i2c-core.c 86.9 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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   I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
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 */
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#include <dt-bindings/i2c/i2c.h>
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#include <asm/uaccess.h>
#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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/* 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 struct device_type i2c_client_type;
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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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void i2c_transfer_trace_reg(void)
{
	static_key_slow_inc(&i2c_trace_msg);
}

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

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#if defined(CONFIG_ACPI)
struct acpi_i2c_handler_data {
	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 acpi_i2c_lookup {
	struct i2c_board_info *info;
	acpi_handle adapter_handle;
	acpi_handle device_handle;
};
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static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
{
	struct acpi_i2c_lookup *lookup = data;
	struct i2c_board_info *info = lookup->info;
	struct acpi_resource_i2c_serialbus *sb;
	acpi_handle adapter_handle;
	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;

	/*
	 * Extract the ResourceSource and make sure that the handle matches
	 * with the I2C adapter handle.
	 */
	status = acpi_get_handle(lookup->device_handle,
				 sb->resource_source.string_ptr,
				 &adapter_handle);
	if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) {
		info->addr = sb->slave_address;
		if (sb->access_mode == ACPI_I2C_10BIT_MODE)
			info->flags |= I2C_CLIENT_TEN;
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	}

	return 1;
}

static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
				       void *data, void **return_value)
{
	struct i2c_adapter *adapter = data;
	struct list_head resource_list;
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	struct acpi_i2c_lookup lookup;
	struct resource_entry *entry;
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	struct i2c_board_info info;
	struct acpi_device *adev;
	int ret;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;
	if (acpi_bus_get_status(adev) || !adev->status.present)
		return AE_OK;

	memset(&info, 0, sizeof(info));
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	info.fwnode = acpi_fwnode_handle(adev);
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	memset(&lookup, 0, sizeof(lookup));
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	lookup.adapter_handle = ACPI_HANDLE(&adapter->dev);
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	lookup.device_handle = handle;
	lookup.info = &info;

	/*
	 * Look up for I2cSerialBus resource with ResourceSource that
	 * matches with this adapter.
	 */
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	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list,
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				     acpi_i2c_find_address, &lookup);
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	acpi_dev_free_resource_list(&resource_list);

	if (ret < 0 || !info.addr)
		return AE_OK;

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	/* Then fill IRQ number if any */
	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
	if (ret < 0)
		return AE_OK;

	resource_list_for_each_entry(entry, &resource_list) {
		if (resource_type(entry->res) == IORESOURCE_IRQ) {
			info.irq = entry->res->start;
			break;
		}
	}

	acpi_dev_free_resource_list(&resource_list);

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

	return AE_OK;
}

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#define ACPI_I2C_MAX_SCAN_DEPTH 32

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/**
 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
 * @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.
 */
static void acpi_i2c_register_devices(struct i2c_adapter *adap)
{
	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,
				     ACPI_I2C_MAX_SCAN_DEPTH,
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				     acpi_i2c_add_device, NULL,
				     adap, NULL);
	if (ACPI_FAILURE(status))
		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
}

#else /* CONFIG_ACPI */
static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
#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
acpi_i2c_space_handler(u32 function, acpi_physical_address command,
			u32 bits, u64 *value64,
			void *handler_context, void *region_context)
{
	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
	struct acpi_i2c_handler_data *data = handler_context;
	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 {
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			status = i2c_smbus_write_block_data(client, command,
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					gsb->len, gsb->data);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
		if (action == ACPI_READ) {
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			status = acpi_gsb_i2c_read_bytes(client, command,
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					gsb->data, info->access_length);
			if (status > 0)
				status = 0;
		} else {
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			status = acpi_gsb_i2c_write_bytes(client, command,
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					gsb->data, info->access_length);
		}
		break;

	default:
		pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	gsb->status = status;

 err:
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	kfree(client);
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	ACPI_FREE(ares);
	return ret;
}


static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
{
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	acpi_handle handle;
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	struct acpi_i2c_handler_data *data;
	acpi_status status;

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	if (!adapter->dev.parent)
		return -ENODEV;

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

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	if (!handle)
		return -ENODEV;

	data = kzalloc(sizeof(struct acpi_i2c_handler_data),
			    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,
				&acpi_i2c_space_handler,
				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;
	}

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	acpi_walk_dep_device_list(handle);
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	return 0;
}

static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
{
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	acpi_handle handle;
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	struct acpi_i2c_handler_data *data;
	acpi_status status;

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	if (!adapter->dev.parent)
		return;

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

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	if (!handle)
		return;

	acpi_remove_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
				&acpi_i2c_space_handler);

	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 */
static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
{ }

static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
{ return 0; }
#endif /* CONFIG_ACPI_I2C_OPREGION */

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/* ------------------------------------------------------------------------- */

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static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
						const struct i2c_client *client)
{
	while (id->name[0]) {
		if (strcmp(client->name, id->name) == 0)
			return id;
		id++;
	}
	return NULL;
}

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static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
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	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;

	if (!client)
		return 0;
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	/* Attempt an OF style match */
	if (of_driver_match_device(dev, drv))
		return 1;

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

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	driver = to_i2c_driver(drv);
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	/* match on an id table if there is one */
	if (driver->id_table)
		return i2c_match_id(driver->id_table, client) != NULL;

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	return 0;
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}

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/* uevent helps with hotplug: modprobe -q $(MODALIAS) */
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static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
	struct i2c_client	*client = to_i2c_client(dev);
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	int rc;

	rc = acpi_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;
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	if (add_uevent_var(env, "MODALIAS=%s%s",
			   I2C_MODULE_PREFIX, client->name))
		return -ENOMEM;
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	dev_dbg(dev, "uevent\n");
	return 0;
}

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/* 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)
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		bri->prepare_recovery(adap);
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	bri->set_scl(adap, val);
	ndelay(RECOVERY_NDELAY);

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	/*
	 * 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)
639
		bri->unprepare_recovery(adap);
640 641 642 643 644 645 646 647

	return ret;
}

int i2c_generic_scl_recovery(struct i2c_adapter *adap)
{
	return i2c_generic_recovery(adap);
}
648
EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
649 650 651 652 653 654 655 656 657 658 659 660 661 662

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;
}
663
EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
664 665 666 667 668 669 670 671 672

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);
}
673
EXPORT_SYMBOL_GPL(i2c_recover_bus);
674

675
static int i2c_device_probe(struct device *dev)
L
Linus Torvalds 已提交
676
{
677 678
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
679
	int status;
D
David Brownell 已提交
680

681 682 683
	if (!client)
		return 0;

684 685 686
	if (!client->irq) {
		int irq = -ENOENT;

687 688 689 690 691
		if (dev->of_node) {
			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)) {
692
			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
693
		}
694
		if (irq == -EPROBE_DEFER)
695
			return irq;
696 697
		if (irq < 0)
			irq = 0;
698 699 700 701

		client->irq = irq;
	}

702
	driver = to_i2c_driver(dev->driver);
J
Jean Delvare 已提交
703
	if (!driver->probe || !driver->id_table)
D
David Brownell 已提交
704
		return -ENODEV;
705

706 707 708 709 710 711 712 713 714 715 716 717 718 719
	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
720
			status = dev_pm_set_wake_irq(dev, client->irq);
721 722 723 724 725 726 727
		else
			status = 0;

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

D
David Brownell 已提交
728
	dev_dbg(dev, "probe\n");
729

730 731
	status = of_clk_set_defaults(dev->of_node, false);
	if (status < 0)
732
		goto err_clear_wakeup_irq;
733

734
	status = dev_pm_domain_attach(&client->dev, true);
735 736 737 738 739 740
	if (status == -EPROBE_DEFER)
		goto err_clear_wakeup_irq;

	status = driver->probe(client, i2c_match_id(driver->id_table, client));
	if (status)
		goto err_detach_pm_domain;
741

742 743 744 745 746 747 748
	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);
749
	return status;
750
}
L
Linus Torvalds 已提交
751

752 753
static int i2c_device_remove(struct device *dev)
{
754
	struct i2c_client	*client = i2c_verify_client(dev);
D
David Brownell 已提交
755
	struct i2c_driver	*driver;
756
	int status = 0;
D
David Brownell 已提交
757

758
	if (!client || !dev->driver)
D
David Brownell 已提交
759 760 761 762 763 764 765
		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	}
766

767
	dev_pm_domain_detach(&client->dev, true);
768 769 770 771

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

D
David Brownell 已提交
772
	return status;
L
Linus Torvalds 已提交
773 774
}

775
static void i2c_device_shutdown(struct device *dev)
L
Linus Torvalds 已提交
776
{
777
	struct i2c_client *client = i2c_verify_client(dev);
778 779
	struct i2c_driver *driver;

780
	if (!client || !dev->driver)
781 782 783
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
784
		driver->shutdown(client);
L
Linus Torvalds 已提交
785 786
}

787 788 789 790 791
static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

Z
Zhenwen Xu 已提交
792
static ssize_t
793
show_name(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
794
{
795 796
	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
797
}
798
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
D
David Brownell 已提交
799

Z
Zhenwen Xu 已提交
800 801
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
802 803
{
	struct i2c_client *client = to_i2c_client(dev);
804 805 806 807 808 809
	int len;

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

810
	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
811
}
812 813 814 815
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
816
	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
817 818 819
	&dev_attr_modalias.attr,
	NULL
};
820
ATTRIBUTE_GROUPS(i2c_dev);
821

J
Jon Smirl 已提交
822
struct bus_type i2c_bus_type = {
823 824 825 826 827
	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
828
};
J
Jon Smirl 已提交
829
EXPORT_SYMBOL_GPL(i2c_bus_type);
830

831
static struct device_type i2c_client_type = {
832
	.groups		= i2c_dev_groups,
833 834 835 836
	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};

837 838 839 840 841 842 843 844 845 846 847 848

/**
 * 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)
{
849
	return (dev->type == &i2c_client_type)
850 851 852 853 854 855
			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


856 857 858 859 860 861 862 863 864 865 866 867 868 869 870
/* 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;
}

871
/* This is a permissive address validity check, I2C address map constraints
L
Lucas De Marchi 已提交
872
 * are purposely not enforced, except for the general call address. */
873
static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
874
{
875
	if (flags & I2C_CLIENT_TEN) {
876
		/* 10-bit address, all values are valid */
877
		if (addr > 0x3ff)
878 879 880
			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
881
		if (addr == 0x00 || addr > 0x7f)
882 883 884 885 886
			return -EINVAL;
	}
	return 0;
}

887 888 889 890
/* 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. */
891
static int i2c_check_7bit_addr_validity_strict(unsigned short addr)
892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907
{
	/*
	 * 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;
}

908 909 910 911 912
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

913
	if (client && i2c_encode_flags_to_addr(client) == addr)
914 915 916 917
		return -EBUSY;
	return 0;
}

918 919 920
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
921
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
922 923 924 925 926
	int result;

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

927 928
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946

	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;
}

947 948
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
949
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
950 951
	int result = 0;

952 953
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
954 955 956 957 958 959

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

	return result;
960 961
}

962 963 964 965 966 967
/**
 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
 * @adapter: Target I2C bus segment
 */
void i2c_lock_adapter(struct i2c_adapter *adapter)
{
968 969 970 971
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)
		i2c_lock_adapter(parent);
972 973
	else
		rt_mutex_lock(&adapter->bus_lock);
974 975 976 977 978 979 980 981 982
}
EXPORT_SYMBOL_GPL(i2c_lock_adapter);

/**
 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
 * @adapter: Target I2C bus segment
 */
static int i2c_trylock_adapter(struct i2c_adapter *adapter)
{
983 984 985 986
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)
		return i2c_trylock_adapter(parent);
987 988
	else
		return rt_mutex_trylock(&adapter->bus_lock);
989 990 991 992 993 994 995 996
}

/**
 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
 * @adapter: Target I2C bus segment
 */
void i2c_unlock_adapter(struct i2c_adapter *adapter)
{
997 998 999 1000
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)
		i2c_unlock_adapter(parent);
1001 1002
	else
		rt_mutex_unlock(&adapter->bus_lock);
1003 1004 1005
}
EXPORT_SYMBOL_GPL(i2c_unlock_adapter);

1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
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),
1017
		     i2c_encode_flags_to_addr(client));
1018 1019
}

1020
/**
1021
 * i2c_new_device - instantiate an i2c device
1022 1023
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
1024
 * Context: can sleep
1025
 *
1026 1027 1028 1029 1030 1031
 * 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.
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048
 *
 * 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;
1049

A
Anton Vorontsov 已提交
1050 1051 1052
	if (info->archdata)
		client->dev.archdata = *info->archdata;

M
Marc Pignat 已提交
1053
	client->flags = info->flags;
1054 1055 1056 1057 1058
	client->addr = info->addr;
	client->irq = info->irq;

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

1059
	status = i2c_check_addr_validity(client->addr, client->flags);
1060 1061 1062 1063 1064 1065
	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;
	}

1066
	/* Check for address business */
1067
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1068 1069 1070 1071 1072
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
1073
	client->dev.type = &i2c_client_type;
1074
	client->dev.of_node = info->of_node;
1075
	client->dev.fwnode = info->fwnode;
1076

1077
	i2c_dev_set_name(adap, client);
1078 1079 1080 1081 1082 1083 1084
	status = device_register(&client->dev);
	if (status)
		goto out_err;

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

1085
	return client;
1086 1087 1088 1089

out_err:
	dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
		"(%d)\n", client->name, client->addr, status);
1090
out_err_silent:
1091 1092
	kfree(client);
	return NULL;
1093 1094 1095 1096 1097 1098 1099
}
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
1100
 * Context: can sleep
1101 1102
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
1103
{
1104 1105
	if (client->dev.of_node)
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
D
David Brownell 已提交
1106 1107
	device_unregister(&client->dev);
}
1108
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
1109 1110


J
Jean Delvare 已提交
1111 1112 1113 1114 1115
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

1116 1117 1118 1119 1120 1121 1122
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
1123 1124 1125 1126 1127 1128
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
1129 1130
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
1131
	.id_table	= dummy_id,
1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
};

/**
 * 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
1152
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1153 1154
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
1155
		I2C_BOARD_INFO("dummy", address),
1156 1157 1158 1159 1160 1161
	};

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

1162 1163
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
1164 1165
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
1166
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
1167
{
1168
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
1169 1170 1171
	complete(&adap->dev_released);
}

1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
/*
 * This function is only needed for mutex_lock_nested, so it is never
 * called unless locking correctness checking is enabled. Thus we
 * make it inline to avoid a compiler warning. That's what gcc ends up
 * doing anyway.
 */
static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
{
	unsigned int depth = 0;

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

	return depth;
}

1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231
/*
 * 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;
	}

1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
	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;
	}

1242 1243
	client = i2c_new_device(adap, &info);
	if (!client)
1244
		return -EINVAL;
1245 1246

	/* Keep track of the added device */
1247
	mutex_lock(&adap->userspace_clients_lock);
1248
	list_add_tail(&client->detected, &adap->userspace_clients);
1249
	mutex_unlock(&adap->userspace_clients_lock);
1250 1251 1252 1253 1254
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1255
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288

/*
 * 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;
1289 1290
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1291 1292
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1293
		if (i2c_encode_flags_to_addr(client) == addr) {
1294 1295 1296 1297 1298 1299 1300 1301 1302
			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;
		}
	}
1303
	mutex_unlock(&adap->userspace_clients_lock);
1304 1305 1306 1307 1308 1309

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1310 1311
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1312 1313 1314 1315 1316 1317 1318

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1319
ATTRIBUTE_GROUPS(i2c_adapter);
1320

1321
struct device_type i2c_adapter_type = {
1322
	.groups		= i2c_adapter_groups,
1323
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1324
};
1325
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1326

1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343
/**
 * 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);

1344 1345 1346 1347
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1348 1349 1350 1351
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1352
	down_read(&__i2c_board_lock);
1353 1354 1355 1356
	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
1357 1358
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1359 1360
				devinfo->board_info.addr);
	}
1361
	up_read(&__i2c_board_lock);
1362 1363
}

1364 1365 1366
/* OF support code */

#if IS_ENABLED(CONFIG_OF)
1367 1368
static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
						 struct device_node *node)
1369
{
1370 1371 1372
	struct i2c_client *result;
	struct i2c_board_info info = {};
	struct dev_archdata dev_ad = {};
W
Wolfram Sang 已提交
1373 1374
	const __be32 *addr_be;
	u32 addr;
1375
	int len;
1376

1377
	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1378

1379 1380 1381 1382 1383
	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);
	}
1384

W
Wolfram Sang 已提交
1385 1386
	addr_be = of_get_property(node, "reg", &len);
	if (!addr_be || (len < sizeof(*addr_be))) {
1387 1388 1389 1390
		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1391

W
Wolfram Sang 已提交
1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
	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)) {
1404 1405 1406 1407
		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
			info.addr, node->full_name);
		return ERR_PTR(-EINVAL);
	}
1408

W
Wolfram Sang 已提交
1409
	info.addr = addr;
1410 1411
	info.of_node = of_node_get(node);
	info.archdata = &dev_ad;
1412

1413 1414
	if (of_get_property(node, "wakeup-source", NULL))
		info.flags |= I2C_CLIENT_WAKE;
1415

1416 1417 1418 1419 1420 1421 1422 1423 1424
	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;
}
1425

1426 1427 1428
static void of_i2c_register_devices(struct i2c_adapter *adap)
{
	struct device_node *node;
1429

1430 1431 1432
	/* Only register child devices if the adapter has a node pointer set */
	if (!adap->dev.of_node)
		return;
1433

1434 1435
	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");

1436 1437 1438
	for_each_available_child_of_node(adap->dev.of_node, node) {
		if (of_node_test_and_set_flag(node, OF_POPULATED))
			continue;
1439
		of_i2c_register_device(adap, node);
1440
	}
1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451
}

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;
1452
	struct i2c_client *client;
1453

1454
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1455 1456 1457
	if (!dev)
		return NULL;

1458 1459 1460 1461 1462
	client = i2c_verify_client(dev);
	if (!client)
		put_device(dev);

	return client;
1463 1464 1465 1466 1467 1468 1469
}
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;
1470
	struct i2c_adapter *adapter;
1471

1472
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1473 1474 1475
	if (!dev)
		return NULL;

1476 1477 1478 1479 1480
	adapter = i2c_verify_adapter(dev);
	if (!adapter)
		put_device(dev);

	return adapter;
1481 1482
}
EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500

/* 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);
1501 1502 1503 1504
#else
static void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif /* CONFIG_OF */

J
Jean Delvare 已提交
1505 1506
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1507
{
1508 1509 1510 1511
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

	/* Let legacy drivers scan this bus for matching devices */
1512
	if (driver->attach_adapter) {
J
Jean Delvare 已提交
1513 1514
		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
			 driver->driver.name);
1515 1516
		dev_warn(&adap->dev, "Please use another way to instantiate "
			 "your i2c_client\n");
1517 1518 1519 1520 1521 1522
		/* We ignore the return code; if it fails, too bad */
		driver->attach_adapter(adap);
	}
	return 0;
}

J
Jean Delvare 已提交
1523 1524 1525 1526 1527
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1528
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1529
{
J
Jean Delvare 已提交
1530
	int res = 0;
L
Linus Torvalds 已提交
1531

1532
	/* Can't register until after driver model init */
1533
	if (WARN_ON(!is_registered)) {
1534 1535 1536
		res = -EAGAIN;
		goto out_list;
	}
1537

1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549
	/* Sanity checks */
	if (unlikely(adap->name[0] == '\0')) {
		pr_err("i2c-core: Attempt to register an adapter with "
		       "no name!\n");
		return -EINVAL;
	}
	if (unlikely(!adap->algo)) {
		pr_err("i2c-core: Attempt to register adapter '%s' with "
		       "no algo!\n", adap->name);
		return -EINVAL;
	}

1550
	rt_mutex_init(&adap->bus_lock);
1551
	mutex_init(&adap->userspace_clients_lock);
1552
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
1553

1554 1555 1556 1557
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

1558
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1559 1560
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
1561 1562 1563
	res = device_register(&adap->dev);
	if (res)
		goto out_list;
L
Linus Torvalds 已提交
1564

1565 1566
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

1567
	pm_runtime_no_callbacks(&adap->dev);
1568
	pm_runtime_enable(&adap->dev);
1569

1570 1571 1572 1573 1574 1575 1576 1577
#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

1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610
	/* bus recovery specific initialization */
	if (adap->bus_recovery_info) {
		struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;

		if (!bri->recover_bus) {
			dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
			adap->bus_recovery_info = NULL;
			goto exit_recovery;
		}

		/* Generic GPIO recovery */
		if (bri->recover_bus == i2c_generic_gpio_recovery) {
			if (!gpio_is_valid(bri->scl_gpio)) {
				dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
				adap->bus_recovery_info = NULL;
				goto exit_recovery;
			}

			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->set_scl || !bri->get_scl) {
			/* Generic SCL recovery */
			dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
			adap->bus_recovery_info = NULL;
		}
	}

exit_recovery:
1611
	/* create pre-declared device nodes */
1612
	of_i2c_register_devices(adap);
1613
	acpi_i2c_register_devices(adap);
1614
	acpi_i2c_install_space_handler(adap);
1615

1616 1617 1618
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

1619
	/* Notify drivers */
1620
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
1621
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
1622
	mutex_unlock(&core_lock);
1623 1624

	return 0;
1625 1626

out_list:
1627
	mutex_lock(&core_lock);
1628
	idr_remove(&i2c_adapter_idr, adap->nr);
1629 1630
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
1631 1632
}

1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653
/**
 * __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)
{
	int	id;

	mutex_lock(&core_lock);
	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
		       GFP_KERNEL);
	mutex_unlock(&core_lock);
	if (id < 0)
		return id == -ENOSPC ? -EBUSY : id;

	return i2c_register_adapter(adap);
}

1654 1655 1656
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
1657
 * Context: can sleep
1658 1659
 *
 * This routine is used to declare an I2C adapter when its bus number
1660 1661 1662
 * 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.
1663 1664 1665 1666 1667 1668 1669
 *
 * 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)
{
1670
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
1671
	int id;
1672

1673 1674 1675 1676 1677 1678 1679 1680
	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
1681
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
1682 1683
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
1684
	mutex_unlock(&core_lock);
T
Tejun Heo 已提交
1685 1686
	if (id < 0)
		return id;
1687 1688

	adapter->nr = id;
T
Tejun Heo 已提交
1689

1690 1691 1692 1693 1694 1695 1696
	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
1697
 * Context: can sleep
1698 1699
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
1700 1701
 * 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
1702 1703
 * is used to properly configure I2C devices.
 *
1704 1705 1706
 * 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.
 *
1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718
 * 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)
{
1719 1720
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
1721

1722
	return __i2c_add_numbered_adapter(adap);
1723 1724 1725
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
1726
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
1727
			      struct i2c_adapter *adapter)
1728
{
1729
	struct i2c_client *client, *_n;
1730

1731 1732
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
1733 1734 1735 1736 1737 1738 1739 1740
	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);
		}
	}
1741 1742
}

1743
static int __unregister_client(struct device *dev, void *dummy)
1744 1745 1746 1747 1748 1749 1750 1751
{
	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)
1752 1753 1754 1755 1756 1757 1758
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client)
		i2c_unregister_device(client);
	return 0;
}

J
Jean Delvare 已提交
1759 1760
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
1761 1762
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
1763 1764
}

D
David Brownell 已提交
1765 1766 1767 1768 1769 1770 1771 1772
/**
 * 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.
 */
1773
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1774
{
1775
	struct i2c_adapter *found;
1776
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
1777 1778

	/* First make sure that this adapter was ever added */
1779 1780 1781 1782
	mutex_lock(&core_lock);
	found = idr_find(&i2c_adapter_idr, adap->nr);
	mutex_unlock(&core_lock);
	if (found != adap) {
1783 1784
		pr_debug("i2c-core: attempting to delete unregistered "
			 "adapter [%s]\n", adap->name);
1785
		return;
L
Linus Torvalds 已提交
1786 1787
	}

1788
	acpi_i2c_remove_space_handler(adap);
1789
	/* Tell drivers about this removal */
1790
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
1791
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
1792
			       __process_removed_adapter);
1793
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1794

1795
	/* Remove devices instantiated from sysfs */
1796 1797
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1798 1799 1800 1801 1802 1803
	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);
1804
	}
1805
	mutex_unlock(&adap->userspace_clients_lock);
1806

1807
	/* Detach any active clients. This can't fail, thus we do not
1808 1809 1810 1811
	 * 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
1812 1813
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
1814

1815 1816 1817 1818 1819
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

1820 1821 1822
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

1823 1824
	pm_runtime_disable(&adap->dev);

1825 1826 1827 1828 1829
	/* 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
1830
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1831
	 */
L
Linus Torvalds 已提交
1832 1833 1834 1835
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

1836
	/* free bus id */
1837
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
1838
	idr_remove(&i2c_adapter_idr, adap->nr);
1839
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1840

1841 1842 1843
	/* 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
1844
}
D
David Brownell 已提交
1845
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
1846

1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898
/**
 * 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
1899 1900
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912
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
1913
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
1914
{
1915 1916
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
1917
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
1918 1919
}

D
David Brownell 已提交
1920 1921
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1922
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
1923 1924
 */

1925
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
1926
{
1927
	int res;
L
Linus Torvalds 已提交
1928

1929
	/* Can't register until after driver model init */
1930
	if (WARN_ON(!is_registered))
1931 1932
		return -EAGAIN;

L
Linus Torvalds 已提交
1933
	/* add the driver to the list of i2c drivers in the driver core */
1934
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
1935 1936
	driver->driver.bus = &i2c_bus_type;

1937
	/* When registration returns, the driver core
1938 1939
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
1940 1941
	res = driver_register(&driver->driver);
	if (res)
1942
		return res;
D
David Brownell 已提交
1943

1944
	pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
1945

1946 1947
	INIT_LIST_HEAD(&driver->clients);
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
1948
	i2c_for_each_dev(driver, __process_new_driver);
1949

D
Dave Young 已提交
1950 1951 1952 1953
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
1954
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
1955
{
L
Lars-Peter Clausen 已提交
1956 1957 1958
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
1959 1960
}

D
David Brownell 已提交
1961 1962 1963
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
1964
 * Context: can sleep
D
David Brownell 已提交
1965
 */
1966
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
1967
{
J
Jean Delvare 已提交
1968
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
1969 1970

	driver_unregister(&driver->driver);
1971
	pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
1972
}
D
David Brownell 已提交
1973
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
1974

D
David Brownell 已提交
1975 1976
/* ------------------------------------------------------------------------- */

1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
/**
 * 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
1989
{
1990 1991 1992
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
1993
}
D
David Brownell 已提交
1994
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
1995

1996 1997 1998 1999 2000 2001 2002
/**
 * 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
2003
{
2004 2005
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
2006
}
D
David Brownell 已提交
2007
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
2008

2009 2010 2011 2012 2013 2014 2015 2016 2017
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;
2018 2019 2020 2021
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
2022

2023 2024 2025
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
2026 2027 2028
	return 0;
}

L
Linus Torvalds 已提交
2029 2030
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
2031
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
2032

2033 2034 2035
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
2036
}
D
David Brownell 已提交
2037
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
2038

2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052
#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 */

2053 2054 2055 2056 2057
		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
			put_device(&adap->dev);
			return NOTIFY_OK;
		}

2058 2059 2060 2061 2062 2063 2064 2065 2066 2067
		client = of_i2c_register_device(adap, rd->dn);
		put_device(&adap->dev);

		if (IS_ERR(client)) {
			pr_err("%s: failed to create for '%s'\n",
					__func__, rd->dn->full_name);
			return notifier_from_errno(PTR_ERR(client));
		}
		break;
	case OF_RECONFIG_CHANGE_REMOVE:
2068 2069 2070 2071
		/* already depopulated? */
		if (!of_node_check_flag(rd->dn, OF_POPULATED))
			return NOTIFY_OK;

2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093
		/* 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
2094 2095 2096 2097
static int __init i2c_init(void)
{
	int retval;

2098 2099 2100 2101 2102 2103 2104
	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
2105 2106 2107
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
2108 2109 2110 2111 2112 2113 2114
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
2115 2116
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
2117
		goto class_err;
2118 2119 2120 2121

	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));

2122
	is_registered = true;
2123 2124
	return 0;

2125 2126 2127
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
2128
bus_err:
2129
#endif
2130 2131
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
2132 2133 2134 2135
}

static void __exit i2c_exit(void)
{
2136 2137
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2138
	i2c_del_driver(&dummy_driver);
2139 2140 2141
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
2142
	bus_unregister(&i2c_bus_type);
2143
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
2144 2145
}

D
David Brownell 已提交
2146 2147 2148 2149
/* 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
2150 2151 2152 2153 2154 2155 2156
module_exit(i2c_exit);

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

W
Wolfram Sang 已提交
2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215
/* 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;
}

2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232
/**
 * __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
2233 2234 2235
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248
	/* 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);
	}

2249 2250 2251 2252 2253 2254 2255 2256 2257 2258
	/* 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;
	}

2259 2260 2261 2262 2263 2264 2265 2266
	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);
	}

2267 2268 2269 2270
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282
/**
 * 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
2283
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
2284
{
2285
	int ret;
L
Linus Torvalds 已提交
2286

2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303
	/* 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
2304 2305 2306 2307
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
			dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
2308 2309 2310
				"len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
				? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
L
Linus Torvalds 已提交
2311 2312 2313
		}
#endif

2314
		if (in_atomic() || irqs_disabled()) {
2315
			ret = i2c_trylock_adapter(adap);
2316 2317 2318 2319
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
2320
			i2c_lock_adapter(adap);
2321 2322
		}

2323
		ret = __i2c_transfer(adap, msgs, num);
2324
		i2c_unlock_adapter(adap);
L
Linus Torvalds 已提交
2325 2326 2327 2328

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
2329
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
2330 2331
	}
}
D
David Brownell 已提交
2332
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
2333

2334 2335 2336 2337
/**
 * 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
2338
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2339 2340 2341
 *
 * Returns negative errno, or else the number of bytes written.
 */
2342
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
L
Linus Torvalds 已提交
2343 2344
{
	int ret;
2345
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2346 2347
	struct i2c_msg msg;

2348 2349 2350 2351
	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = (char *)buf;
D
David Brownell 已提交
2352

2353
	ret = i2c_transfer(adap, &msg, 1);
L
Linus Torvalds 已提交
2354

2355 2356 2357 2358
	/*
	 * If everything went ok (i.e. 1 msg transmitted), return #bytes
	 * transmitted, else error code.
	 */
2359
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2360
}
D
David Brownell 已提交
2361
EXPORT_SYMBOL(i2c_master_send);
L
Linus Torvalds 已提交
2362

2363 2364 2365 2366
/**
 * 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
2367
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2368 2369 2370
 *
 * Returns negative errno, or else the number of bytes read.
 */
2371
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
L
Linus Torvalds 已提交
2372
{
2373
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2374 2375
	struct i2c_msg msg;
	int ret;
2376 2377 2378 2379 2380 2381 2382 2383 2384

	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);

2385 2386 2387 2388
	/*
	 * If everything went ok (i.e. 1 msg received), return #bytes received,
	 * else error code.
	 */
2389
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2390
}
D
David Brownell 已提交
2391
EXPORT_SYMBOL(i2c_master_recv);
L
Linus Torvalds 已提交
2392 2393 2394 2395 2396 2397 2398

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

2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422
/*
 * 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
2423 2424
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2425 2426
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2427 2428 2429 2430
	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 {
2431 2432
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2433 2434
		err = -EOPNOTSUPP;
	}
2435 2436 2437 2438

	return err >= 0;
}

J
Jean Delvare 已提交
2439
static int i2c_detect_address(struct i2c_client *temp_client,
2440 2441 2442 2443 2444 2445 2446 2447
			      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 */
2448
	err = i2c_check_7bit_addr_validity_strict(addr);
2449
	if (err) {
2450 2451
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2452
		return err;
2453 2454
	}

2455
	/* Skip if already in use (7 bit, no need to encode flags) */
2456
	if (i2c_check_addr_busy(adapter, addr))
2457 2458
		return 0;

J
Jean Delvare 已提交
2459
	/* Make sure there is something at this address */
2460 2461
	if (!i2c_default_probe(adapter, addr))
		return 0;
2462 2463 2464 2465

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
2466
	err = driver->detect(temp_client, &info);
2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481
	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') {
		dev_err(&adapter->dev, "%s detection function provided "
			"no name for 0x%x\n", driver->driver.name,
			addr);
	} else {
		struct i2c_client *client;

		/* Detection succeeded, instantiate the device */
2482 2483 2484 2485 2486 2487 2488
		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);

2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502
		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)
{
2503
	const unsigned short *address_list;
2504 2505 2506 2507
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

2508 2509
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
2510 2511
		return 0;

2512 2513 2514 2515 2516 2517 2518 2519 2520 2521
	/* Warn that the adapter lost class based instantiation */
	if (adapter->class == I2C_CLASS_DEPRECATED) {
		dev_dbg(&adapter->dev,
			"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",
			driver->driver.name);
		return 0;
	}

J
Jean Delvare 已提交
2522 2523 2524 2525
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

2526 2527 2528 2529 2530 2531
	/* 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;

2532
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2533
		dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2534 2535
			"addr 0x%02x\n", adap_id, address_list[i]);
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
2536
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
2537 2538
		if (unlikely(err))
			break;
2539 2540 2541 2542 2543 2544
	}

	kfree(temp_client);
	return err;
}

2545 2546 2547 2548 2549 2550 2551
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
2552 2553 2554
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
2555 2556
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
2557 2558 2559
{
	int i;

2560
	if (!probe)
2561
		probe = i2c_default_probe;
J
Jean Delvare 已提交
2562 2563 2564

	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
2565
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
J
Jean Delvare 已提交
2566 2567 2568 2569 2570
			dev_warn(&adap->dev, "Invalid 7-bit address "
				 "0x%02x\n", addr_list[i]);
			continue;
		}

2571
		/* Check address availability (7 bit, no need to encode flags) */
2572
		if (i2c_check_addr_busy(adap, addr_list[i])) {
J
Jean Delvare 已提交
2573 2574 2575 2576 2577
			dev_dbg(&adap->dev, "Address 0x%02x already in "
				"use, not probing\n", addr_list[i]);
			continue;
		}

2578
		/* Test address responsiveness */
2579
		if (probe(adap, addr_list[i]))
2580
			break;
J
Jean Delvare 已提交
2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592
	}

	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);

2593
struct i2c_adapter *i2c_get_adapter(int nr)
L
Linus Torvalds 已提交
2594 2595
{
	struct i2c_adapter *adapter;
D
David Brownell 已提交
2596

J
Jean Delvare 已提交
2597
	mutex_lock(&core_lock);
2598
	adapter = idr_find(&i2c_adapter_idr, nr);
2599 2600 2601 2602 2603 2604
	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
2605 2606
		adapter = NULL;

2607
 exit:
J
Jean Delvare 已提交
2608
	mutex_unlock(&core_lock);
2609
	return adapter;
L
Linus Torvalds 已提交
2610
}
D
David Brownell 已提交
2611
EXPORT_SYMBOL(i2c_get_adapter);
L
Linus Torvalds 已提交
2612 2613 2614

void i2c_put_adapter(struct i2c_adapter *adap)
{
2615 2616 2617 2618 2619
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
L
Linus Torvalds 已提交
2620
}
D
David Brownell 已提交
2621
EXPORT_SYMBOL(i2c_put_adapter);
L
Linus Torvalds 已提交
2622 2623 2624

/* The SMBus parts */

D
David Brownell 已提交
2625
#define POLY    (0x1070U << 3)
Z
Zhenwen Xu 已提交
2626
static u8 crc8(u16 data)
L
Linus Torvalds 已提交
2627 2628
{
	int i;
D
David Brownell 已提交
2629

2630
	for (i = 0; i < 8; i++) {
D
David Brownell 已提交
2631
		if (data & 0x8000)
L
Linus Torvalds 已提交
2632 2633 2634 2635 2636 2637
			data = data ^ POLY;
		data = data << 1;
	}
	return (u8)(data >> 8);
}

2638 2639
/* 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
2640 2641 2642
{
	int i;

2643
	for (i = 0; i < count; i++)
2644
		crc = crc8((crc ^ p[i]) << 8);
L
Linus Torvalds 已提交
2645 2646 2647
	return crc;
}

2648 2649
/* 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
2650
{
2651 2652 2653 2654 2655 2656
	/* The address will be sent first */
	u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
	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
2657 2658
}

2659 2660
/* Used for write only transactions */
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
L
Linus Torvalds 已提交
2661
{
2662 2663
	msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
	msg->len++;
L
Linus Torvalds 已提交
2664 2665
}

2666 2667 2668 2669 2670 2671
/* 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
2672
{
2673 2674
	u8 rpec = msg->buf[--msg->len];
	cpec = i2c_smbus_msg_pec(cpec, msg);
L
Linus Torvalds 已提交
2675 2676 2677 2678

	if (rpec != cpec) {
		pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
			rpec, cpec);
D
David Brownell 已提交
2679
		return -EBADMSG;
L
Linus Torvalds 已提交
2680
	}
D
David Brownell 已提交
2681
	return 0;
L
Linus Torvalds 已提交
2682 2683
}

2684 2685 2686 2687 2688 2689 2690
/**
 * 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.
 */
2691
s32 i2c_smbus_read_byte(const struct i2c_client *client)
L
Linus Torvalds 已提交
2692 2693
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2694 2695 2696 2697 2698 2699
	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
2700
}
D
David Brownell 已提交
2701
EXPORT_SYMBOL(i2c_smbus_read_byte);
L
Linus Torvalds 已提交
2702

2703 2704 2705 2706 2707 2708 2709 2710
/**
 * 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.
 */
2711
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
L
Linus Torvalds 已提交
2712
{
2713
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2714
	                      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
L
Linus Torvalds 已提交
2715
}
D
David Brownell 已提交
2716
EXPORT_SYMBOL(i2c_smbus_write_byte);
L
Linus Torvalds 已提交
2717

2718 2719 2720 2721 2722 2723 2724 2725
/**
 * 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.
 */
2726
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2727 2728
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2729 2730 2731 2732 2733 2734
	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
2735
}
D
David Brownell 已提交
2736
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
L
Linus Torvalds 已提交
2737

2738 2739 2740 2741 2742 2743 2744 2745 2746
/**
 * 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.
 */
2747 2748
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
			      u8 value)
L
Linus Torvalds 已提交
2749 2750 2751
{
	union i2c_smbus_data data;
	data.byte = value;
2752 2753 2754
	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
2755
}
D
David Brownell 已提交
2756
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
L
Linus Torvalds 已提交
2757

2758 2759 2760 2761 2762 2763 2764 2765
/**
 * 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.
 */
2766
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2767 2768
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2769 2770 2771 2772 2773 2774
	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
2775
}
D
David Brownell 已提交
2776
EXPORT_SYMBOL(i2c_smbus_read_word_data);
L
Linus Torvalds 已提交
2777

2778 2779 2780 2781 2782 2783 2784 2785 2786
/**
 * 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.
 */
2787 2788
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
			      u16 value)
L
Linus Torvalds 已提交
2789 2790 2791
{
	union i2c_smbus_data data;
	data.word = value;
2792 2793 2794
	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
2795
}
D
David Brownell 已提交
2796
EXPORT_SYMBOL(i2c_smbus_write_word_data);
L
Linus Torvalds 已提交
2797

D
David Brownell 已提交
2798
/**
2799
 * i2c_smbus_read_block_data - SMBus "block read" protocol
D
David Brownell 已提交
2800
 * @client: Handle to slave device
2801
 * @command: Byte interpreted by slave
D
David Brownell 已提交
2802 2803 2804
 * @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.
 *
2805 2806
 * 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
2807 2808 2809 2810 2811 2812
 *
 * 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.
 */
2813
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2814 2815 2816
			      u8 *values)
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2817
	int status;
2818

D
David Brownell 已提交
2819 2820 2821 2822 2823
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BLOCK_DATA, &data);
	if (status)
		return status;
2824 2825 2826 2827 2828 2829

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

2830 2831 2832 2833 2834 2835 2836 2837 2838 2839
/**
 * 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.
 */
2840
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2841
			       u8 length, const u8 *values)
L
Linus Torvalds 已提交
2842 2843
{
	union i2c_smbus_data data;
2844

L
Linus Torvalds 已提交
2845 2846 2847
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
2848
	memcpy(&data.block[1], values, length);
2849 2850 2851
	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
2852
}
D
David Brownell 已提交
2853
EXPORT_SYMBOL(i2c_smbus_write_block_data);
L
Linus Torvalds 已提交
2854 2855

/* Returns the number of read bytes */
2856
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2857
				  u8 length, u8 *values)
L
Linus Torvalds 已提交
2858 2859
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2860
	int status;
2861

2862 2863 2864
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
D
David Brownell 已提交
2865 2866 2867 2868 2869
	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;
2870 2871 2872

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
L
Linus Torvalds 已提交
2873
}
D
David Brownell 已提交
2874
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
L
Linus Torvalds 已提交
2875

2876
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2877
				   u8 length, const u8 *values)
2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888
{
	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
2889
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2890

D
David Brownell 已提交
2891
/* Simulate a SMBus command using the i2c protocol
L
Linus Torvalds 已提交
2892
   No checking of parameters is done!  */
2893 2894 2895 2896
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
2897 2898 2899 2900 2901
{
	/* 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. */
2902 2903
	unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
	unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2904
	int num = read_write == I2C_SMBUS_READ ? 2 : 1;
L
Linus Torvalds 已提交
2905
	int i;
2906
	u8 partial_pec = 0;
D
David Brownell 已提交
2907
	int status;
2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920
	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
2921 2922

	msgbuf0[0] = command;
2923
	switch (size) {
L
Linus Torvalds 已提交
2924 2925 2926
	case I2C_SMBUS_QUICK:
		msg[0].len = 0;
		/* Special case: The read/write field is used as data */
R
Roel Kluin 已提交
2927 2928
		msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
					I2C_M_RD : 0);
L
Linus Torvalds 已提交
2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949
		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 {
2950
			msg[0].len = 3;
L
Linus Torvalds 已提交
2951
			msgbuf0[1] = data->word & 0xff;
2952
			msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
2953 2954 2955 2956 2957 2958 2959 2960
		}
		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;
2961
		msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
2962 2963 2964
		break;
	case I2C_SMBUS_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
2965 2966 2967
			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
2968 2969 2970
		} else {
			msg[0].len = data->block[0] + 2;
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
D
David Brownell 已提交
2971 2972 2973 2974
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
2975
			}
2976
			for (i = 1; i < msg[0].len; i++)
L
Linus Torvalds 已提交
2977 2978 2979 2980
				msgbuf0[i] = data->block[i-1];
		}
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
2981 2982 2983
		num = 2; /* Another special case */
		read_write = I2C_SMBUS_READ;
		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
D
David Brownell 已提交
2984 2985
			dev_err(&adapter->dev,
				"Invalid block write size %d\n",
2986
				data->block[0]);
D
David Brownell 已提交
2987
			return -EINVAL;
2988 2989 2990 2991 2992 2993 2994 2995
		}
		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
2996 2997
	case I2C_SMBUS_I2C_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
2998
			msg[1].len = data->block[0];
L
Linus Torvalds 已提交
2999 3000
		} else {
			msg[0].len = data->block[0] + 1;
3001
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
D
David Brownell 已提交
3002 3003 3004 3005
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3006 3007 3008 3009 3010 3011
			}
			for (i = 1; i <= data->block[0]; i++)
				msgbuf0[i] = data->block[i];
		}
		break;
	default:
D
David Brownell 已提交
3012 3013
		dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
3014 3015
	}

3016 3017 3018 3019 3020
	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
3021
			if (num == 1) /* Write only */
3022 3023 3024 3025 3026 3027
				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
3028
			msg[num-1].len++;
3029 3030
	}

D
David Brownell 已提交
3031 3032 3033
	status = i2c_transfer(adapter, msg, num);
	if (status < 0)
		return status;
L
Linus Torvalds 已提交
3034

3035 3036
	/* Check PEC if last message is a read */
	if (i && (msg[num-1].flags & I2C_M_RD)) {
D
David Brownell 已提交
3037 3038 3039
		status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
		if (status < 0)
			return status;
3040 3041
	}

L
Linus Torvalds 已提交
3042
	if (read_write == I2C_SMBUS_READ)
3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062
		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
3063 3064 3065 3066
		}
	return 0;
}

3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079
/**
 * 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
3080
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3081
		   char read_write, u8 command, int protocol,
Z
Zhenwen Xu 已提交
3082
		   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
3083
{
3084 3085
	unsigned long orig_jiffies;
	int try;
L
Linus Torvalds 已提交
3086 3087
	s32 res;

3088 3089 3090 3091 3092 3093 3094 3095
	/* 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
3096
	flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
L
Linus Torvalds 已提交
3097 3098

	if (adapter->algo->smbus_xfer) {
3099
		i2c_lock_adapter(adapter);
3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112

		/* 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;
		}
3113
		i2c_unlock_adapter(adapter);
L
Linus Torvalds 已提交
3114

3115
		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3116
			goto trace;
3117 3118 3119 3120 3121 3122
		/*
		 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
		 * implement native support for the SMBus operation.
		 */
	}

3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133
	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
3134 3135 3136
}
EXPORT_SYMBOL(i2c_smbus_xfer);

3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193
/**
 * 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);

3194
#if IS_ENABLED(CONFIG_I2C_SLAVE)
W
Wolfram Sang 已提交
3195 3196 3197 3198
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
	int ret;

3199 3200
	if (!client || !slave_cb) {
		WARN(1, "insufficent data\n");
W
Wolfram Sang 已提交
3201
		return -EINVAL;
3202
	}
W
Wolfram Sang 已提交
3203

3204 3205 3206 3207
	if (!(client->flags & I2C_CLIENT_SLAVE))
		dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
			 __func__);

W
Wolfram Sang 已提交
3208 3209
	if (!(client->flags & I2C_CLIENT_TEN)) {
		/* Enforce stricter address checking */
3210
		ret = i2c_check_7bit_addr_validity_strict(client->addr);
3211 3212
		if (ret) {
			dev_err(&client->dev, "%s: invalid address\n", __func__);
W
Wolfram Sang 已提交
3213
			return ret;
3214
		}
W
Wolfram Sang 已提交
3215 3216
	}

3217 3218
	if (!client->adapter->algo->reg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
W
Wolfram Sang 已提交
3219
		return -EOPNOTSUPP;
3220
	}
W
Wolfram Sang 已提交
3221 3222 3223 3224 3225 3226 3227

	client->slave_cb = slave_cb;

	i2c_lock_adapter(client->adapter);
	ret = client->adapter->algo->reg_slave(client);
	i2c_unlock_adapter(client->adapter);

3228
	if (ret) {
W
Wolfram Sang 已提交
3229
		client->slave_cb = NULL;
3230 3231
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
	}
W
Wolfram Sang 已提交
3232 3233 3234 3235 3236 3237 3238 3239 3240

	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_register);

int i2c_slave_unregister(struct i2c_client *client)
{
	int ret;

3241 3242
	if (!client->adapter->algo->unreg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
W
Wolfram Sang 已提交
3243
		return -EOPNOTSUPP;
3244
	}
W
Wolfram Sang 已提交
3245 3246 3247 3248 3249 3250 3251

	i2c_lock_adapter(client->adapter);
	ret = client->adapter->algo->unreg_slave(client);
	i2c_unlock_adapter(client->adapter);

	if (ret == 0)
		client->slave_cb = NULL;
3252 3253
	else
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
W
Wolfram Sang 已提交
3254 3255 3256 3257

	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
3258
#endif
W
Wolfram Sang 已提交
3259

L
Linus Torvalds 已提交
3260 3261 3262
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");