i2c-core.c 88.7 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

669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709
static void i2c_init_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	char *err_str;

	if (!bri)
		return;

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

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

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

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

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

710
static int i2c_device_probe(struct device *dev)
L
Linus Torvalds 已提交
711
{
712 713
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
714
	int status;
D
David Brownell 已提交
715

716 717 718
	if (!client)
		return 0;

719 720 721
	if (!client->irq) {
		int irq = -ENOENT;

722 723 724 725 726
		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)) {
727
			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
728
		}
729
		if (irq == -EPROBE_DEFER)
730
			return irq;
731 732
		if (irq < 0)
			irq = 0;
733 734 735 736

		client->irq = irq;
	}

737
	driver = to_i2c_driver(dev->driver);
J
Jean Delvare 已提交
738
	if (!driver->probe || !driver->id_table)
D
David Brownell 已提交
739
		return -ENODEV;
740

741 742 743 744 745 746 747 748 749 750 751 752 753 754
	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
755
			status = dev_pm_set_wake_irq(dev, client->irq);
756 757 758 759 760 761 762
		else
			status = 0;

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

D
David Brownell 已提交
763
	dev_dbg(dev, "probe\n");
764

765 766
	status = of_clk_set_defaults(dev->of_node, false);
	if (status < 0)
767
		goto err_clear_wakeup_irq;
768

769
	status = dev_pm_domain_attach(&client->dev, true);
770 771 772 773 774 775
	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;
776

777 778 779 780 781 782 783
	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);
784
	return status;
785
}
L
Linus Torvalds 已提交
786

787 788
static int i2c_device_remove(struct device *dev)
{
789
	struct i2c_client	*client = i2c_verify_client(dev);
D
David Brownell 已提交
790
	struct i2c_driver	*driver;
791
	int status = 0;
D
David Brownell 已提交
792

793
	if (!client || !dev->driver)
D
David Brownell 已提交
794 795 796 797 798 799 800
		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	}
801

802
	dev_pm_domain_detach(&client->dev, true);
803 804 805 806

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

D
David Brownell 已提交
807
	return status;
L
Linus Torvalds 已提交
808 809
}

810
static void i2c_device_shutdown(struct device *dev)
L
Linus Torvalds 已提交
811
{
812
	struct i2c_client *client = i2c_verify_client(dev);
813 814
	struct i2c_driver *driver;

815
	if (!client || !dev->driver)
816 817 818
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
819
		driver->shutdown(client);
L
Linus Torvalds 已提交
820 821
}

822 823 824 825 826
static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

Z
Zhenwen Xu 已提交
827
static ssize_t
828
show_name(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
829
{
830 831
	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
832
}
833
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
D
David Brownell 已提交
834

Z
Zhenwen Xu 已提交
835 836
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
837 838
{
	struct i2c_client *client = to_i2c_client(dev);
839 840 841 842 843 844
	int len;

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

845
	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
846
}
847 848 849 850
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
851
	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
852 853 854
	&dev_attr_modalias.attr,
	NULL
};
855
ATTRIBUTE_GROUPS(i2c_dev);
856

J
Jon Smirl 已提交
857
struct bus_type i2c_bus_type = {
858 859 860 861 862
	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
863
};
J
Jon Smirl 已提交
864
EXPORT_SYMBOL_GPL(i2c_bus_type);
865

866
static struct device_type i2c_client_type = {
867
	.groups		= i2c_dev_groups,
868 869 870 871
	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};

872 873 874 875 876 877 878 879 880 881 882 883

/**
 * 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)
{
884
	return (dev->type == &i2c_client_type)
885 886 887 888 889 890
			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
/* 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;
}

906
/* This is a permissive address validity check, I2C address map constraints
L
Lucas De Marchi 已提交
907
 * are purposely not enforced, except for the general call address. */
908
static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
909
{
910
	if (flags & I2C_CLIENT_TEN) {
911
		/* 10-bit address, all values are valid */
912
		if (addr > 0x3ff)
913 914 915
			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
916
		if (addr == 0x00 || addr > 0x7f)
917 918 919 920 921
			return -EINVAL;
	}
	return 0;
}

922 923 924 925
/* 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. */
926
static int i2c_check_7bit_addr_validity_strict(unsigned short addr)
927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942
{
	/*
	 * 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;
}

943 944 945 946 947
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

948
	if (client && i2c_encode_flags_to_addr(client) == addr)
949 950 951 952
		return -EBUSY;
	return 0;
}

953 954 955
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
956
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
957 958 959 960 961
	int result;

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

962 963
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981

	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;
}

982 983
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
984
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
985 986
	int result = 0;

987 988
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
989 990 991 992 993 994

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

	return result;
995 996
}

997
/**
998
 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
999
 * @adapter: Target I2C bus segment
1000 1001
 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 *	locks only this branch in the adapter tree
1002
 */
1003 1004
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
				 unsigned int flags)
1005
{
1006
	rt_mutex_lock(&adapter->bus_lock);
1007 1008 1009
}

/**
1010
 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
1011
 * @adapter: Target I2C bus segment
1012 1013
 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	trylocks only this branch in the adapter tree
1014
 */
1015 1016
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
1017
{
1018
	return rt_mutex_trylock(&adapter->bus_lock);
1019 1020 1021
}

/**
1022
 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
1023
 * @adapter: Target I2C bus segment
1024 1025
 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	unlocks only this branch in the adapter tree
1026
 */
1027 1028
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
1029
{
1030
	rt_mutex_unlock(&adapter->bus_lock);
1031 1032
}

1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043
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),
1044
		     i2c_encode_flags_to_addr(client));
1045 1046
}

1047
/**
1048
 * i2c_new_device - instantiate an i2c device
1049 1050
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
1051
 * Context: can sleep
1052
 *
1053 1054 1055 1056 1057 1058
 * 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.
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
 *
 * 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;
1076

A
Anton Vorontsov 已提交
1077 1078 1079
	if (info->archdata)
		client->dev.archdata = *info->archdata;

M
Marc Pignat 已提交
1080
	client->flags = info->flags;
1081 1082 1083 1084 1085
	client->addr = info->addr;
	client->irq = info->irq;

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

1086
	status = i2c_check_addr_validity(client->addr, client->flags);
1087 1088 1089 1090 1091 1092
	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;
	}

1093
	/* Check for address business */
1094
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1095 1096 1097 1098 1099
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
1100
	client->dev.type = &i2c_client_type;
1101
	client->dev.of_node = info->of_node;
1102
	client->dev.fwnode = info->fwnode;
1103

1104
	i2c_dev_set_name(adap, client);
1105 1106 1107 1108 1109 1110 1111
	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));

1112
	return client;
1113 1114 1115 1116

out_err:
	dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
		"(%d)\n", client->name, client->addr, status);
1117
out_err_silent:
1118 1119
	kfree(client);
	return NULL;
1120 1121 1122 1123 1124 1125 1126
}
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
1127
 * Context: can sleep
1128 1129
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
1130
{
1131 1132
	if (client->dev.of_node)
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
D
David Brownell 已提交
1133 1134
	device_unregister(&client->dev);
}
1135
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
1136 1137


J
Jean Delvare 已提交
1138 1139 1140 1141 1142
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

1143 1144 1145 1146 1147 1148 1149
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
1150 1151 1152 1153 1154 1155
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
1156 1157
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
1158
	.id_table	= dummy_id,
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178
};

/**
 * 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
1179
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1180 1181
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
1182
		I2C_BOARD_INFO("dummy", address),
1183 1184 1185 1186 1187 1188
	};

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

1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229
/**
 * i2c_new_secondary_device - Helper to get the instantiated secondary address
 * and create the associated device
 * @client: Handle to the primary client
 * @name: Handle to specify which secondary address to get
 * @default_addr: Used as a fallback if no secondary address was specified
 * Context: can sleep
 *
 * I2C clients can be composed of multiple I2C slaves bound together in a single
 * component. The I2C client driver then binds to the master I2C slave and needs
 * to create I2C dummy clients to communicate with all the other slaves.
 *
 * This function creates and returns an I2C dummy client whose I2C address is
 * retrieved from the platform firmware based on the given slave name. If no
 * address is specified by the firmware default_addr is used.
 *
 * On DT-based platforms the address is retrieved from the "reg" property entry
 * cell whose "reg-names" value matches the slave name.
 *
 * This returns the new i2c client, which should be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
						const char *name,
						u16 default_addr)
{
	struct device_node *np = client->dev.of_node;
	u32 addr = default_addr;
	int i;

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

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

1230 1231
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
1232 1233
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
1234
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
1235
{
1236
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
1237 1238 1239
	complete(&adap->dev_released);
}

1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255
/*
 * 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;
}

1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299
/*
 * 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;
	}

1300 1301 1302 1303 1304 1305 1306 1307 1308 1309
	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;
	}

1310 1311
	client = i2c_new_device(adap, &info);
	if (!client)
1312
		return -EINVAL;
1313 1314

	/* Keep track of the added device */
1315
	mutex_lock(&adap->userspace_clients_lock);
1316
	list_add_tail(&client->detected, &adap->userspace_clients);
1317
	mutex_unlock(&adap->userspace_clients_lock);
1318 1319 1320 1321 1322
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1323
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356

/*
 * 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;
1357 1358
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1359 1360
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1361
		if (i2c_encode_flags_to_addr(client) == addr) {
1362 1363 1364 1365 1366 1367 1368 1369 1370
			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;
		}
	}
1371
	mutex_unlock(&adap->userspace_clients_lock);
1372 1373 1374 1375 1376 1377

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1378 1379
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1380 1381 1382 1383 1384 1385 1386

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1387
ATTRIBUTE_GROUPS(i2c_adapter);
1388

1389
struct device_type i2c_adapter_type = {
1390
	.groups		= i2c_adapter_groups,
1391
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1392
};
1393
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1394

1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411
/**
 * 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);

1412 1413 1414 1415
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1416 1417 1418 1419
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1420
	down_read(&__i2c_board_lock);
1421 1422 1423 1424
	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
1425 1426
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1427 1428
				devinfo->board_info.addr);
	}
1429
	up_read(&__i2c_board_lock);
1430 1431
}

1432 1433 1434
/* OF support code */

#if IS_ENABLED(CONFIG_OF)
1435 1436
static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
						 struct device_node *node)
1437
{
1438 1439 1440
	struct i2c_client *result;
	struct i2c_board_info info = {};
	struct dev_archdata dev_ad = {};
W
Wolfram Sang 已提交
1441 1442
	const __be32 *addr_be;
	u32 addr;
1443
	int len;
1444

1445
	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1446

1447 1448 1449 1450 1451
	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);
	}
1452

W
Wolfram Sang 已提交
1453 1454
	addr_be = of_get_property(node, "reg", &len);
	if (!addr_be || (len < sizeof(*addr_be))) {
1455 1456 1457 1458
		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1459

W
Wolfram Sang 已提交
1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
	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)) {
1472 1473 1474 1475
		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
			info.addr, node->full_name);
		return ERR_PTR(-EINVAL);
	}
1476

W
Wolfram Sang 已提交
1477
	info.addr = addr;
1478 1479
	info.of_node = of_node_get(node);
	info.archdata = &dev_ad;
1480

1481 1482
	if (of_get_property(node, "wakeup-source", NULL))
		info.flags |= I2C_CLIENT_WAKE;
1483

1484 1485 1486 1487 1488 1489 1490 1491 1492
	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;
}
1493

1494 1495 1496
static void of_i2c_register_devices(struct i2c_adapter *adap)
{
	struct device_node *node;
1497

1498 1499 1500
	/* Only register child devices if the adapter has a node pointer set */
	if (!adap->dev.of_node)
		return;
1501

1502 1503
	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");

1504 1505 1506
	for_each_available_child_of_node(adap->dev.of_node, node) {
		if (of_node_test_and_set_flag(node, OF_POPULATED))
			continue;
1507
		of_i2c_register_device(adap, node);
1508
	}
1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519
}

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;
1520
	struct i2c_client *client;
1521

1522
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1523 1524 1525
	if (!dev)
		return NULL;

1526 1527 1528 1529 1530
	client = i2c_verify_client(dev);
	if (!client)
		put_device(dev);

	return client;
1531 1532 1533 1534 1535 1536 1537
}
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;
1538
	struct i2c_adapter *adapter;
1539

1540
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1541 1542 1543
	if (!dev)
		return NULL;

1544 1545 1546 1547 1548
	adapter = i2c_verify_adapter(dev);
	if (!adapter)
		put_device(dev);

	return adapter;
1549 1550
}
EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568

/* 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);
1569 1570 1571 1572
#else
static void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif /* CONFIG_OF */

J
Jean Delvare 已提交
1573 1574
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1575
{
1576 1577 1578 1579
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

	/* Let legacy drivers scan this bus for matching devices */
1580
	if (driver->attach_adapter) {
J
Jean Delvare 已提交
1581 1582
		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
			 driver->driver.name);
1583 1584
		dev_warn(&adap->dev, "Please use another way to instantiate "
			 "your i2c_client\n");
1585 1586 1587 1588 1589 1590
		/* We ignore the return code; if it fails, too bad */
		driver->attach_adapter(adap);
	}
	return 0;
}

J
Jean Delvare 已提交
1591 1592 1593 1594 1595
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1596
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1597
{
1598
	int res = -EINVAL;
L
Linus Torvalds 已提交
1599

1600
	/* Can't register until after driver model init */
1601
	if (WARN_ON(!is_registered)) {
1602 1603 1604
		res = -EAGAIN;
		goto out_list;
	}
1605

1606 1607 1608 1609
	/* Sanity checks */
	if (unlikely(adap->name[0] == '\0')) {
		pr_err("i2c-core: Attempt to register an adapter with "
		       "no name!\n");
1610
		goto out_list;
1611 1612 1613 1614
	}
	if (unlikely(!adap->algo)) {
		pr_err("i2c-core: Attempt to register adapter '%s' with "
		       "no algo!\n", adap->name);
1615
		goto out_list;
1616 1617
	}

1618 1619 1620 1621 1622 1623
	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;
	}

1624
	rt_mutex_init(&adap->bus_lock);
1625
	rt_mutex_init(&adap->mux_lock);
1626
	mutex_init(&adap->userspace_clients_lock);
1627
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
1628

1629 1630 1631 1632
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

1633
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1634 1635
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
1636 1637 1638
	res = device_register(&adap->dev);
	if (res)
		goto out_list;
L
Linus Torvalds 已提交
1639

1640 1641
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

1642
	pm_runtime_no_callbacks(&adap->dev);
1643
	pm_suspend_ignore_children(&adap->dev, true);
1644
	pm_runtime_enable(&adap->dev);
1645

1646 1647 1648 1649 1650 1651 1652 1653
#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

1654
	i2c_init_recovery(adap);
1655

1656
	/* create pre-declared device nodes */
1657
	of_i2c_register_devices(adap);
1658
	acpi_i2c_register_devices(adap);
1659
	acpi_i2c_install_space_handler(adap);
1660

1661 1662 1663
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

1664
	/* Notify drivers */
1665
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
1666
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
1667
	mutex_unlock(&core_lock);
1668 1669

	return 0;
1670 1671

out_list:
1672
	mutex_lock(&core_lock);
1673
	idr_remove(&i2c_adapter_idr, adap->nr);
1674 1675
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
1676 1677
}

1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698
/**
 * __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);
}

1699 1700 1701
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
1702
 * Context: can sleep
1703 1704
 *
 * This routine is used to declare an I2C adapter when its bus number
1705 1706 1707
 * 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.
1708 1709 1710 1711 1712 1713 1714
 *
 * 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)
{
1715
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
1716
	int id;
1717

1718 1719 1720 1721 1722 1723 1724 1725
	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
1726
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
1727 1728
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
1729
	mutex_unlock(&core_lock);
T
Tejun Heo 已提交
1730 1731
	if (id < 0)
		return id;
1732 1733

	adapter->nr = id;
T
Tejun Heo 已提交
1734

1735 1736 1737 1738 1739 1740 1741
	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
1742
 * Context: can sleep
1743 1744
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
1745 1746
 * 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
1747 1748
 * is used to properly configure I2C devices.
 *
1749 1750 1751
 * 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.
 *
1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763
 * 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)
{
1764 1765
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
1766

1767
	return __i2c_add_numbered_adapter(adap);
1768 1769 1770
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
1771
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
1772
			      struct i2c_adapter *adapter)
1773
{
1774
	struct i2c_client *client, *_n;
1775

1776 1777
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
1778 1779 1780 1781 1782 1783 1784 1785
	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);
		}
	}
1786 1787
}

1788
static int __unregister_client(struct device *dev, void *dummy)
1789 1790 1791 1792 1793 1794 1795 1796
{
	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)
1797 1798 1799 1800 1801 1802 1803
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client)
		i2c_unregister_device(client);
	return 0;
}

J
Jean Delvare 已提交
1804 1805
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
1806 1807
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
1808 1809
}

D
David Brownell 已提交
1810 1811 1812 1813 1814 1815 1816 1817
/**
 * 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.
 */
1818
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1819
{
1820
	struct i2c_adapter *found;
1821
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
1822 1823

	/* First make sure that this adapter was ever added */
1824 1825 1826 1827
	mutex_lock(&core_lock);
	found = idr_find(&i2c_adapter_idr, adap->nr);
	mutex_unlock(&core_lock);
	if (found != adap) {
1828 1829
		pr_debug("i2c-core: attempting to delete unregistered "
			 "adapter [%s]\n", adap->name);
1830
		return;
L
Linus Torvalds 已提交
1831 1832
	}

1833
	acpi_i2c_remove_space_handler(adap);
1834
	/* Tell drivers about this removal */
1835
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
1836
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
1837
			       __process_removed_adapter);
1838
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1839

1840
	/* Remove devices instantiated from sysfs */
1841 1842
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1843 1844 1845 1846 1847 1848
	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);
1849
	}
1850
	mutex_unlock(&adap->userspace_clients_lock);
1851

1852
	/* Detach any active clients. This can't fail, thus we do not
1853 1854 1855 1856
	 * 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
1857 1858
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
1859

1860 1861 1862 1863 1864
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

1865 1866 1867
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

1868 1869
	pm_runtime_disable(&adap->dev);

1870 1871 1872 1873 1874
	/* 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
1875
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1876
	 */
L
Linus Torvalds 已提交
1877 1878 1879 1880
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

1881
	/* free bus id */
1882
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
1883
	idr_remove(&i2c_adapter_idr, adap->nr);
1884
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1885

1886 1887 1888
	/* 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
1889
}
D
David Brownell 已提交
1890
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
1891

1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943
/**
 * 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
1944 1945
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957
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
1958
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
1959
{
1960 1961
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
1962
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
1963 1964
}

D
David Brownell 已提交
1965 1966
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1967
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
1968 1969
 */

1970
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
1971
{
1972
	int res;
L
Linus Torvalds 已提交
1973

1974
	/* Can't register until after driver model init */
1975
	if (WARN_ON(!is_registered))
1976 1977
		return -EAGAIN;

L
Linus Torvalds 已提交
1978
	/* add the driver to the list of i2c drivers in the driver core */
1979
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
1980 1981
	driver->driver.bus = &i2c_bus_type;

1982
	/* When registration returns, the driver core
1983 1984
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
1985 1986
	res = driver_register(&driver->driver);
	if (res)
1987
		return res;
D
David Brownell 已提交
1988

1989
	pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
1990

1991 1992
	INIT_LIST_HEAD(&driver->clients);
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
1993
	i2c_for_each_dev(driver, __process_new_driver);
1994

D
Dave Young 已提交
1995 1996 1997 1998
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
1999
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
2000
{
L
Lars-Peter Clausen 已提交
2001 2002 2003
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
2004 2005
}

D
David Brownell 已提交
2006 2007 2008
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
2009
 * Context: can sleep
D
David Brownell 已提交
2010
 */
2011
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
2012
{
J
Jean Delvare 已提交
2013
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
2014 2015

	driver_unregister(&driver->driver);
2016
	pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
2017
}
D
David Brownell 已提交
2018
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
2019

D
David Brownell 已提交
2020 2021
/* ------------------------------------------------------------------------- */

2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
/**
 * 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
2034
{
2035 2036 2037
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
2038
}
D
David Brownell 已提交
2039
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
2040

2041 2042 2043 2044 2045 2046 2047
/**
 * 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
2048
{
2049 2050
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
2051
}
D
David Brownell 已提交
2052
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
2053

2054 2055 2056 2057 2058 2059 2060 2061 2062
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;
2063 2064 2065 2066
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
2067

2068 2069 2070
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
2071 2072 2073
	return 0;
}

L
Linus Torvalds 已提交
2074 2075
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
2076
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
2077

2078 2079 2080
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
2081
}
D
David Brownell 已提交
2082
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
2083

2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097
#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 */

2098 2099 2100 2101 2102
		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
			put_device(&adap->dev);
			return NOTIFY_OK;
		}

2103 2104 2105 2106 2107 2108 2109 2110 2111 2112
		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:
2113 2114 2115 2116
		/* already depopulated? */
		if (!of_node_check_flag(rd->dn, OF_POPULATED))
			return NOTIFY_OK;

2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138
		/* 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
2139 2140 2141 2142
static int __init i2c_init(void)
{
	int retval;

2143 2144 2145 2146 2147 2148 2149
	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
2150 2151 2152
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
2153 2154 2155

	is_registered = true;

2156 2157 2158 2159 2160 2161 2162
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
2163 2164
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
2165
		goto class_err;
2166 2167 2168 2169

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

2170 2171
	return 0;

2172 2173 2174
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
2175
bus_err:
2176
#endif
2177
	is_registered = false;
2178 2179
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
2180 2181 2182 2183
}

static void __exit i2c_exit(void)
{
2184 2185
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2186
	i2c_del_driver(&dummy_driver);
2187 2188 2189
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
2190
	bus_unregister(&i2c_bus_type);
2191
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
2192 2193
}

D
David Brownell 已提交
2194 2195 2196 2197
/* 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
2198 2199 2200 2201 2202 2203 2204
module_exit(i2c_exit);

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

W
Wolfram Sang 已提交
2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263
/* 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;
}

2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280
/**
 * __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
2281 2282 2283
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296
	/* 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);
	}

2297 2298 2299 2300 2301 2302 2303 2304 2305 2306
	/* 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;
	}

2307 2308 2309 2310 2311 2312 2313 2314
	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);
	}

2315 2316 2317 2318
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330
/**
 * 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
2331
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
2332
{
2333
	int ret;
L
Linus Torvalds 已提交
2334

2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351
	/* 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
2352 2353 2354 2355
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
			dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
2356 2357 2358
				"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
2359 2360 2361
		}
#endif

2362
		if (in_atomic() || irqs_disabled()) {
2363
			ret = adap->trylock_bus(adap, I2C_LOCK_SEGMENT);
2364 2365 2366 2367
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
2368
			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
2369 2370
		}

2371
		ret = __i2c_transfer(adap, msgs, num);
2372
		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
2373 2374 2375 2376

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
2377
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
2378 2379
	}
}
D
David Brownell 已提交
2380
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
2381

2382 2383 2384 2385
/**
 * 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
2386
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2387 2388 2389
 *
 * Returns negative errno, or else the number of bytes written.
 */
2390
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
L
Linus Torvalds 已提交
2391 2392
{
	int ret;
2393
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2394 2395
	struct i2c_msg msg;

2396 2397 2398 2399
	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = (char *)buf;
D
David Brownell 已提交
2400

2401
	ret = i2c_transfer(adap, &msg, 1);
L
Linus Torvalds 已提交
2402

2403 2404 2405 2406
	/*
	 * If everything went ok (i.e. 1 msg transmitted), return #bytes
	 * transmitted, else error code.
	 */
2407
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2408
}
D
David Brownell 已提交
2409
EXPORT_SYMBOL(i2c_master_send);
L
Linus Torvalds 已提交
2410

2411 2412 2413 2414
/**
 * 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
2415
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2416 2417 2418
 *
 * Returns negative errno, or else the number of bytes read.
 */
2419
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
L
Linus Torvalds 已提交
2420
{
2421
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2422 2423
	struct i2c_msg msg;
	int ret;
2424 2425 2426 2427 2428 2429 2430 2431 2432

	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);

2433 2434 2435 2436
	/*
	 * If everything went ok (i.e. 1 msg received), return #bytes received,
	 * else error code.
	 */
2437
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2438
}
D
David Brownell 已提交
2439
EXPORT_SYMBOL(i2c_master_recv);
L
Linus Torvalds 已提交
2440 2441 2442 2443 2444 2445 2446

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

2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470
/*
 * 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
2471 2472
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2473 2474
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2475 2476 2477 2478
	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 {
2479 2480
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2481 2482
		err = -EOPNOTSUPP;
	}
2483 2484 2485 2486

	return err >= 0;
}

J
Jean Delvare 已提交
2487
static int i2c_detect_address(struct i2c_client *temp_client,
2488 2489 2490 2491 2492 2493 2494 2495
			      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 */
2496
	err = i2c_check_7bit_addr_validity_strict(addr);
2497
	if (err) {
2498 2499
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2500
		return err;
2501 2502
	}

2503
	/* Skip if already in use (7 bit, no need to encode flags) */
2504
	if (i2c_check_addr_busy(adapter, addr))
2505 2506
		return 0;

J
Jean Delvare 已提交
2507
	/* Make sure there is something at this address */
2508 2509
	if (!i2c_default_probe(adapter, addr))
		return 0;
2510 2511 2512 2513

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
2514
	err = driver->detect(temp_client, &info);
2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529
	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 */
2530 2531 2532 2533 2534 2535 2536
		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);

2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550
		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)
{
2551
	const unsigned short *address_list;
2552 2553 2554 2555
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

2556 2557
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
2558 2559
		return 0;

2560 2561 2562 2563 2564 2565 2566 2567 2568 2569
	/* 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
2570 2571 2572 2573
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

2574 2575 2576 2577 2578 2579
	/* 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;

2580
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2581
		dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2582 2583
			"addr 0x%02x\n", adap_id, address_list[i]);
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
2584
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
2585 2586
		if (unlikely(err))
			break;
2587 2588 2589 2590 2591 2592
	}

	kfree(temp_client);
	return err;
}

2593 2594 2595 2596 2597 2598 2599
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
2600 2601 2602
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
2603 2604
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
2605 2606 2607
{
	int i;

2608
	if (!probe)
2609
		probe = i2c_default_probe;
J
Jean Delvare 已提交
2610 2611 2612

	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
2613
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
J
Jean Delvare 已提交
2614 2615 2616 2617 2618
			dev_warn(&adap->dev, "Invalid 7-bit address "
				 "0x%02x\n", addr_list[i]);
			continue;
		}

2619
		/* Check address availability (7 bit, no need to encode flags) */
2620
		if (i2c_check_addr_busy(adap, addr_list[i])) {
J
Jean Delvare 已提交
2621 2622 2623 2624 2625
			dev_dbg(&adap->dev, "Address 0x%02x already in "
				"use, not probing\n", addr_list[i]);
			continue;
		}

2626
		/* Test address responsiveness */
2627
		if (probe(adap, addr_list[i]))
2628
			break;
J
Jean Delvare 已提交
2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640
	}

	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);

2641
struct i2c_adapter *i2c_get_adapter(int nr)
L
Linus Torvalds 已提交
2642 2643
{
	struct i2c_adapter *adapter;
D
David Brownell 已提交
2644

J
Jean Delvare 已提交
2645
	mutex_lock(&core_lock);
2646
	adapter = idr_find(&i2c_adapter_idr, nr);
2647 2648 2649 2650 2651 2652
	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
2653 2654
		adapter = NULL;

2655
 exit:
J
Jean Delvare 已提交
2656
	mutex_unlock(&core_lock);
2657
	return adapter;
L
Linus Torvalds 已提交
2658
}
D
David Brownell 已提交
2659
EXPORT_SYMBOL(i2c_get_adapter);
L
Linus Torvalds 已提交
2660 2661 2662

void i2c_put_adapter(struct i2c_adapter *adap)
{
2663 2664 2665 2666 2667
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
L
Linus Torvalds 已提交
2668
}
D
David Brownell 已提交
2669
EXPORT_SYMBOL(i2c_put_adapter);
L
Linus Torvalds 已提交
2670 2671 2672

/* The SMBus parts */

D
David Brownell 已提交
2673
#define POLY    (0x1070U << 3)
Z
Zhenwen Xu 已提交
2674
static u8 crc8(u16 data)
L
Linus Torvalds 已提交
2675 2676
{
	int i;
D
David Brownell 已提交
2677

2678
	for (i = 0; i < 8; i++) {
D
David Brownell 已提交
2679
		if (data & 0x8000)
L
Linus Torvalds 已提交
2680 2681 2682 2683 2684 2685
			data = data ^ POLY;
		data = data << 1;
	}
	return (u8)(data >> 8);
}

2686 2687
/* 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
2688 2689 2690
{
	int i;

2691
	for (i = 0; i < count; i++)
2692
		crc = crc8((crc ^ p[i]) << 8);
L
Linus Torvalds 已提交
2693 2694 2695
	return crc;
}

2696 2697
/* 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
2698
{
2699
	/* The address will be sent first */
2700
	u8 addr = i2c_8bit_addr_from_msg(msg);
2701 2702 2703 2704
	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
2705 2706
}

2707 2708
/* Used for write only transactions */
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
L
Linus Torvalds 已提交
2709
{
2710 2711
	msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
	msg->len++;
L
Linus Torvalds 已提交
2712 2713
}

2714 2715 2716 2717 2718 2719
/* 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
2720
{
2721 2722
	u8 rpec = msg->buf[--msg->len];
	cpec = i2c_smbus_msg_pec(cpec, msg);
L
Linus Torvalds 已提交
2723 2724 2725 2726

	if (rpec != cpec) {
		pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
			rpec, cpec);
D
David Brownell 已提交
2727
		return -EBADMSG;
L
Linus Torvalds 已提交
2728
	}
D
David Brownell 已提交
2729
	return 0;
L
Linus Torvalds 已提交
2730 2731
}

2732 2733 2734 2735 2736 2737 2738
/**
 * 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.
 */
2739
s32 i2c_smbus_read_byte(const struct i2c_client *client)
L
Linus Torvalds 已提交
2740 2741
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2742 2743 2744 2745 2746 2747
	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
2748
}
D
David Brownell 已提交
2749
EXPORT_SYMBOL(i2c_smbus_read_byte);
L
Linus Torvalds 已提交
2750

2751 2752 2753 2754 2755 2756 2757 2758
/**
 * 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.
 */
2759
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
L
Linus Torvalds 已提交
2760
{
2761
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2762
	                      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
L
Linus Torvalds 已提交
2763
}
D
David Brownell 已提交
2764
EXPORT_SYMBOL(i2c_smbus_write_byte);
L
Linus Torvalds 已提交
2765

2766 2767 2768 2769 2770 2771 2772 2773
/**
 * 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.
 */
2774
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2775 2776
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2777 2778 2779 2780 2781 2782
	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
2783
}
D
David Brownell 已提交
2784
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
L
Linus Torvalds 已提交
2785

2786 2787 2788 2789 2790 2791 2792 2793 2794
/**
 * 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.
 */
2795 2796
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
			      u8 value)
L
Linus Torvalds 已提交
2797 2798 2799
{
	union i2c_smbus_data data;
	data.byte = value;
2800 2801 2802
	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
2803
}
D
David Brownell 已提交
2804
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
L
Linus Torvalds 已提交
2805

2806 2807 2808 2809 2810 2811 2812 2813
/**
 * 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.
 */
2814
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2815 2816
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2817 2818 2819 2820 2821 2822
	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
2823
}
D
David Brownell 已提交
2824
EXPORT_SYMBOL(i2c_smbus_read_word_data);
L
Linus Torvalds 已提交
2825

2826 2827 2828 2829 2830 2831 2832 2833 2834
/**
 * 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.
 */
2835 2836
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
			      u16 value)
L
Linus Torvalds 已提交
2837 2838 2839
{
	union i2c_smbus_data data;
	data.word = value;
2840 2841 2842
	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
2843
}
D
David Brownell 已提交
2844
EXPORT_SYMBOL(i2c_smbus_write_word_data);
L
Linus Torvalds 已提交
2845

D
David Brownell 已提交
2846
/**
2847
 * i2c_smbus_read_block_data - SMBus "block read" protocol
D
David Brownell 已提交
2848
 * @client: Handle to slave device
2849
 * @command: Byte interpreted by slave
D
David Brownell 已提交
2850 2851 2852
 * @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.
 *
2853 2854
 * 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
2855 2856 2857 2858 2859 2860
 *
 * 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.
 */
2861
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2862 2863 2864
			      u8 *values)
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2865
	int status;
2866

D
David Brownell 已提交
2867 2868 2869 2870 2871
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BLOCK_DATA, &data);
	if (status)
		return status;
2872 2873 2874 2875 2876 2877

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

2878 2879 2880 2881 2882 2883 2884 2885 2886 2887
/**
 * 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.
 */
2888
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2889
			       u8 length, const u8 *values)
L
Linus Torvalds 已提交
2890 2891
{
	union i2c_smbus_data data;
2892

L
Linus Torvalds 已提交
2893 2894 2895
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
2896
	memcpy(&data.block[1], values, length);
2897 2898 2899
	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
2900
}
D
David Brownell 已提交
2901
EXPORT_SYMBOL(i2c_smbus_write_block_data);
L
Linus Torvalds 已提交
2902 2903

/* Returns the number of read bytes */
2904
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2905
				  u8 length, u8 *values)
L
Linus Torvalds 已提交
2906 2907
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2908
	int status;
2909

2910 2911 2912
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
D
David Brownell 已提交
2913 2914 2915 2916 2917
	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;
2918 2919 2920

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
L
Linus Torvalds 已提交
2921
}
D
David Brownell 已提交
2922
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
L
Linus Torvalds 已提交
2923

2924
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2925
				   u8 length, const u8 *values)
2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936
{
	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
2937
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2938

D
David Brownell 已提交
2939
/* Simulate a SMBus command using the i2c protocol
L
Linus Torvalds 已提交
2940
   No checking of parameters is done!  */
2941 2942 2943 2944
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
2945 2946 2947 2948 2949
{
	/* 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. */
2950 2951
	unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
	unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2952
	int num = read_write == I2C_SMBUS_READ ? 2 : 1;
L
Linus Torvalds 已提交
2953
	int i;
2954
	u8 partial_pec = 0;
D
David Brownell 已提交
2955
	int status;
2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968
	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
2969 2970

	msgbuf0[0] = command;
2971
	switch (size) {
L
Linus Torvalds 已提交
2972 2973 2974
	case I2C_SMBUS_QUICK:
		msg[0].len = 0;
		/* Special case: The read/write field is used as data */
R
Roel Kluin 已提交
2975 2976
		msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
					I2C_M_RD : 0);
L
Linus Torvalds 已提交
2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997
		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 {
2998
			msg[0].len = 3;
L
Linus Torvalds 已提交
2999
			msgbuf0[1] = data->word & 0xff;
3000
			msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
3001 3002 3003 3004 3005 3006 3007 3008
		}
		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;
3009
		msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
3010 3011 3012
		break;
	case I2C_SMBUS_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
3013 3014 3015
			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
3016 3017 3018
		} else {
			msg[0].len = data->block[0] + 2;
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
D
David Brownell 已提交
3019 3020 3021 3022
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3023
			}
3024
			for (i = 1; i < msg[0].len; i++)
L
Linus Torvalds 已提交
3025 3026 3027 3028
				msgbuf0[i] = data->block[i-1];
		}
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
3029 3030 3031
		num = 2; /* Another special case */
		read_write = I2C_SMBUS_READ;
		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
D
David Brownell 已提交
3032 3033
			dev_err(&adapter->dev,
				"Invalid block write size %d\n",
3034
				data->block[0]);
D
David Brownell 已提交
3035
			return -EINVAL;
3036 3037 3038 3039 3040 3041 3042 3043
		}
		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
3044 3045
	case I2C_SMBUS_I2C_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
3046
			msg[1].len = data->block[0];
L
Linus Torvalds 已提交
3047 3048
		} else {
			msg[0].len = data->block[0] + 1;
3049
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
D
David Brownell 已提交
3050 3051 3052 3053
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3054 3055 3056 3057 3058 3059
			}
			for (i = 1; i <= data->block[0]; i++)
				msgbuf0[i] = data->block[i];
		}
		break;
	default:
D
David Brownell 已提交
3060 3061
		dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
3062 3063
	}

3064 3065 3066 3067 3068
	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
3069
			if (num == 1) /* Write only */
3070 3071 3072 3073 3074 3075
				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
3076
			msg[num-1].len++;
3077 3078
	}

D
David Brownell 已提交
3079 3080 3081
	status = i2c_transfer(adapter, msg, num);
	if (status < 0)
		return status;
L
Linus Torvalds 已提交
3082

3083 3084
	/* Check PEC if last message is a read */
	if (i && (msg[num-1].flags & I2C_M_RD)) {
D
David Brownell 已提交
3085 3086 3087
		status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
		if (status < 0)
			return status;
3088 3089
	}

L
Linus Torvalds 已提交
3090
	if (read_write == I2C_SMBUS_READ)
3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110
		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
3111 3112 3113 3114
		}
	return 0;
}

3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127
/**
 * 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
3128
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3129
		   char read_write, u8 command, int protocol,
Z
Zhenwen Xu 已提交
3130
		   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
3131
{
3132 3133
	unsigned long orig_jiffies;
	int try;
L
Linus Torvalds 已提交
3134 3135
	s32 res;

3136 3137 3138 3139 3140 3141 3142 3143
	/* 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
3144
	flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
L
Linus Torvalds 已提交
3145 3146

	if (adapter->algo->smbus_xfer) {
3147
		i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160

		/* 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;
		}
3161
		i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
3162

3163
		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3164
			goto trace;
3165 3166 3167 3168 3169 3170
		/*
		 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
		 * implement native support for the SMBus operation.
		 */
	}

3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181
	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
3182 3183 3184
}
EXPORT_SYMBOL(i2c_smbus_xfer);

3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241
/**
 * 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);

3242
#if IS_ENABLED(CONFIG_I2C_SLAVE)
W
Wolfram Sang 已提交
3243 3244 3245 3246
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
	int ret;

3247 3248
	if (!client || !slave_cb) {
		WARN(1, "insufficent data\n");
W
Wolfram Sang 已提交
3249
		return -EINVAL;
3250
	}
W
Wolfram Sang 已提交
3251

3252 3253 3254 3255
	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
3256 3257
	if (!(client->flags & I2C_CLIENT_TEN)) {
		/* Enforce stricter address checking */
3258
		ret = i2c_check_7bit_addr_validity_strict(client->addr);
3259 3260
		if (ret) {
			dev_err(&client->dev, "%s: invalid address\n", __func__);
W
Wolfram Sang 已提交
3261
			return ret;
3262
		}
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	}

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	if (!client->adapter->algo->reg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
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		return -EOPNOTSUPP;
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	}
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	client->slave_cb = slave_cb;

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

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	if (ret) {
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		client->slave_cb = NULL;
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		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
	}
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	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_register);

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

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	if (!client->adapter->algo->unreg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
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		return -EOPNOTSUPP;
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	}
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	i2c_lock_adapter(client->adapter);
	ret = client->adapter->algo->unreg_slave(client);
	i2c_unlock_adapter(client->adapter);

	if (ret == 0)
		client->slave_cb = NULL;
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	else
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
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	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
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#endif
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MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");