i2c-core.c 87.2 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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static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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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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	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
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}

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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)
633
		bri->unprepare_recovery(adap);
634 635 636 637 638 639 640 641

	return ret;
}

int i2c_generic_scl_recovery(struct i2c_adapter *adap)
{
	return i2c_generic_recovery(adap);
}
642
EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
643 644 645 646 647 648 649 650 651 652 653 654 655 656

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;
}
657
EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
658 659 660 661 662 663 664 665 666

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);
}
667
EXPORT_SYMBOL_GPL(i2c_recover_bus);
668

669
static int i2c_device_probe(struct device *dev)
L
Linus Torvalds 已提交
670
{
671 672
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
673
	int status;
D
David Brownell 已提交
674

675 676 677
	if (!client)
		return 0;

678 679 680
	if (!client->irq) {
		int irq = -ENOENT;

681 682 683 684 685
		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)) {
686
			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
687
		}
688
		if (irq == -EPROBE_DEFER)
689
			return irq;
690 691
		if (irq < 0)
			irq = 0;
692 693 694 695

		client->irq = irq;
	}

696
	driver = to_i2c_driver(dev->driver);
J
Jean Delvare 已提交
697
	if (!driver->probe || !driver->id_table)
D
David Brownell 已提交
698
		return -ENODEV;
699

700 701 702 703 704 705 706 707 708 709 710 711 712 713
	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
714
			status = dev_pm_set_wake_irq(dev, client->irq);
715 716 717 718 719 720 721
		else
			status = 0;

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

D
David Brownell 已提交
722
	dev_dbg(dev, "probe\n");
723

724 725
	status = of_clk_set_defaults(dev->of_node, false);
	if (status < 0)
726
		goto err_clear_wakeup_irq;
727

728
	status = dev_pm_domain_attach(&client->dev, true);
729 730 731 732 733 734
	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;
735

736 737 738 739 740 741 742
	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);
743
	return status;
744
}
L
Linus Torvalds 已提交
745

746 747
static int i2c_device_remove(struct device *dev)
{
748
	struct i2c_client	*client = i2c_verify_client(dev);
D
David Brownell 已提交
749
	struct i2c_driver	*driver;
750
	int status = 0;
D
David Brownell 已提交
751

752
	if (!client || !dev->driver)
D
David Brownell 已提交
753 754 755 756 757 758 759
		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	}
760

761
	dev_pm_domain_detach(&client->dev, true);
762 763 764 765

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

D
David Brownell 已提交
766
	return status;
L
Linus Torvalds 已提交
767 768
}

769
static void i2c_device_shutdown(struct device *dev)
L
Linus Torvalds 已提交
770
{
771
	struct i2c_client *client = i2c_verify_client(dev);
772 773
	struct i2c_driver *driver;

774
	if (!client || !dev->driver)
775 776 777
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
778
		driver->shutdown(client);
L
Linus Torvalds 已提交
779 780
}

781 782 783 784 785
static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

Z
Zhenwen Xu 已提交
786
static ssize_t
787
show_name(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
788
{
789 790
	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
791
}
792
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
D
David Brownell 已提交
793

Z
Zhenwen Xu 已提交
794 795
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
796 797
{
	struct i2c_client *client = to_i2c_client(dev);
798 799 800 801 802 803
	int len;

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

804
	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
805
}
806 807 808 809
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
810
	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
811 812 813
	&dev_attr_modalias.attr,
	NULL
};
814
ATTRIBUTE_GROUPS(i2c_dev);
815

J
Jon Smirl 已提交
816
struct bus_type i2c_bus_type = {
817 818 819 820 821
	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
822
};
J
Jon Smirl 已提交
823
EXPORT_SYMBOL_GPL(i2c_bus_type);
824

825
static struct device_type i2c_client_type = {
826
	.groups		= i2c_dev_groups,
827 828 829 830
	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};

831 832 833 834 835 836 837 838 839 840 841 842

/**
 * 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)
{
843
	return (dev->type == &i2c_client_type)
844 845 846 847 848 849
			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


850 851 852 853 854 855 856 857 858 859 860 861 862 863 864
/* 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;
}

865
/* This is a permissive address validity check, I2C address map constraints
L
Lucas De Marchi 已提交
866
 * are purposely not enforced, except for the general call address. */
867
static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
868
{
869
	if (flags & I2C_CLIENT_TEN) {
870
		/* 10-bit address, all values are valid */
871
		if (addr > 0x3ff)
872 873 874
			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
875
		if (addr == 0x00 || addr > 0x7f)
876 877 878 879 880
			return -EINVAL;
	}
	return 0;
}

881 882 883 884
/* 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. */
885
static int i2c_check_7bit_addr_validity_strict(unsigned short addr)
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901
{
	/*
	 * 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;
}

902 903 904 905 906
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

907
	if (client && i2c_encode_flags_to_addr(client) == addr)
908 909 910 911
		return -EBUSY;
	return 0;
}

912 913 914
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
915
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
916 917 918 919 920
	int result;

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

921 922
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940

	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;
}

941 942
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
943
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
944 945
	int result = 0;

946 947
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
948 949 950 951 952 953

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

	return result;
954 955
}

956
/**
957
 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
958
 * @adapter: Target I2C bus segment
959 960
 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 *	locks only this branch in the adapter tree
961
 */
962 963
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
				 unsigned int flags)
964
{
965
	rt_mutex_lock(&adapter->bus_lock);
966 967 968
}

/**
969
 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
970
 * @adapter: Target I2C bus segment
971 972
 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	trylocks only this branch in the adapter tree
973
 */
974 975
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
976
{
977
	return rt_mutex_trylock(&adapter->bus_lock);
978 979 980
}

/**
981
 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
982
 * @adapter: Target I2C bus segment
983 984
 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	unlocks only this branch in the adapter tree
985
 */
986 987
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
988
{
989
	rt_mutex_unlock(&adapter->bus_lock);
990 991
}

992 993 994 995 996 997 998 999 1000 1001 1002
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),
1003
		     i2c_encode_flags_to_addr(client));
1004 1005
}

1006
/**
1007
 * i2c_new_device - instantiate an i2c device
1008 1009
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
1010
 * Context: can sleep
1011
 *
1012 1013 1014 1015 1016 1017
 * 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.
1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034
 *
 * 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;
1035

A
Anton Vorontsov 已提交
1036 1037 1038
	if (info->archdata)
		client->dev.archdata = *info->archdata;

M
Marc Pignat 已提交
1039
	client->flags = info->flags;
1040 1041 1042 1043 1044
	client->addr = info->addr;
	client->irq = info->irq;

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

1045
	status = i2c_check_addr_validity(client->addr, client->flags);
1046 1047 1048 1049 1050 1051
	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;
	}

1052
	/* Check for address business */
1053
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1054 1055 1056 1057 1058
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
1059
	client->dev.type = &i2c_client_type;
1060
	client->dev.of_node = info->of_node;
1061
	client->dev.fwnode = info->fwnode;
1062

1063
	i2c_dev_set_name(adap, client);
1064 1065 1066 1067 1068 1069 1070
	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));

1071
	return client;
1072 1073 1074 1075

out_err:
	dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
		"(%d)\n", client->name, client->addr, status);
1076
out_err_silent:
1077 1078
	kfree(client);
	return NULL;
1079 1080 1081 1082 1083 1084 1085
}
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
1086
 * Context: can sleep
1087 1088
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
1089
{
1090 1091
	if (client->dev.of_node)
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
D
David Brownell 已提交
1092 1093
	device_unregister(&client->dev);
}
1094
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
1095 1096


J
Jean Delvare 已提交
1097 1098 1099 1100 1101
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

1102 1103 1104 1105 1106 1107 1108
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
1109 1110 1111 1112 1113 1114
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
1115 1116
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
1117
	.id_table	= dummy_id,
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137
};

/**
 * 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
1138
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1139 1140
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
1141
		I2C_BOARD_INFO("dummy", address),
1142 1143 1144 1145 1146 1147
	};

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

1148 1149
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
1150 1151
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
1152
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
1153
{
1154
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
1155 1156 1157
	complete(&adap->dev_released);
}

1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173
/*
 * 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;
}

1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 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
/*
 * 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;
	}

1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
	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;
	}

1228 1229
	client = i2c_new_device(adap, &info);
	if (!client)
1230
		return -EINVAL;
1231 1232

	/* Keep track of the added device */
1233
	mutex_lock(&adap->userspace_clients_lock);
1234
	list_add_tail(&client->detected, &adap->userspace_clients);
1235
	mutex_unlock(&adap->userspace_clients_lock);
1236 1237 1238 1239 1240
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1241
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274

/*
 * 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;
1275 1276
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1277 1278
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1279
		if (i2c_encode_flags_to_addr(client) == addr) {
1280 1281 1282 1283 1284 1285 1286 1287 1288
			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;
		}
	}
1289
	mutex_unlock(&adap->userspace_clients_lock);
1290 1291 1292 1293 1294 1295

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1296 1297
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1298 1299 1300 1301 1302 1303 1304

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1305
ATTRIBUTE_GROUPS(i2c_adapter);
1306

1307
struct device_type i2c_adapter_type = {
1308
	.groups		= i2c_adapter_groups,
1309
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1310
};
1311
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1312

1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
/**
 * 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);

1330 1331 1332 1333
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1334 1335 1336 1337
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1338
	down_read(&__i2c_board_lock);
1339 1340 1341 1342
	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
1343 1344
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1345 1346
				devinfo->board_info.addr);
	}
1347
	up_read(&__i2c_board_lock);
1348 1349
}

1350 1351 1352
/* OF support code */

#if IS_ENABLED(CONFIG_OF)
1353 1354
static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
						 struct device_node *node)
1355
{
1356 1357 1358
	struct i2c_client *result;
	struct i2c_board_info info = {};
	struct dev_archdata dev_ad = {};
W
Wolfram Sang 已提交
1359 1360
	const __be32 *addr_be;
	u32 addr;
1361
	int len;
1362

1363
	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1364

1365 1366 1367 1368 1369
	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);
	}
1370

W
Wolfram Sang 已提交
1371 1372
	addr_be = of_get_property(node, "reg", &len);
	if (!addr_be || (len < sizeof(*addr_be))) {
1373 1374 1375 1376
		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1377

W
Wolfram Sang 已提交
1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389
	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)) {
1390 1391 1392 1393
		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
			info.addr, node->full_name);
		return ERR_PTR(-EINVAL);
	}
1394

W
Wolfram Sang 已提交
1395
	info.addr = addr;
1396 1397
	info.of_node = of_node_get(node);
	info.archdata = &dev_ad;
1398

1399 1400
	if (of_get_property(node, "wakeup-source", NULL))
		info.flags |= I2C_CLIENT_WAKE;
1401

1402 1403 1404 1405 1406 1407 1408 1409 1410
	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;
}
1411

1412 1413 1414
static void of_i2c_register_devices(struct i2c_adapter *adap)
{
	struct device_node *node;
1415

1416 1417 1418
	/* Only register child devices if the adapter has a node pointer set */
	if (!adap->dev.of_node)
		return;
1419

1420 1421
	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");

1422 1423 1424
	for_each_available_child_of_node(adap->dev.of_node, node) {
		if (of_node_test_and_set_flag(node, OF_POPULATED))
			continue;
1425
		of_i2c_register_device(adap, node);
1426
	}
1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437
}

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;
1438
	struct i2c_client *client;
1439

1440
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1441 1442 1443
	if (!dev)
		return NULL;

1444 1445 1446 1447 1448
	client = i2c_verify_client(dev);
	if (!client)
		put_device(dev);

	return client;
1449 1450 1451 1452 1453 1454 1455
}
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;
1456
	struct i2c_adapter *adapter;
1457

1458
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1459 1460 1461
	if (!dev)
		return NULL;

1462 1463 1464 1465 1466
	adapter = i2c_verify_adapter(dev);
	if (!adapter)
		put_device(dev);

	return adapter;
1467 1468
}
EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486

/* 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);
1487 1488 1489 1490
#else
static void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif /* CONFIG_OF */

J
Jean Delvare 已提交
1491 1492
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1493
{
1494 1495 1496 1497
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

	/* Let legacy drivers scan this bus for matching devices */
1498
	if (driver->attach_adapter) {
J
Jean Delvare 已提交
1499 1500
		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
			 driver->driver.name);
1501 1502
		dev_warn(&adap->dev, "Please use another way to instantiate "
			 "your i2c_client\n");
1503 1504 1505 1506 1507 1508
		/* We ignore the return code; if it fails, too bad */
		driver->attach_adapter(adap);
	}
	return 0;
}

J
Jean Delvare 已提交
1509 1510 1511 1512 1513
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1514
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1515
{
J
Jean Delvare 已提交
1516
	int res = 0;
L
Linus Torvalds 已提交
1517

1518
	/* Can't register until after driver model init */
1519
	if (WARN_ON(!is_registered)) {
1520 1521 1522
		res = -EAGAIN;
		goto out_list;
	}
1523

1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535
	/* 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;
	}

1536 1537 1538 1539 1540 1541
	if (!adap->lock_bus) {
		adap->lock_bus = i2c_adapter_lock_bus;
		adap->trylock_bus = i2c_adapter_trylock_bus;
		adap->unlock_bus = i2c_adapter_unlock_bus;
	}

1542
	rt_mutex_init(&adap->bus_lock);
1543
	mutex_init(&adap->userspace_clients_lock);
1544
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
1545

1546 1547 1548 1549
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

1550
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1551 1552
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
1553 1554 1555
	res = device_register(&adap->dev);
	if (res)
		goto out_list;
L
Linus Torvalds 已提交
1556

1557 1558
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

1559
	pm_runtime_no_callbacks(&adap->dev);
1560
	pm_suspend_ignore_children(&adap->dev, true);
1561
	pm_runtime_enable(&adap->dev);
1562

1563 1564 1565 1566 1567 1568 1569 1570
#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

1571 1572 1573 1574 1575 1576 1577 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
	/* 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:
1604
	/* create pre-declared device nodes */
1605
	of_i2c_register_devices(adap);
1606
	acpi_i2c_register_devices(adap);
1607
	acpi_i2c_install_space_handler(adap);
1608

1609 1610 1611
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

1612
	/* Notify drivers */
1613
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
1614
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
1615
	mutex_unlock(&core_lock);
1616 1617

	return 0;
1618 1619

out_list:
1620
	mutex_lock(&core_lock);
1621
	idr_remove(&i2c_adapter_idr, adap->nr);
1622 1623
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
1624 1625
}

1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646
/**
 * __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);
}

1647 1648 1649
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
1650
 * Context: can sleep
1651 1652
 *
 * This routine is used to declare an I2C adapter when its bus number
1653 1654 1655
 * 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.
1656 1657 1658 1659 1660 1661 1662
 *
 * 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)
{
1663
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
1664
	int id;
1665

1666 1667 1668 1669 1670 1671 1672 1673
	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
1674
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
1675 1676
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
1677
	mutex_unlock(&core_lock);
T
Tejun Heo 已提交
1678 1679
	if (id < 0)
		return id;
1680 1681

	adapter->nr = id;
T
Tejun Heo 已提交
1682

1683 1684 1685 1686 1687 1688 1689
	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
1690
 * Context: can sleep
1691 1692
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
1693 1694
 * 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
1695 1696
 * is used to properly configure I2C devices.
 *
1697 1698 1699
 * 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.
 *
1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711
 * 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)
{
1712 1713
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
1714

1715
	return __i2c_add_numbered_adapter(adap);
1716 1717 1718
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
1719
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
1720
			      struct i2c_adapter *adapter)
1721
{
1722
	struct i2c_client *client, *_n;
1723

1724 1725
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
1726 1727 1728 1729 1730 1731 1732 1733
	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);
		}
	}
1734 1735
}

1736
static int __unregister_client(struct device *dev, void *dummy)
1737 1738 1739 1740 1741 1742 1743 1744
{
	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)
1745 1746 1747 1748 1749 1750 1751
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client)
		i2c_unregister_device(client);
	return 0;
}

J
Jean Delvare 已提交
1752 1753
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
1754 1755
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
1756 1757
}

D
David Brownell 已提交
1758 1759 1760 1761 1762 1763 1764 1765
/**
 * 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.
 */
1766
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1767
{
1768
	struct i2c_adapter *found;
1769
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
1770 1771

	/* First make sure that this adapter was ever added */
1772 1773 1774 1775
	mutex_lock(&core_lock);
	found = idr_find(&i2c_adapter_idr, adap->nr);
	mutex_unlock(&core_lock);
	if (found != adap) {
1776 1777
		pr_debug("i2c-core: attempting to delete unregistered "
			 "adapter [%s]\n", adap->name);
1778
		return;
L
Linus Torvalds 已提交
1779 1780
	}

1781
	acpi_i2c_remove_space_handler(adap);
1782
	/* Tell drivers about this removal */
1783
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
1784
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
1785
			       __process_removed_adapter);
1786
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1787

1788
	/* Remove devices instantiated from sysfs */
1789 1790
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1791 1792 1793 1794 1795 1796
	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);
1797
	}
1798
	mutex_unlock(&adap->userspace_clients_lock);
1799

1800
	/* Detach any active clients. This can't fail, thus we do not
1801 1802 1803 1804
	 * 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
1805 1806
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
1807

1808 1809 1810 1811 1812
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

1813 1814 1815
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

1816 1817
	pm_runtime_disable(&adap->dev);

1818 1819 1820 1821 1822
	/* 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
1823
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1824
	 */
L
Linus Torvalds 已提交
1825 1826 1827 1828
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

1829
	/* free bus id */
1830
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
1831
	idr_remove(&i2c_adapter_idr, adap->nr);
1832
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1833

1834 1835 1836
	/* 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
1837
}
D
David Brownell 已提交
1838
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
1839

1840 1841 1842 1843 1844 1845 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
/**
 * 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
1892 1893
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905
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
1906
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
1907
{
1908 1909
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
1910
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
1911 1912
}

D
David Brownell 已提交
1913 1914
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1915
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
1916 1917
 */

1918
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
1919
{
1920
	int res;
L
Linus Torvalds 已提交
1921

1922
	/* Can't register until after driver model init */
1923
	if (WARN_ON(!is_registered))
1924 1925
		return -EAGAIN;

L
Linus Torvalds 已提交
1926
	/* add the driver to the list of i2c drivers in the driver core */
1927
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
1928 1929
	driver->driver.bus = &i2c_bus_type;

1930
	/* When registration returns, the driver core
1931 1932
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
1933 1934
	res = driver_register(&driver->driver);
	if (res)
1935
		return res;
D
David Brownell 已提交
1936

1937
	pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
1938

1939 1940
	INIT_LIST_HEAD(&driver->clients);
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
1941
	i2c_for_each_dev(driver, __process_new_driver);
1942

D
Dave Young 已提交
1943 1944 1945 1946
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
1947
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
1948
{
L
Lars-Peter Clausen 已提交
1949 1950 1951
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
1952 1953
}

D
David Brownell 已提交
1954 1955 1956
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
1957
 * Context: can sleep
D
David Brownell 已提交
1958
 */
1959
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
1960
{
J
Jean Delvare 已提交
1961
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
1962 1963

	driver_unregister(&driver->driver);
1964
	pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
1965
}
D
David Brownell 已提交
1966
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
1967

D
David Brownell 已提交
1968 1969
/* ------------------------------------------------------------------------- */

1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981
/**
 * 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
1982
{
1983 1984 1985
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
1986
}
D
David Brownell 已提交
1987
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
1988

1989 1990 1991 1992 1993 1994 1995
/**
 * 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
1996
{
1997 1998
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
1999
}
D
David Brownell 已提交
2000
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
2001

2002 2003 2004 2005 2006 2007 2008 2009 2010
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;
2011 2012 2013 2014
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
2015

2016 2017 2018
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
2019 2020 2021
	return 0;
}

L
Linus Torvalds 已提交
2022 2023
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
2024
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
2025

2026 2027 2028
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
2029
}
D
David Brownell 已提交
2030
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
2031

2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
#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 */

2046 2047 2048 2049 2050
		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
			put_device(&adap->dev);
			return NOTIFY_OK;
		}

2051 2052 2053 2054 2055 2056 2057 2058 2059 2060
		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:
2061 2062 2063 2064
		/* already depopulated? */
		if (!of_node_check_flag(rd->dn, OF_POPULATED))
			return NOTIFY_OK;

2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086
		/* 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
2087 2088 2089 2090
static int __init i2c_init(void)
{
	int retval;

2091 2092 2093 2094 2095 2096 2097
	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
2098 2099 2100
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
2101 2102 2103

	is_registered = true;

2104 2105 2106 2107 2108 2109 2110
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
2111 2112
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
2113
		goto class_err;
2114 2115 2116 2117

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

2118 2119
	return 0;

2120 2121 2122
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
2123
bus_err:
2124
#endif
2125
	is_registered = false;
2126 2127
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
2128 2129 2130 2131
}

static void __exit i2c_exit(void)
{
2132 2133
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2134
	i2c_del_driver(&dummy_driver);
2135 2136 2137
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
2138
	bus_unregister(&i2c_bus_type);
2139
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
2140 2141
}

D
David Brownell 已提交
2142 2143 2144 2145
/* 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
2146 2147 2148 2149 2150 2151 2152
module_exit(i2c_exit);

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

W
Wolfram Sang 已提交
2153 2154 2155 2156 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
/* 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;
}

2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228
/**
 * __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
2229 2230 2231
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244
	/* 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);
	}

2245 2246 2247 2248 2249 2250 2251 2252 2253 2254
	/* 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;
	}

2255 2256 2257 2258 2259 2260 2261 2262
	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);
	}

2263 2264 2265 2266
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278
/**
 * 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
2279
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
2280
{
2281
	int ret;
L
Linus Torvalds 已提交
2282

2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299
	/* 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
2300 2301 2302 2303
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
			dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
2304 2305 2306
				"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
2307 2308 2309
		}
#endif

2310
		if (in_atomic() || irqs_disabled()) {
2311
			ret = adap->trylock_bus(adap, I2C_LOCK_SEGMENT);
2312 2313 2314 2315
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
2316
			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
2317 2318
		}

2319
		ret = __i2c_transfer(adap, msgs, num);
2320
		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
2321 2322 2323 2324

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
2325
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
2326 2327
	}
}
D
David Brownell 已提交
2328
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
2329

2330 2331 2332 2333
/**
 * 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
2334
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2335 2336 2337
 *
 * Returns negative errno, or else the number of bytes written.
 */
2338
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
L
Linus Torvalds 已提交
2339 2340
{
	int ret;
2341
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2342 2343
	struct i2c_msg msg;

2344 2345 2346 2347
	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = (char *)buf;
D
David Brownell 已提交
2348

2349
	ret = i2c_transfer(adap, &msg, 1);
L
Linus Torvalds 已提交
2350

2351 2352 2353 2354
	/*
	 * If everything went ok (i.e. 1 msg transmitted), return #bytes
	 * transmitted, else error code.
	 */
2355
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2356
}
D
David Brownell 已提交
2357
EXPORT_SYMBOL(i2c_master_send);
L
Linus Torvalds 已提交
2358

2359 2360 2361 2362
/**
 * 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
2363
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2364 2365 2366
 *
 * Returns negative errno, or else the number of bytes read.
 */
2367
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
L
Linus Torvalds 已提交
2368
{
2369
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2370 2371
	struct i2c_msg msg;
	int ret;
2372 2373 2374 2375 2376 2377 2378 2379 2380

	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);

2381 2382 2383 2384
	/*
	 * If everything went ok (i.e. 1 msg received), return #bytes received,
	 * else error code.
	 */
2385
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2386
}
D
David Brownell 已提交
2387
EXPORT_SYMBOL(i2c_master_recv);
L
Linus Torvalds 已提交
2388 2389 2390 2391 2392 2393 2394

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

2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418
/*
 * 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
2419 2420
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2421 2422
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2423 2424 2425 2426
	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 {
2427 2428
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2429 2430
		err = -EOPNOTSUPP;
	}
2431 2432 2433 2434

	return err >= 0;
}

J
Jean Delvare 已提交
2435
static int i2c_detect_address(struct i2c_client *temp_client,
2436 2437 2438 2439 2440 2441 2442 2443
			      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 */
2444
	err = i2c_check_7bit_addr_validity_strict(addr);
2445
	if (err) {
2446 2447
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2448
		return err;
2449 2450
	}

2451
	/* Skip if already in use (7 bit, no need to encode flags) */
2452
	if (i2c_check_addr_busy(adapter, addr))
2453 2454
		return 0;

J
Jean Delvare 已提交
2455
	/* Make sure there is something at this address */
2456 2457
	if (!i2c_default_probe(adapter, addr))
		return 0;
2458 2459 2460 2461

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
2462
	err = driver->detect(temp_client, &info);
2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477
	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 */
2478 2479 2480 2481 2482 2483 2484
		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);

2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498
		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)
{
2499
	const unsigned short *address_list;
2500 2501 2502 2503
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

2504 2505
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
2506 2507
		return 0;

2508 2509 2510 2511 2512 2513 2514 2515 2516 2517
	/* 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
2518 2519 2520 2521
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

2522 2523 2524 2525 2526 2527
	/* 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;

2528
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2529
		dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2530 2531
			"addr 0x%02x\n", adap_id, address_list[i]);
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
2532
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
2533 2534
		if (unlikely(err))
			break;
2535 2536 2537 2538 2539 2540
	}

	kfree(temp_client);
	return err;
}

2541 2542 2543 2544 2545 2546 2547
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
2548 2549 2550
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
2551 2552
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
2553 2554 2555
{
	int i;

2556
	if (!probe)
2557
		probe = i2c_default_probe;
J
Jean Delvare 已提交
2558 2559 2560

	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
2561
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
J
Jean Delvare 已提交
2562 2563 2564 2565 2566
			dev_warn(&adap->dev, "Invalid 7-bit address "
				 "0x%02x\n", addr_list[i]);
			continue;
		}

2567
		/* Check address availability (7 bit, no need to encode flags) */
2568
		if (i2c_check_addr_busy(adap, addr_list[i])) {
J
Jean Delvare 已提交
2569 2570 2571 2572 2573
			dev_dbg(&adap->dev, "Address 0x%02x already in "
				"use, not probing\n", addr_list[i]);
			continue;
		}

2574
		/* Test address responsiveness */
2575
		if (probe(adap, addr_list[i]))
2576
			break;
J
Jean Delvare 已提交
2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588
	}

	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);

2589
struct i2c_adapter *i2c_get_adapter(int nr)
L
Linus Torvalds 已提交
2590 2591
{
	struct i2c_adapter *adapter;
D
David Brownell 已提交
2592

J
Jean Delvare 已提交
2593
	mutex_lock(&core_lock);
2594
	adapter = idr_find(&i2c_adapter_idr, nr);
2595 2596 2597 2598 2599 2600
	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
2601 2602
		adapter = NULL;

2603
 exit:
J
Jean Delvare 已提交
2604
	mutex_unlock(&core_lock);
2605
	return adapter;
L
Linus Torvalds 已提交
2606
}
D
David Brownell 已提交
2607
EXPORT_SYMBOL(i2c_get_adapter);
L
Linus Torvalds 已提交
2608 2609 2610

void i2c_put_adapter(struct i2c_adapter *adap)
{
2611 2612 2613 2614 2615
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
L
Linus Torvalds 已提交
2616
}
D
David Brownell 已提交
2617
EXPORT_SYMBOL(i2c_put_adapter);
L
Linus Torvalds 已提交
2618 2619 2620

/* The SMBus parts */

D
David Brownell 已提交
2621
#define POLY    (0x1070U << 3)
Z
Zhenwen Xu 已提交
2622
static u8 crc8(u16 data)
L
Linus Torvalds 已提交
2623 2624
{
	int i;
D
David Brownell 已提交
2625

2626
	for (i = 0; i < 8; i++) {
D
David Brownell 已提交
2627
		if (data & 0x8000)
L
Linus Torvalds 已提交
2628 2629 2630 2631 2632 2633
			data = data ^ POLY;
		data = data << 1;
	}
	return (u8)(data >> 8);
}

2634 2635
/* 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
2636 2637 2638
{
	int i;

2639
	for (i = 0; i < count; i++)
2640
		crc = crc8((crc ^ p[i]) << 8);
L
Linus Torvalds 已提交
2641 2642 2643
	return crc;
}

2644 2645
/* 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
2646
{
2647
	/* The address will be sent first */
2648
	u8 addr = i2c_8bit_addr_from_msg(msg);
2649 2650 2651 2652
	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
2653 2654
}

2655 2656
/* Used for write only transactions */
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
L
Linus Torvalds 已提交
2657
{
2658 2659
	msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
	msg->len++;
L
Linus Torvalds 已提交
2660 2661
}

2662 2663 2664 2665 2666 2667
/* 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
2668
{
2669 2670
	u8 rpec = msg->buf[--msg->len];
	cpec = i2c_smbus_msg_pec(cpec, msg);
L
Linus Torvalds 已提交
2671 2672 2673 2674

	if (rpec != cpec) {
		pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
			rpec, cpec);
D
David Brownell 已提交
2675
		return -EBADMSG;
L
Linus Torvalds 已提交
2676
	}
D
David Brownell 已提交
2677
	return 0;
L
Linus Torvalds 已提交
2678 2679
}

2680 2681 2682 2683 2684 2685 2686
/**
 * 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.
 */
2687
s32 i2c_smbus_read_byte(const struct i2c_client *client)
L
Linus Torvalds 已提交
2688 2689
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2690 2691 2692 2693 2694 2695
	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
2696
}
D
David Brownell 已提交
2697
EXPORT_SYMBOL(i2c_smbus_read_byte);
L
Linus Torvalds 已提交
2698

2699 2700 2701 2702 2703 2704 2705 2706
/**
 * 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.
 */
2707
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
L
Linus Torvalds 已提交
2708
{
2709
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2710
	                      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
L
Linus Torvalds 已提交
2711
}
D
David Brownell 已提交
2712
EXPORT_SYMBOL(i2c_smbus_write_byte);
L
Linus Torvalds 已提交
2713

2714 2715 2716 2717 2718 2719 2720 2721
/**
 * 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.
 */
2722
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2723 2724
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2725 2726 2727 2728 2729 2730
	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
2731
}
D
David Brownell 已提交
2732
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
L
Linus Torvalds 已提交
2733

2734 2735 2736 2737 2738 2739 2740 2741 2742
/**
 * 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.
 */
2743 2744
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
			      u8 value)
L
Linus Torvalds 已提交
2745 2746 2747
{
	union i2c_smbus_data data;
	data.byte = value;
2748 2749 2750
	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
2751
}
D
David Brownell 已提交
2752
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
L
Linus Torvalds 已提交
2753

2754 2755 2756 2757 2758 2759 2760 2761
/**
 * 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.
 */
2762
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2763 2764
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2765 2766 2767 2768 2769 2770
	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
2771
}
D
David Brownell 已提交
2772
EXPORT_SYMBOL(i2c_smbus_read_word_data);
L
Linus Torvalds 已提交
2773

2774 2775 2776 2777 2778 2779 2780 2781 2782
/**
 * 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.
 */
2783 2784
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
			      u16 value)
L
Linus Torvalds 已提交
2785 2786 2787
{
	union i2c_smbus_data data;
	data.word = value;
2788 2789 2790
	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
2791
}
D
David Brownell 已提交
2792
EXPORT_SYMBOL(i2c_smbus_write_word_data);
L
Linus Torvalds 已提交
2793

D
David Brownell 已提交
2794
/**
2795
 * i2c_smbus_read_block_data - SMBus "block read" protocol
D
David Brownell 已提交
2796
 * @client: Handle to slave device
2797
 * @command: Byte interpreted by slave
D
David Brownell 已提交
2798 2799 2800
 * @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.
 *
2801 2802
 * 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
2803 2804 2805 2806 2807 2808
 *
 * 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.
 */
2809
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2810 2811 2812
			      u8 *values)
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2813
	int status;
2814

D
David Brownell 已提交
2815 2816 2817 2818 2819
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BLOCK_DATA, &data);
	if (status)
		return status;
2820 2821 2822 2823 2824 2825

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

2826 2827 2828 2829 2830 2831 2832 2833 2834 2835
/**
 * 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.
 */
2836
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2837
			       u8 length, const u8 *values)
L
Linus Torvalds 已提交
2838 2839
{
	union i2c_smbus_data data;
2840

L
Linus Torvalds 已提交
2841 2842 2843
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
2844
	memcpy(&data.block[1], values, length);
2845 2846 2847
	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
2848
}
D
David Brownell 已提交
2849
EXPORT_SYMBOL(i2c_smbus_write_block_data);
L
Linus Torvalds 已提交
2850 2851

/* Returns the number of read bytes */
2852
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2853
				  u8 length, u8 *values)
L
Linus Torvalds 已提交
2854 2855
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2856
	int status;
2857

2858 2859 2860
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
D
David Brownell 已提交
2861 2862 2863 2864 2865
	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;
2866 2867 2868

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
L
Linus Torvalds 已提交
2869
}
D
David Brownell 已提交
2870
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
L
Linus Torvalds 已提交
2871

2872
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2873
				   u8 length, const u8 *values)
2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884
{
	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
2885
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2886

D
David Brownell 已提交
2887
/* Simulate a SMBus command using the i2c protocol
L
Linus Torvalds 已提交
2888
   No checking of parameters is done!  */
2889 2890 2891 2892
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
2893 2894 2895 2896 2897
{
	/* 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. */
2898 2899
	unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
	unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2900
	int num = read_write == I2C_SMBUS_READ ? 2 : 1;
L
Linus Torvalds 已提交
2901
	int i;
2902
	u8 partial_pec = 0;
D
David Brownell 已提交
2903
	int status;
2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916
	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
2917 2918

	msgbuf0[0] = command;
2919
	switch (size) {
L
Linus Torvalds 已提交
2920 2921 2922
	case I2C_SMBUS_QUICK:
		msg[0].len = 0;
		/* Special case: The read/write field is used as data */
R
Roel Kluin 已提交
2923 2924
		msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
					I2C_M_RD : 0);
L
Linus Torvalds 已提交
2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945
		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 {
2946
			msg[0].len = 3;
L
Linus Torvalds 已提交
2947
			msgbuf0[1] = data->word & 0xff;
2948
			msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
2949 2950 2951 2952 2953 2954 2955 2956
		}
		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;
2957
		msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
2958 2959 2960
		break;
	case I2C_SMBUS_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
2961 2962 2963
			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
2964 2965 2966
		} else {
			msg[0].len = data->block[0] + 2;
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
D
David Brownell 已提交
2967 2968 2969 2970
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
2971
			}
2972
			for (i = 1; i < msg[0].len; i++)
L
Linus Torvalds 已提交
2973 2974 2975 2976
				msgbuf0[i] = data->block[i-1];
		}
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
2977 2978 2979
		num = 2; /* Another special case */
		read_write = I2C_SMBUS_READ;
		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
D
David Brownell 已提交
2980 2981
			dev_err(&adapter->dev,
				"Invalid block write size %d\n",
2982
				data->block[0]);
D
David Brownell 已提交
2983
			return -EINVAL;
2984 2985 2986 2987 2988 2989 2990 2991
		}
		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
2992 2993
	case I2C_SMBUS_I2C_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
2994
			msg[1].len = data->block[0];
L
Linus Torvalds 已提交
2995 2996
		} else {
			msg[0].len = data->block[0] + 1;
2997
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
D
David Brownell 已提交
2998 2999 3000 3001
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3002 3003 3004 3005 3006 3007
			}
			for (i = 1; i <= data->block[0]; i++)
				msgbuf0[i] = data->block[i];
		}
		break;
	default:
D
David Brownell 已提交
3008 3009
		dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
3010 3011
	}

3012 3013 3014 3015 3016
	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
3017
			if (num == 1) /* Write only */
3018 3019 3020 3021 3022 3023
				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
3024
			msg[num-1].len++;
3025 3026
	}

D
David Brownell 已提交
3027 3028 3029
	status = i2c_transfer(adapter, msg, num);
	if (status < 0)
		return status;
L
Linus Torvalds 已提交
3030

3031 3032
	/* Check PEC if last message is a read */
	if (i && (msg[num-1].flags & I2C_M_RD)) {
D
David Brownell 已提交
3033 3034 3035
		status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
		if (status < 0)
			return status;
3036 3037
	}

L
Linus Torvalds 已提交
3038
	if (read_write == I2C_SMBUS_READ)
3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058
		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
3059 3060 3061 3062
		}
	return 0;
}

3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075
/**
 * 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
3076
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3077
		   char read_write, u8 command, int protocol,
Z
Zhenwen Xu 已提交
3078
		   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
3079
{
3080 3081
	unsigned long orig_jiffies;
	int try;
L
Linus Torvalds 已提交
3082 3083
	s32 res;

3084 3085 3086 3087 3088 3089 3090 3091
	/* 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
3092
	flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
L
Linus Torvalds 已提交
3093 3094

	if (adapter->algo->smbus_xfer) {
3095
		i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108

		/* 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;
		}
3109
		i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
3110

3111
		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3112
			goto trace;
3113 3114 3115 3116 3117 3118
		/*
		 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
		 * implement native support for the SMBus operation.
		 */
	}

3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129
	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
3130 3131 3132
}
EXPORT_SYMBOL(i2c_smbus_xfer);

3133 3134 3135 3136 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
/**
 * 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);

3190
#if IS_ENABLED(CONFIG_I2C_SLAVE)
W
Wolfram Sang 已提交
3191 3192 3193 3194
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
	int ret;

3195 3196
	if (!client || !slave_cb) {
		WARN(1, "insufficent data\n");
W
Wolfram Sang 已提交
3197
		return -EINVAL;
3198
	}
W
Wolfram Sang 已提交
3199

3200 3201 3202 3203
	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
3204 3205
	if (!(client->flags & I2C_CLIENT_TEN)) {
		/* Enforce stricter address checking */
3206
		ret = i2c_check_7bit_addr_validity_strict(client->addr);
3207 3208
		if (ret) {
			dev_err(&client->dev, "%s: invalid address\n", __func__);
W
Wolfram Sang 已提交
3209
			return ret;
3210
		}
W
Wolfram Sang 已提交
3211 3212
	}

3213 3214
	if (!client->adapter->algo->reg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
W
Wolfram Sang 已提交
3215
		return -EOPNOTSUPP;
3216
	}
W
Wolfram Sang 已提交
3217 3218 3219 3220 3221 3222 3223

	client->slave_cb = slave_cb;

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

3224
	if (ret) {
W
Wolfram Sang 已提交
3225
		client->slave_cb = NULL;
3226 3227
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
	}
W
Wolfram Sang 已提交
3228 3229 3230 3231 3232 3233 3234 3235 3236

	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_register);

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

3237 3238
	if (!client->adapter->algo->unreg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
W
Wolfram Sang 已提交
3239
		return -EOPNOTSUPP;
3240
	}
W
Wolfram Sang 已提交
3241 3242 3243 3244 3245 3246 3247

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

	if (ret == 0)
		client->slave_cb = NULL;
3248 3249
	else
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
W
Wolfram Sang 已提交
3250 3251 3252 3253

	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
3254
#endif
W
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MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");