1969
#else
static void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif /* CONFIG_OF */

J
Jean Delvare 已提交
1970 1971
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1972
{
1973 1974 1975 1976
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

	/* Let legacy drivers scan this bus for matching devices */
1977
	if (driver->attach_adapter) {
J
Jean Delvare 已提交
1978 1979
		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
			 driver->driver.name);
1980 1981
		dev_warn(&adap->dev,
			 "Please use another way to instantiate your i2c_client\n");
1982 1983 1984 1985 1986 1987
		/* We ignore the return code; if it fails, too bad */
		driver->attach_adapter(adap);
	}
	return 0;
}

J
Jean Delvare 已提交
1988 1989 1990 1991 1992
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1993 1994 1995 1996 1997 1998
static const struct i2c_lock_operations i2c_adapter_lock_ops = {
	.lock_bus =    i2c_adapter_lock_bus,
	.trylock_bus = i2c_adapter_trylock_bus,
	.unlock_bus =  i2c_adapter_unlock_bus,
};

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071
static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
{
	struct irq_domain *domain = adap->host_notify_domain;
	irq_hw_number_t hwirq;

	if (!domain)
		return;

	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
		irq_dispose_mapping(irq_find_mapping(domain, hwirq));

	irq_domain_remove(domain);
	adap->host_notify_domain = NULL;
}

static int i2c_host_notify_irq_map(struct irq_domain *h,
					  unsigned int virq,
					  irq_hw_number_t hw_irq_num)
{
	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);

	return 0;
}

static const struct irq_domain_ops i2c_host_notify_irq_ops = {
	.map = i2c_host_notify_irq_map,
};

static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
{
	struct irq_domain *domain;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
		return 0;

	domain = irq_domain_create_linear(adap->dev.fwnode,
					  I2C_ADDR_7BITS_COUNT,
					  &i2c_host_notify_irq_ops, adap);
	if (!domain)
		return -ENOMEM;

	adap->host_notify_domain = domain;

	return 0;
}

/**
 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
 * I2C client.
 * @adap: the adapter
 * @addr: the I2C address of the notifying device
 * Context: can't sleep
 *
 * Helper function to be called from an I2C bus driver's interrupt
 * handler. It will schedule the Host Notify IRQ.
 */
int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
{
	int irq;

	if (!adap)
		return -EINVAL;

	irq = irq_find_mapping(adap->host_notify_domain, addr);
	if (irq <= 0)
		return -ENXIO;

	generic_handle_irq(irq);

	return 0;
}
EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);

2072
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
2073
{
2074
	int res = -EINVAL;
L
Linus Torvalds 已提交
2075

2076
	/* Can't register until after driver model init */
2077
	if (WARN_ON(!is_registered)) {
2078 2079 2080
		res = -EAGAIN;
		goto out_list;
	}
2081

2082
	/* Sanity checks */
2083
	if (WARN(!adap->name[0], "i2c adapter has no name"))
2084
		goto out_list;
2085 2086

	if (!adap->algo) {
W
Wolfram Sang 已提交
2087
		pr_err("adapter '%s': no algo supplied!\n", adap->name);
2088
		goto out_list;
2089 2090
	}

2091 2092
	if (!adap->lock_ops)
		adap->lock_ops = &i2c_adapter_lock_ops;
2093

2094
	rt_mutex_init(&adap->bus_lock);
2095
	rt_mutex_init(&adap->mux_lock);
2096
	mutex_init(&adap->userspace_clients_lock);
2097
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
2098

2099 2100 2101 2102
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

2103 2104 2105 2106 2107 2108 2109 2110
	/* register soft irqs for Host Notify */
	res = i2c_setup_host_notify_irq_domain(adap);
	if (res) {
		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
		       adap->name, res);
		goto out_list;
	}

2111
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
2112 2113
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
2114
	res = device_register(&adap->dev);
2115
	if (res) {
W
Wolfram Sang 已提交
2116
		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
2117
		goto out_list;
2118
	}
L
Linus Torvalds 已提交
2119

2120 2121
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

2122
	pm_runtime_no_callbacks(&adap->dev);
2123
	pm_suspend_ignore_children(&adap->dev, true);
2124
	pm_runtime_enable(&adap->dev);
2125

2126 2127 2128 2129 2130 2131 2132 2133
#ifdef CONFIG_I2C_COMPAT
	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
				       adap->dev.parent);
	if (res)
		dev_warn(&adap->dev,
			 "Failed to create compatibility class link\n");
#endif

2134
	i2c_init_recovery(adap);
2135

2136
	/* create pre-declared device nodes */
2137
	of_i2c_register_devices(adap);
2138 2139
	i2c_acpi_register_devices(adap);
	i2c_acpi_install_space_handler(adap);
2140

2141 2142 2143
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

2144
	/* Notify drivers */
2145
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
2146
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
2147
	mutex_unlock(&core_lock);
2148 2149

	return 0;
2150 2151

out_list:
2152
	mutex_lock(&core_lock);
2153
	idr_remove(&i2c_adapter_idr, adap->nr);
2154 2155
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
2156 2157
}

2158 2159 2160 2161 2162 2163 2164 2165 2166
/**
 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
 * @adap: the adapter to register (with adap->nr initialized)
 * Context: can sleep
 *
 * See i2c_add_numbered_adapter() for details.
 */
static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
2167
	int id;
2168 2169

	mutex_lock(&core_lock);
2170
	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
2171
	mutex_unlock(&core_lock);
2172
	if (WARN(id < 0, "couldn't get idr"))
2173 2174 2175 2176 2177
		return id == -ENOSPC ? -EBUSY : id;

	return i2c_register_adapter(adap);
}

2178 2179 2180
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
2181
 * Context: can sleep
2182 2183
 *
 * This routine is used to declare an I2C adapter when its bus number
2184 2185 2186
 * doesn't matter or when its bus number is specified by an dt alias.
 * Examples of bases when the bus number doesn't matter: I2C adapters
 * dynamically added by USB links or PCI plugin cards.
2187 2188 2189 2190 2191 2192 2193
 *
 * When this returns zero, a new bus number was allocated and stored
 * in adap->nr, and the specified adapter became available for clients.
 * Otherwise, a negative errno value is returned.
 */
int i2c_add_adapter(struct i2c_adapter *adapter)
{
2194
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
2195
	int id;
2196

2197 2198 2199 2200 2201 2202 2203 2204
	if (dev->of_node) {
		id = of_alias_get_id(dev->of_node, "i2c");
		if (id >= 0) {
			adapter->nr = id;
			return __i2c_add_numbered_adapter(adapter);
		}
	}

J
Jean Delvare 已提交
2205
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
2206 2207
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
2208
	mutex_unlock(&core_lock);
2209
	if (WARN(id < 0, "couldn't get idr"))
T
Tejun Heo 已提交
2210
		return id;
2211 2212

	adapter->nr = id;
T
Tejun Heo 已提交
2213

2214 2215 2216 2217 2218 2219 2220
	return i2c_register_adapter(adapter);
}
EXPORT_SYMBOL(i2c_add_adapter);

/**
 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
 * @adap: the adapter to register (with adap->nr initialized)
D
David Brownell 已提交
2221
 * Context: can sleep
2222 2223
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
2224 2225
 * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
 * or otherwise built in to the system's mainboard, and where i2c_board_info
2226 2227
 * is used to properly configure I2C devices.
 *
2228 2229 2230
 * If the requested bus number is set to -1, then this function will behave
 * identically to i2c_add_adapter, and will dynamically assign a bus number.
 *
2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242
 * If no devices have pre-been declared for this bus, then be sure to
 * register the adapter before any dynamically allocated ones.  Otherwise
 * the required bus ID may not be available.
 *
 * When this returns zero, the specified adapter became available for
 * clients using the bus number provided in adap->nr.  Also, the table
 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
 * and the appropriate driver model device nodes are created.  Otherwise, a
 * negative errno value is returned.
 */
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
2243 2244
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
2245

2246
	return __i2c_add_numbered_adapter(adap);
2247 2248 2249
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
2250
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
2251
			      struct i2c_adapter *adapter)
2252
{
2253
	struct i2c_client *client, *_n;
2254

2255 2256
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
2257 2258 2259 2260 2261 2262 2263 2264
	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
		if (client->adapter == adapter) {
			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
				client->name, client->addr);
			list_del(&client->detected);
			i2c_unregister_device(client);
		}
	}
2265 2266
}

2267
static int __unregister_client(struct device *dev, void *dummy)
2268 2269 2270 2271 2272 2273 2274 2275
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client && strcmp(client->name, "dummy"))
		i2c_unregister_device(client);
	return 0;
}

static int __unregister_dummy(struct device *dev, void *dummy)
2276 2277 2278 2279 2280 2281 2282
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client)
		i2c_unregister_device(client);
	return 0;
}

J
Jean Delvare 已提交
2283 2284
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
2285 2286
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
2287 2288
}

D
David Brownell 已提交
2289 2290 2291 2292 2293 2294 2295 2296
/**
 * i2c_del_adapter - unregister I2C adapter
 * @adap: the adapter being unregistered
 * Context: can sleep
 *
 * This unregisters an I2C adapter which was previously registered
 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
 */
2297
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
2298
{
2299
	struct i2c_adapter *found;
2300
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
2301 2302

	/* First make sure that this adapter was ever added */
2303 2304 2305 2306
	mutex_lock(&core_lock);
	found = idr_find(&i2c_adapter_idr, adap->nr);
	mutex_unlock(&core_lock);
	if (found != adap) {
W
Wolfram Sang 已提交
2307
		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
2308
		return;
L
Linus Torvalds 已提交
2309 2310
	}

2311
	i2c_acpi_remove_space_handler(adap);
2312
	/* Tell drivers about this removal */
2313
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
2314
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
2315
			       __process_removed_adapter);
2316
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
2317

2318
	/* Remove devices instantiated from sysfs */
2319 2320
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
2321 2322 2323 2324 2325 2326
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
			client->addr);
		list_del(&client->detected);
		i2c_unregister_device(client);
2327
	}
2328
	mutex_unlock(&adap->userspace_clients_lock);
2329

2330
	/* Detach any active clients. This can't fail, thus we do not
2331 2332 2333 2334
	 * check the returned value. This is a two-pass process, because
	 * we can't remove the dummy devices during the first pass: they
	 * could have been instantiated by real devices wishing to clean
	 * them up properly, so we give them a chance to do that first. */
L
Lars-Peter Clausen 已提交
2335 2336
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
2337

2338 2339 2340 2341 2342
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

2343 2344 2345
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

2346 2347
	pm_runtime_disable(&adap->dev);

2348 2349
	i2c_host_notify_irq_teardown(adap);

2350 2351 2352 2353 2354
	/* wait until all references to the device are gone
	 *
	 * FIXME: This is old code and should ideally be replaced by an
	 * alternative which results in decoupling the lifetime of the struct
	 * device from the i2c_adapter, like spi or netdev do. Any solution
2355
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
2356
	 */
L
Linus Torvalds 已提交
2357 2358 2359 2360
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

2361
	/* free bus id */
2362
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
2363
	idr_remove(&i2c_adapter_idr, adap->nr);
2364
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
2365

2366 2367 2368
	/* Clear the device structure in case this adapter is ever going to be
	   added again */
	memset(&adap->dev, 0, sizeof(adap->dev));
L
Linus Torvalds 已提交
2369
}
D
David Brownell 已提交
2370
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
2371

2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423
/**
 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
 * @dev: The device to scan for I2C timing properties
 * @t: the i2c_timings struct to be filled with values
 * @use_defaults: bool to use sane defaults derived from the I2C specification
 *		  when properties are not found, otherwise use 0
 *
 * Scan the device for the generic I2C properties describing timing parameters
 * for the signal and fill the given struct with the results. If a property was
 * not found and use_defaults was true, then maximum timings are assumed which
 * are derived from the I2C specification. If use_defaults is not used, the
 * results will be 0, so drivers can apply their own defaults later. The latter
 * is mainly intended for avoiding regressions of existing drivers which want
 * to switch to this function. New drivers almost always should use the defaults.
 */

void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
{
	int ret;

	memset(t, 0, sizeof(*t));

	ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
	if (ret && use_defaults)
		t->bus_freq_hz = 100000;

	ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
	if (ret && use_defaults) {
		if (t->bus_freq_hz <= 100000)
			t->scl_rise_ns = 1000;
		else if (t->bus_freq_hz <= 400000)
			t->scl_rise_ns = 300;
		else
			t->scl_rise_ns = 120;
	}

	ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
	if (ret && use_defaults) {
		if (t->bus_freq_hz <= 400000)
			t->scl_fall_ns = 300;
		else
			t->scl_fall_ns = 120;
	}

	device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);

	ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
	if (ret && use_defaults)
		t->sda_fall_ns = t->scl_fall_ns;
}
EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);

D
David Brownell 已提交
2424 2425
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
{
	int res;

	mutex_lock(&core_lock);
	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
	mutex_unlock(&core_lock);

	return res;
}
EXPORT_SYMBOL_GPL(i2c_for_each_dev);

J
Jean Delvare 已提交
2438
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
2439
{
2440 2441
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
2442
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
2443 2444
}

D
David Brownell 已提交
2445 2446
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
2447
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
2448 2449
 */

2450
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
2451
{
2452
	int res;
L
Linus Torvalds 已提交
2453

2454
	/* Can't register until after driver model init */
2455
	if (WARN_ON(!is_registered))
2456 2457
		return -EAGAIN;

L
Linus Torvalds 已提交
2458
	/* add the driver to the list of i2c drivers in the driver core */
2459
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
2460
	driver->driver.bus = &i2c_bus_type;
2461
	INIT_LIST_HEAD(&driver->clients);
L
Linus Torvalds 已提交
2462

2463
	/* When registration returns, the driver core
2464 2465
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
2466 2467
	res = driver_register(&driver->driver);
	if (res)
2468
		return res;
D
David Brownell 已提交
2469

W
Wolfram Sang 已提交
2470
	pr_debug("driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
2471

2472
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
2473
	i2c_for_each_dev(driver, __process_new_driver);
2474

D
Dave Young 已提交
2475 2476 2477 2478
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
2479
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
2480
{
L
Lars-Peter Clausen 已提交
2481 2482 2483
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
2484 2485
}

D
David Brownell 已提交
2486 2487 2488
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
2489
 * Context: can sleep
D
David Brownell 已提交
2490
 */
2491
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
2492
{
J
Jean Delvare 已提交
2493
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
2494 2495

	driver_unregister(&driver->driver);
W
Wolfram Sang 已提交
2496
	pr_debug("driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
2497
}
D
David Brownell 已提交
2498
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
2499

D
David Brownell 已提交
2500 2501
/* ------------------------------------------------------------------------- */

2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513
/**
 * i2c_use_client - increments the reference count of the i2c client structure
 * @client: the client being referenced
 *
 * Each live reference to a client should be refcounted. The driver model does
 * that automatically as part of driver binding, so that most drivers don't
 * need to do this explicitly: they hold a reference until they're unbound
 * from the device.
 *
 * A pointer to the client with the incremented reference counter is returned.
 */
struct i2c_client *i2c_use_client(struct i2c_client *client)
L
Linus Torvalds 已提交
2514
{
2515 2516 2517
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
2518
}
D
David Brownell 已提交
2519
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
2520

2521 2522 2523 2524 2525 2526 2527
/**
 * i2c_release_client - release a use of the i2c client structure
 * @client: the client being no longer referenced
 *
 * Must be called when a user of a client is finished with it.
 */
void i2c_release_client(struct i2c_client *client)
L
Linus Torvalds 已提交
2528
{
2529 2530
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
2531
}
D
David Brownell 已提交
2532
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
2533

2534 2535 2536 2537 2538 2539 2540 2541 2542
struct i2c_cmd_arg {
	unsigned	cmd;
	void		*arg;
};

static int i2c_cmd(struct device *dev, void *_arg)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_cmd_arg	*arg = _arg;
2543 2544 2545 2546
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
2547

2548 2549 2550
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
2551 2552 2553
	return 0;
}

L
Linus Torvalds 已提交
2554 2555
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
2556
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
2557

2558 2559 2560
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
2561
}
D
David Brownell 已提交
2562
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
2563

2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
			 void *arg)
{
	struct of_reconfig_data *rd = arg;
	struct i2c_adapter *adap;
	struct i2c_client *client;

	switch (of_reconfig_get_state_change(action, rd)) {
	case OF_RECONFIG_CHANGE_ADD:
		adap = of_find_i2c_adapter_by_node(rd->dn->parent);
		if (adap == NULL)
			return NOTIFY_OK;	/* not for us */

2578 2579 2580 2581 2582
		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
			put_device(&adap->dev);
			return NOTIFY_OK;
		}

2583 2584 2585 2586
		client = of_i2c_register_device(adap, rd->dn);
		put_device(&adap->dev);

		if (IS_ERR(client)) {
2587 2588
			dev_err(&adap->dev, "failed to create client for '%s'\n",
				 rd->dn->full_name);
2589
			of_node_clear_flag(rd->dn, OF_POPULATED);
2590 2591 2592 2593
			return notifier_from_errno(PTR_ERR(client));
		}
		break;
	case OF_RECONFIG_CHANGE_REMOVE:
2594 2595 2596 2597
		/* already depopulated? */
		if (!of_node_check_flag(rd->dn, OF_POPULATED))
			return NOTIFY_OK;

2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619
		/* find our device by node */
		client = of_find_i2c_device_by_node(rd->dn);
		if (client == NULL)
			return NOTIFY_OK;	/* no? not meant for us */

		/* unregister takes one ref away */
		i2c_unregister_device(client);

		/* and put the reference of the find */
		put_device(&client->dev);
		break;
	}

	return NOTIFY_OK;
}
static struct notifier_block i2c_of_notifier = {
	.notifier_call = of_i2c_notify,
};
#else
extern struct notifier_block i2c_of_notifier;
#endif /* CONFIG_OF_DYNAMIC */

L
Linus Torvalds 已提交
2620 2621 2622 2623
static int __init i2c_init(void)
{
	int retval;

2624 2625 2626 2627 2628 2629 2630
	retval = of_alias_get_highest_id("i2c");

	down_write(&__i2c_board_lock);
	if (retval >= __i2c_first_dynamic_bus_num)
		__i2c_first_dynamic_bus_num = retval + 1;
	up_write(&__i2c_board_lock);

L
Linus Torvalds 已提交
2631 2632 2633
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
2634 2635 2636

	is_registered = true;

2637 2638 2639 2640 2641 2642 2643
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
2644 2645
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
2646
		goto class_err;
2647 2648 2649

	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2650 2651
	if (IS_ENABLED(CONFIG_ACPI))
		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2652

2653 2654
	return 0;

2655 2656 2657
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
2658
bus_err:
2659
#endif
2660
	is_registered = false;
2661 2662
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
2663 2664 2665 2666
}

static void __exit i2c_exit(void)
{
2667 2668
	if (IS_ENABLED(CONFIG_ACPI))
		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2669 2670
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2671
	i2c_del_driver(&dummy_driver);
2672 2673 2674
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
2675
	bus_unregister(&i2c_bus_type);
2676
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
2677 2678
}

D
David Brownell 已提交
2679 2680 2681 2682
/* We must initialize early, because some subsystems register i2c drivers
 * in subsys_initcall() code, but are linked (and initialized) before i2c.
 */
postcore_initcall(i2c_init);
L
Linus Torvalds 已提交
2683 2684 2685 2686 2687 2688 2689
module_exit(i2c_exit);

/* ----------------------------------------------------
 * the functional interface to the i2c busses.
 * ----------------------------------------------------
 */

W
Wolfram Sang 已提交
2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748
/* Check if val is exceeding the quirk IFF quirk is non 0 */
#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))

static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
{
	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
			    err_msg, msg->addr, msg->len,
			    msg->flags & I2C_M_RD ? "read" : "write");
	return -EOPNOTSUPP;
}

static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	const struct i2c_adapter_quirks *q = adap->quirks;
	int max_num = q->max_num_msgs, i;
	bool do_len_check = true;

	if (q->flags & I2C_AQ_COMB) {
		max_num = 2;

		/* special checks for combined messages */
		if (num == 2) {
			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");

			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");

			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");

			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
				return i2c_quirk_error(adap, &msgs[0], "msg too long");

			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
				return i2c_quirk_error(adap, &msgs[1], "msg too long");

			do_len_check = false;
		}
	}

	if (i2c_quirk_exceeded(num, max_num))
		return i2c_quirk_error(adap, &msgs[0], "too many messages");

	for (i = 0; i < num; i++) {
		u16 len = msgs[i].len;

		if (msgs[i].flags & I2C_M_RD) {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
		} else {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
		}
	}

	return 0;
}

2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765
/**
 * __i2c_transfer - unlocked flavor of i2c_transfer
 * @adap: Handle to I2C bus
 * @msgs: One or more messages to execute before STOP is issued to
 *	terminate the operation; each message begins with a START.
 * @num: Number of messages to be executed.
 *
 * Returns negative errno, else the number of messages executed.
 *
 * Adapter lock must be held when calling this function. No debug logging
 * takes place. adap->algo->master_xfer existence isn't checked.
 */
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	unsigned long orig_jiffies;
	int ret, try;

W
Wolfram Sang 已提交
2766 2767 2768
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781
	/* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
	 * enabled.  This is an efficient way of keeping the for-loop from
	 * being executed when not needed.
	 */
	if (static_key_false(&i2c_trace_msg)) {
		int i;
		for (i = 0; i < num; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_read(adap, &msgs[i], i);
			else
				trace_i2c_write(adap, &msgs[i], i);
	}

2782 2783 2784 2785 2786 2787 2788 2789 2790 2791
	/* Retry automatically on arbitration loss */
	orig_jiffies = jiffies;
	for (ret = 0, try = 0; try <= adap->retries; try++) {
		ret = adap->algo->master_xfer(adap, msgs, num);
		if (ret != -EAGAIN)
			break;
		if (time_after(jiffies, orig_jiffies + adap->timeout))
			break;
	}

2792 2793 2794 2795 2796 2797 2798 2799
	if (static_key_false(&i2c_trace_msg)) {
		int i;
		for (i = 0; i < ret; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_reply(adap, &msgs[i], i);
		trace_i2c_result(adap, i, ret);
	}

2800 2801 2802 2803
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815
/**
 * i2c_transfer - execute a single or combined I2C message
 * @adap: Handle to I2C bus
 * @msgs: One or more messages to execute before STOP is issued to
 *	terminate the operation; each message begins with a START.
 * @num: Number of messages to be executed.
 *
 * Returns negative errno, else the number of messages executed.
 *
 * Note that there is no requirement that each message be sent to
 * the same slave address, although that is the most common model.
 */
Z
Zhenwen Xu 已提交
2816
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
2817
{
2818
	int ret;
L
Linus Torvalds 已提交
2819

2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836
	/* REVISIT the fault reporting model here is weak:
	 *
	 *  - When we get an error after receiving N bytes from a slave,
	 *    there is no way to report "N".
	 *
	 *  - When we get a NAK after transmitting N bytes to a slave,
	 *    there is no way to report "N" ... or to let the master
	 *    continue executing the rest of this combined message, if
	 *    that's the appropriate response.
	 *
	 *  - When for example "num" is two and we successfully complete
	 *    the first message but get an error part way through the
	 *    second, it's unclear whether that should be reported as
	 *    one (discarding status on the second message) or errno
	 *    (discarding status on the first one).
	 */

L
Linus Torvalds 已提交
2837 2838 2839
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
2840 2841 2842 2843
			dev_dbg(&adap->dev,
				"master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
				ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
				msgs[ret].addr, msgs[ret].len,
2844
				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
L
Linus Torvalds 已提交
2845 2846 2847
		}
#endif

2848
		if (in_atomic() || irqs_disabled()) {
2849
			ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
2850 2851 2852 2853
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
2854
			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
2855 2856
		}

2857
		ret = __i2c_transfer(adap, msgs, num);
2858
		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
2859 2860 2861 2862

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
2863
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
2864 2865
	}
}
D
David Brownell 已提交
2866
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
2867

2868 2869 2870 2871
/**
 * i2c_master_send - issue a single I2C message in master transmit mode
 * @client: Handle to slave device
 * @buf: Data that will be written to the slave
2872
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2873 2874 2875
 *
 * Returns negative errno, or else the number of bytes written.
 */
2876
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
L
Linus Torvalds 已提交
2877 2878
{
	int ret;
2879
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2880 2881
	struct i2c_msg msg;

2882 2883 2884 2885
	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = (char *)buf;
D
David Brownell 已提交
2886

2887
	ret = i2c_transfer(adap, &msg, 1);
L
Linus Torvalds 已提交
2888

2889 2890 2891 2892
	/*
	 * If everything went ok (i.e. 1 msg transmitted), return #bytes
	 * transmitted, else error code.
	 */
2893
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2894
}
D
David Brownell 已提交
2895
EXPORT_SYMBOL(i2c_master_send);
L
Linus Torvalds 已提交
2896

2897 2898 2899 2900
/**
 * i2c_master_recv - issue a single I2C message in master receive mode
 * @client: Handle to slave device
 * @buf: Where to store data read from slave
2901
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2902 2903 2904
 *
 * Returns negative errno, or else the number of bytes read.
 */
2905
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
L
Linus Torvalds 已提交
2906
{
2907
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2908 2909
	struct i2c_msg msg;
	int ret;
2910 2911 2912 2913 2914 2915 2916 2917 2918

	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.flags |= I2C_M_RD;
	msg.len = count;
	msg.buf = buf;

	ret = i2c_transfer(adap, &msg, 1);

2919 2920 2921 2922
	/*
	 * If everything went ok (i.e. 1 msg received), return #bytes received,
	 * else error code.
	 */
2923
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2924
}
D
David Brownell 已提交
2925
EXPORT_SYMBOL(i2c_master_recv);
L
Linus Torvalds 已提交
2926 2927 2928 2929 2930 2931 2932

/* ----------------------------------------------------
 * the i2c address scanning function
 * Will not work for 10-bit addresses!
 * ----------------------------------------------------
 */

2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956
/*
 * Legacy default probe function, mostly relevant for SMBus. The default
 * probe method is a quick write, but it is known to corrupt the 24RF08
 * EEPROMs due to a state machine bug, and could also irreversibly
 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
 * we use a short byte read instead. Also, some bus drivers don't implement
 * quick write, so we fallback to a byte read in that case too.
 * On x86, there is another special case for FSC hardware monitoring chips,
 * which want regular byte reads (address 0x73.) Fortunately, these are the
 * only known chips using this I2C address on PC hardware.
 * Returns 1 if probe succeeded, 0 if not.
 */
static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
{
	int err;
	union i2c_smbus_data dummy;

#ifdef CONFIG_X86
	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
				     I2C_SMBUS_BYTE_DATA, &dummy);
	else
#endif
2957 2958
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2959 2960
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2961 2962 2963 2964
	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
				     I2C_SMBUS_BYTE, &dummy);
	else {
2965 2966
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2967 2968
		err = -EOPNOTSUPP;
	}
2969 2970 2971 2972

	return err >= 0;
}

J
Jean Delvare 已提交
2973
static int i2c_detect_address(struct i2c_client *temp_client,
2974 2975 2976 2977 2978 2979 2980 2981
			      struct i2c_driver *driver)
{
	struct i2c_board_info info;
	struct i2c_adapter *adapter = temp_client->adapter;
	int addr = temp_client->addr;
	int err;

	/* Make sure the address is valid */
2982
	err = i2c_check_7bit_addr_validity_strict(addr);
2983
	if (err) {
2984 2985
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2986
		return err;
2987 2988
	}

2989
	/* Skip if already in use (7 bit, no need to encode flags) */
2990
	if (i2c_check_addr_busy(adapter, addr))
2991 2992
		return 0;

J
Jean Delvare 已提交
2993
	/* Make sure there is something at this address */
2994 2995
	if (!i2c_default_probe(adapter, addr))
		return 0;
2996 2997 2998 2999

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
3000
	err = driver->detect(temp_client, &info);
3001 3002 3003 3004 3005 3006 3007 3008
	if (err) {
		/* -ENODEV is returned if the detection fails. We catch it
		   here as this isn't an error. */
		return err == -ENODEV ? 0 : err;
	}

	/* Consistency check */
	if (info.type[0] == '\0') {
3009 3010 3011
		dev_err(&adapter->dev,
			"%s detection function provided no name for 0x%x\n",
			driver->driver.name, addr);
3012 3013 3014 3015
	} else {
		struct i2c_client *client;

		/* Detection succeeded, instantiate the device */
3016 3017 3018 3019 3020 3021 3022
		if (adapter->class & I2C_CLASS_DEPRECATED)
			dev_warn(&adapter->dev,
				"This adapter will soon drop class based instantiation of devices. "
				"Please make sure client 0x%02x gets instantiated by other means. "
				"Check 'Documentation/i2c/instantiating-devices' for details.\n",
				info.addr);

3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036
		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
			info.type, info.addr);
		client = i2c_new_device(adapter, &info);
		if (client)
			list_add_tail(&client->detected, &driver->clients);
		else
			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
				info.type, info.addr);
	}
	return 0;
}

static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
{
3037
	const unsigned short *address_list;
3038 3039 3040 3041
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

3042 3043
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
3044 3045
		return 0;

3046 3047 3048
	/* Warn that the adapter lost class based instantiation */
	if (adapter->class == I2C_CLASS_DEPRECATED) {
		dev_dbg(&adapter->dev,
3049 3050
			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
			"If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
3051 3052 3053 3054
			driver->driver.name);
		return 0;
	}

J
Jean Delvare 已提交
3055 3056 3057 3058
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

3059 3060 3061 3062 3063 3064
	/* Set up a temporary client to help detect callback */
	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
	if (!temp_client)
		return -ENOMEM;
	temp_client->adapter = adapter;

3065
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
3066 3067 3068
		dev_dbg(&adapter->dev,
			"found normal entry for adapter %d, addr 0x%02x\n",
			adap_id, address_list[i]);
3069
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
3070
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
3071 3072
		if (unlikely(err))
			break;
3073 3074 3075 3076 3077 3078
	}

	kfree(temp_client);
	return err;
}

3079 3080 3081 3082 3083 3084 3085
int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
{
	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
			      I2C_SMBUS_QUICK, NULL) >= 0;
}
EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);

J
Jean Delvare 已提交
3086 3087 3088
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
3089 3090
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
3091 3092 3093
{
	int i;

3094
	if (!probe)
3095
		probe = i2c_default_probe;
J
Jean Delvare 已提交
3096 3097 3098

	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
3099
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
3100 3101
			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
				 addr_list[i]);
J
Jean Delvare 已提交
3102 3103 3104
			continue;
		}

3105
		/* Check address availability (7 bit, no need to encode flags) */
3106
		if (i2c_check_addr_busy(adap, addr_list[i])) {
3107 3108 3109
			dev_dbg(&adap->dev,
				"Address 0x%02x already in use, not probing\n",
				addr_list[i]);
J
Jean Delvare 已提交
3110 3111 3112
			continue;
		}

3113
		/* Test address responsiveness */
3114
		if (probe(adap, addr_list[i]))
3115
			break;
J
Jean Delvare 已提交
3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127
	}

	if (addr_list[i] == I2C_CLIENT_END) {
		dev_dbg(&adap->dev, "Probing failed, no device found\n");
		return NULL;
	}

	info->addr = addr_list[i];
	return i2c_new_device(adap, info);
}
EXPORT_SYMBOL_GPL(i2c_new_probed_device);

3128
struct i2c_adapter *i2c_get_adapter(int nr)
L
Linus Torvalds 已提交
3129 3130
{
	struct i2c_adapter *adapter;
D
David Brownell 已提交
3131

J
Jean Delvare 已提交
3132
	mutex_lock(&core_lock);
3133
	adapter = idr_find(&i2c_adapter_idr, nr);
3134 3135 3136 3137 3138 3139
	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
3140 3141
		adapter = NULL;

3142
 exit:
J
Jean Delvare 已提交
3143
	mutex_unlock(&core_lock);
3144
	return adapter;
L
Linus Torvalds 已提交
3145
}
D
David Brownell 已提交
3146
EXPORT_SYMBOL(i2c_get_adapter);
L
Linus Torvalds 已提交
3147 3148 3149

void i2c_put_adapter(struct i2c_adapter *adap)
{
3150 3151 3152 3153 3154
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
L
Linus Torvalds 已提交
3155
}
D
David Brownell 已提交
3156
EXPORT_SYMBOL(i2c_put_adapter);
L
Linus Torvalds 已提交
3157 3158 3159

/* The SMBus parts */

D
David Brownell 已提交
3160
#define POLY    (0x1070U << 3)
Z
Zhenwen Xu 已提交
3161
static u8 crc8(u16 data)
L
Linus Torvalds 已提交
3162 3163
{
	int i;
D
David Brownell 已提交
3164

3165
	for (i = 0; i < 8; i++) {
D
David Brownell 已提交
3166
		if (data & 0x8000)
L
Linus Torvalds 已提交
3167 3168 3169 3170 3171 3172
			data = data ^ POLY;
		data = data << 1;
	}
	return (u8)(data >> 8);
}

3173 3174
/* Incremental CRC8 over count bytes in the array pointed to by p */
static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
L
Linus Torvalds 已提交
3175 3176 3177
{
	int i;

3178
	for (i = 0; i < count; i++)
3179
		crc = crc8((crc ^ p[i]) << 8);
L
Linus Torvalds 已提交
3180 3181 3182
	return crc;
}

3183 3184
/* Assume a 7-bit address, which is reasonable for SMBus */
static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
L
Linus Torvalds 已提交
3185
{
3186
	/* The address will be sent first */
3187
	u8 addr = i2c_8bit_addr_from_msg(msg);
3188 3189 3190 3191
	pec = i2c_smbus_pec(pec, &addr, 1);

	/* The data buffer follows */
	return i2c_smbus_pec(pec, msg->buf, msg->len);
L
Linus Torvalds 已提交
3192 3193
}

3194 3195
/* Used for write only transactions */
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
L
Linus Torvalds 已提交
3196
{
3197 3198
	msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
	msg->len++;
L
Linus Torvalds 已提交
3199 3200
}

3201 3202 3203 3204 3205 3206
/* Return <0 on CRC error
   If there was a write before this read (most cases) we need to take the
   partial CRC from the write part into account.
   Note that this function does modify the message (we need to decrease the
   message length to hide the CRC byte from the caller). */
static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
L
Linus Torvalds 已提交
3207
{
3208 3209
	u8 rpec = msg->buf[--msg->len];
	cpec = i2c_smbus_msg_pec(cpec, msg);
L
Linus Torvalds 已提交
3210 3211

	if (rpec != cpec) {
W
Wolfram Sang 已提交
3212
		pr_debug("Bad PEC 0x%02x vs. 0x%02x\n",
L
Linus Torvalds 已提交
3213
			rpec, cpec);
D
David Brownell 已提交
3214
		return -EBADMSG;
L
Linus Torvalds 已提交
3215
	}
D
David Brownell 已提交
3216
	return 0;
L
Linus Torvalds 已提交
3217 3218
}

3219 3220 3221 3222 3223 3224 3225
/**
 * i2c_smbus_read_byte - SMBus "receive byte" protocol
 * @client: Handle to slave device
 *
 * This executes the SMBus "receive byte" protocol, returning negative errno
 * else the byte received from the device.
 */
3226
s32 i2c_smbus_read_byte(const struct i2c_client *client)
L
Linus Torvalds 已提交
3227 3228
{
	union i2c_smbus_data data;
D
David Brownell 已提交
3229 3230 3231 3232 3233 3234
	int status;

	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, 0,
				I2C_SMBUS_BYTE, &data);
	return (status < 0) ? status : data.byte;
L
Linus Torvalds 已提交
3235
}
D
David Brownell 已提交
3236
EXPORT_SYMBOL(i2c_smbus_read_byte);
L
Linus Torvalds 已提交
3237

3238 3239 3240 3241 3242 3243 3244 3245
/**
 * i2c_smbus_write_byte - SMBus "send byte" protocol
 * @client: Handle to slave device
 * @value: Byte to be sent
 *
 * This executes the SMBus "send byte" protocol, returning negative errno
 * else zero on success.
 */
3246
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
L
Linus Torvalds 已提交
3247
{
3248
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3249
	                      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
L
Linus Torvalds 已提交
3250
}
D
David Brownell 已提交
3251
EXPORT_SYMBOL(i2c_smbus_write_byte);
L
Linus Torvalds 已提交
3252

3253 3254 3255 3256 3257 3258 3259 3260
/**
 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 *
 * This executes the SMBus "read byte" protocol, returning negative errno
 * else a data byte received from the device.
 */
3261
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
3262 3263
{
	union i2c_smbus_data data;
D
David Brownell 已提交
3264 3265 3266 3267 3268 3269
	int status;

	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BYTE_DATA, &data);
	return (status < 0) ? status : data.byte;
L
Linus Torvalds 已提交
3270
}
D
David Brownell 已提交
3271
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
L
Linus Torvalds 已提交
3272

3273 3274 3275 3276 3277 3278 3279 3280 3281
/**
 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @value: Byte being written
 *
 * This executes the SMBus "write byte" protocol, returning negative errno
 * else zero on success.
 */
3282 3283
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
			      u8 value)
L
Linus Torvalds 已提交
3284 3285 3286
{
	union i2c_smbus_data data;
	data.byte = value;
3287 3288 3289
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_BYTE_DATA, &data);
L
Linus Torvalds 已提交
3290
}
D
David Brownell 已提交
3291
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
L
Linus Torvalds 已提交
3292

3293 3294 3295 3296 3297 3298 3299 3300
/**
 * i2c_smbus_read_word_data - SMBus "read word" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 *
 * This executes the SMBus "read word" protocol, returning negative errno
 * else a 16-bit unsigned "word" received from the device.
 */
3301
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
3302 3303
{
	union i2c_smbus_data data;
D
David Brownell 已提交
3304 3305 3306 3307 3308 3309
	int status;

	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_WORD_DATA, &data);
	return (status < 0) ? status : data.word;
L
Linus Torvalds 已提交
3310
}
D
David Brownell 已提交
3311
EXPORT_SYMBOL(i2c_smbus_read_word_data);
L
Linus Torvalds 已提交
3312

3313 3314 3315 3316 3317 3318 3319 3320 3321
/**
 * i2c_smbus_write_word_data - SMBus "write word" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @value: 16-bit "word" being written
 *
 * This executes the SMBus "write word" protocol, returning negative errno
 * else zero on success.
 */
3322 3323
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
			      u16 value)
L
Linus Torvalds 已提交
3324 3325 3326
{
	union i2c_smbus_data data;
	data.word = value;
3327 3328 3329
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_WORD_DATA, &data);
L
Linus Torvalds 已提交
3330
}
D
David Brownell 已提交
3331
EXPORT_SYMBOL(i2c_smbus_write_word_data);
L
Linus Torvalds 已提交
3332

D
David Brownell 已提交
3333
/**
3334
 * i2c_smbus_read_block_data - SMBus "block read" protocol
D
David Brownell 已提交
3335
 * @client: Handle to slave device
3336
 * @command: Byte interpreted by slave
D
David Brownell 已提交
3337 3338 3339
 * @values: Byte array into which data will be read; big enough to hold
 *	the data returned by the slave.  SMBus allows at most 32 bytes.
 *
3340 3341
 * This executes the SMBus "block read" protocol, returning negative errno
 * else the number of data bytes in the slave's response.
D
David Brownell 已提交
3342 3343 3344 3345 3346 3347
 *
 * Note that using this function requires that the client's adapter support
 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality.  Not all adapter drivers
 * support this; its emulation through I2C messaging relies on a specific
 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
 */
3348
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
3349 3350 3351
			      u8 *values)
{
	union i2c_smbus_data data;
D
David Brownell 已提交
3352
	int status;
3353

D
David Brownell 已提交
3354 3355 3356 3357 3358
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BLOCK_DATA, &data);
	if (status)
		return status;
3359 3360 3361 3362 3363 3364

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
}
EXPORT_SYMBOL(i2c_smbus_read_block_data);

3365 3366 3367 3368 3369 3370 3371 3372 3373 3374
/**
 * i2c_smbus_write_block_data - SMBus "block write" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @length: Size of data block; SMBus allows at most 32 bytes
 * @values: Byte array which will be written.
 *
 * This executes the SMBus "block write" protocol, returning negative errno
 * else zero on success.
 */
3375
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
3376
			       u8 length, const u8 *values)
L
Linus Torvalds 已提交
3377 3378
{
	union i2c_smbus_data data;
3379

L
Linus Torvalds 已提交
3380 3381 3382
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
3383
	memcpy(&data.block[1], values, length);
3384 3385 3386
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_BLOCK_DATA, &data);
L
Linus Torvalds 已提交
3387
}
D
David Brownell 已提交
3388
EXPORT_SYMBOL(i2c_smbus_write_block_data);
L
Linus Torvalds 已提交
3389 3390

/* Returns the number of read bytes */
3391
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
3392
				  u8 length, u8 *values)
L
Linus Torvalds 已提交
3393 3394
{
	union i2c_smbus_data data;
D
David Brownell 已提交
3395
	int status;
3396

3397 3398 3399
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
D
David Brownell 已提交
3400 3401 3402 3403 3404
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_I2C_BLOCK_DATA, &data);
	if (status < 0)
		return status;
3405 3406 3407

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
L
Linus Torvalds 已提交
3408
}
D
David Brownell 已提交
3409
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
L
Linus Torvalds 已提交
3410

3411
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
3412
				   u8 length, const u8 *values)
3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423
{
	union i2c_smbus_data data;

	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
	memcpy(data.block + 1, values, length);
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_I2C_BLOCK_DATA, &data);
}
D
David Brownell 已提交
3424
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
3425

D
David Brownell 已提交
3426
/* Simulate a SMBus command using the i2c protocol
L
Linus Torvalds 已提交
3427
   No checking of parameters is done!  */
3428 3429 3430 3431
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
				   unsigned short flags,
				   char read_write, u8 command, int size,
				   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
3432 3433 3434 3435 3436
{
	/* So we need to generate a series of msgs. In the case of writing, we
	  need to use only one message; when reading, we need two. We initialize
	  most things with sane defaults, to keep the code below somewhat
	  simpler. */
3437 3438
	unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
	unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
3439
	int num = read_write == I2C_SMBUS_READ ? 2 : 1;
L
Linus Torvalds 已提交
3440
	int i;
3441
	u8 partial_pec = 0;
D
David Brownell 已提交
3442
	int status;
3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455
	struct i2c_msg msg[2] = {
		{
			.addr = addr,
			.flags = flags,
			.len = 1,
			.buf = msgbuf0,
		}, {
			.addr = addr,
			.flags = flags | I2C_M_RD,
			.len = 0,
			.buf = msgbuf1,
		},
	};
L
Linus Torvalds 已提交
3456 3457

	msgbuf0[0] = command;
3458
	switch (size) {
L
Linus Torvalds 已提交
3459 3460 3461
	case I2C_SMBUS_QUICK:
		msg[0].len = 0;
		/* Special case: The read/write field is used as data */
R
Roel Kluin 已提交
3462 3463
		msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
					I2C_M_RD : 0);
L
Linus Torvalds 已提交
3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484
		num = 1;
		break;
	case I2C_SMBUS_BYTE:
		if (read_write == I2C_SMBUS_READ) {
			/* Special case: only a read! */
			msg[0].flags = I2C_M_RD | flags;
			num = 1;
		}
		break;
	case I2C_SMBUS_BYTE_DATA:
		if (read_write == I2C_SMBUS_READ)
			msg[1].len = 1;
		else {
			msg[0].len = 2;
			msgbuf0[1] = data->byte;
		}
		break;
	case I2C_SMBUS_WORD_DATA:
		if (read_write == I2C_SMBUS_READ)
			msg[1].len = 2;
		else {
3485
			msg[0].len = 3;
L
Linus Torvalds 已提交
3486
			msgbuf0[1] = data->word & 0xff;
3487
			msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
3488 3489 3490 3491 3492 3493 3494 3495
		}
		break;
	case I2C_SMBUS_PROC_CALL:
		num = 2; /* Special case */
		read_write = I2C_SMBUS_READ;
		msg[0].len = 3;
		msg[1].len = 2;
		msgbuf0[1] = data->word & 0xff;
3496
		msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
3497 3498 3499
		break;
	case I2C_SMBUS_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
3500 3501 3502
			msg[1].flags |= I2C_M_RECV_LEN;
			msg[1].len = 1; /* block length will be added by
					   the underlying bus driver */
L
Linus Torvalds 已提交
3503 3504 3505
		} else {
			msg[0].len = data->block[0] + 2;
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
D
David Brownell 已提交
3506 3507 3508 3509
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3510
			}
3511
			for (i = 1; i < msg[0].len; i++)
L
Linus Torvalds 已提交
3512 3513 3514 3515
				msgbuf0[i] = data->block[i-1];
		}
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
3516 3517 3518
		num = 2; /* Another special case */
		read_write = I2C_SMBUS_READ;
		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
D
David Brownell 已提交
3519 3520
			dev_err(&adapter->dev,
				"Invalid block write size %d\n",
3521
				data->block[0]);
D
David Brownell 已提交
3522
			return -EINVAL;
3523 3524 3525 3526 3527 3528 3529 3530
		}
		msg[0].len = data->block[0] + 2;
		for (i = 1; i < msg[0].len; i++)
			msgbuf0[i] = data->block[i-1];
		msg[1].flags |= I2C_M_RECV_LEN;
		msg[1].len = 1; /* block length will be added by
				   the underlying bus driver */
		break;
L
Linus Torvalds 已提交
3531 3532
	case I2C_SMBUS_I2C_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
3533
			msg[1].len = data->block[0];
L
Linus Torvalds 已提交
3534 3535
		} else {
			msg[0].len = data->block[0] + 1;
3536
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
D
David Brownell 已提交
3537 3538 3539 3540
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3541 3542 3543 3544 3545 3546
			}
			for (i = 1; i <= data->block[0]; i++)
				msgbuf0[i] = data->block[i];
		}
		break;
	default:
D
David Brownell 已提交
3547 3548
		dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
3549 3550
	}

3551 3552 3553 3554 3555
	i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
				      && size != I2C_SMBUS_I2C_BLOCK_DATA);
	if (i) {
		/* Compute PEC if first message is a write */
		if (!(msg[0].flags & I2C_M_RD)) {
D
David Brownell 已提交
3556
			if (num == 1) /* Write only */
3557 3558 3559 3560 3561 3562
				i2c_smbus_add_pec(&msg[0]);
			else /* Write followed by read */
				partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
		}
		/* Ask for PEC if last message is a read */
		if (msg[num-1].flags & I2C_M_RD)
D
David Brownell 已提交
3563
			msg[num-1].len++;
3564 3565
	}

D
David Brownell 已提交
3566 3567 3568
	status = i2c_transfer(adapter, msg, num);
	if (status < 0)
		return status;
L
Linus Torvalds 已提交
3569

3570 3571
	/* Check PEC if last message is a read */
	if (i && (msg[num-1].flags & I2C_M_RD)) {
D
David Brownell 已提交
3572 3573 3574
		status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
		if (status < 0)
			return status;
3575 3576
	}

L
Linus Torvalds 已提交
3577
	if (read_write == I2C_SMBUS_READ)
3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597
		switch (size) {
		case I2C_SMBUS_BYTE:
			data->byte = msgbuf0[0];
			break;
		case I2C_SMBUS_BYTE_DATA:
			data->byte = msgbuf1[0];
			break;
		case I2C_SMBUS_WORD_DATA:
		case I2C_SMBUS_PROC_CALL:
			data->word = msgbuf1[0] | (msgbuf1[1] << 8);
			break;
		case I2C_SMBUS_I2C_BLOCK_DATA:
			for (i = 0; i < data->block[0]; i++)
				data->block[i+1] = msgbuf1[i];
			break;
		case I2C_SMBUS_BLOCK_DATA:
		case I2C_SMBUS_BLOCK_PROC_CALL:
			for (i = 0; i < msgbuf1[0] + 1; i++)
				data->block[i] = msgbuf1[i];
			break;
L
Linus Torvalds 已提交
3598 3599 3600 3601
		}
	return 0;
}

3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614
/**
 * i2c_smbus_xfer - execute SMBus protocol operations
 * @adapter: Handle to I2C bus
 * @addr: Address of SMBus slave on that bus
 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
 * @command: Byte interpreted by slave, for protocols which use such bytes
 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
 * @data: Data to be read or written
 *
 * This executes an SMBus protocol operation, and returns a negative
 * errno code else zero on success.
 */
Z
Zhenwen Xu 已提交
3615
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3616
		   char read_write, u8 command, int protocol,
Z
Zhenwen Xu 已提交
3617
		   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
3618
{
3619 3620
	unsigned long orig_jiffies;
	int try;
L
Linus Torvalds 已提交
3621 3622
	s32 res;

3623 3624 3625 3626 3627 3628 3629 3630
	/* If enabled, the following two tracepoints are conditional on
	 * read_write and protocol.
	 */
	trace_smbus_write(adapter, addr, flags, read_write,
			  command, protocol, data);
	trace_smbus_read(adapter, addr, flags, read_write,
			 command, protocol);

L
Laurent Pinchart 已提交
3631
	flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
L
Linus Torvalds 已提交
3632 3633

	if (adapter->algo->smbus_xfer) {
3634
		i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647

		/* Retry automatically on arbitration loss */
		orig_jiffies = jiffies;
		for (res = 0, try = 0; try <= adapter->retries; try++) {
			res = adapter->algo->smbus_xfer(adapter, addr, flags,
							read_write, command,
							protocol, data);
			if (res != -EAGAIN)
				break;
			if (time_after(jiffies,
				       orig_jiffies + adapter->timeout))
				break;
		}
3648
		i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
3649

3650
		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3651
			goto trace;
3652 3653 3654 3655 3656 3657
		/*
		 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
		 * implement native support for the SMBus operation.
		 */
	}

3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668
	res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
				      command, protocol, data);

trace:
	/* If enabled, the reply tracepoint is conditional on read_write. */
	trace_smbus_reply(adapter, addr, flags, read_write,
			  command, protocol, data);
	trace_smbus_result(adapter, addr, flags, read_write,
			   command, protocol, res);

	return res;
L
Linus Torvalds 已提交
3669 3670 3671
}
EXPORT_SYMBOL(i2c_smbus_xfer);

3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728
/**
 * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
 * @values: Byte array into which data will be read; big enough to hold
 *	the data returned by the slave.  SMBus allows at most
 *	I2C_SMBUS_BLOCK_MAX bytes.
 *
 * This executes the SMBus "block read" protocol if supported by the adapter.
 * If block read is not supported, it emulates it using either word or byte
 * read protocols depending on availability.
 *
 * The addresses of the I2C slave device that are accessed with this function
 * must be mapped to a linear region, so that a block read will have the same
 * effect as a byte read. Before using this function you must double-check
 * if the I2C slave does support exchanging a block transfer with a byte
 * transfer.
 */
s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
					      u8 command, u8 length, u8 *values)
{
	u8 i = 0;
	int status;

	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;

	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
		return i2c_smbus_read_i2c_block_data(client, command, length, values);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))
		return -EOPNOTSUPP;

	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {
		while ((i + 2) <= length) {
			status = i2c_smbus_read_word_data(client, command + i);
			if (status < 0)
				return status;
			values[i] = status & 0xff;
			values[i + 1] = status >> 8;
			i += 2;
		}
	}

	while (i < length) {
		status = i2c_smbus_read_byte_data(client, command + i);
		if (status < 0)
			return status;
		values[i] = status;
		i++;
	}

	return i;
}
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);

L
Linus Torvalds 已提交
3729 3730 3731
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");