i2c-core-base.c

/* 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
    GNU General Public License for more details.			     */
/* ------------------------------------------------------------------------- */

/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   Michael Lawnick <michael.lawnick.ext@nsn.com>
   I2C ACPI code Copyright (C) 2014 Intel Corp
   Author: Lan Tianyu <tianyu.lan@intel.com>
 */

#define pr_fmt(fmt) "i2c-core: " fmt

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

#include "i2c-core.h"

#define CREATE_TRACE_POINTS
#include <trace/events/i2c.h>

#define I2C_ADDR_OFFSET_TEN_BIT	0xa000
#define I2C_ADDR_OFFSET_SLAVE	0x1000

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

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

static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);

static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
static bool is_registered;

int i2c_transfer_trace_reg(void)
{
	static_key_slow_inc(&i2c_trace_msg);
	return 0;
}

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

#if defined(CONFIG_ACPI)
struct i2c_acpi_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;

struct i2c_acpi_lookup {
	struct i2c_board_info *info;
	acpi_handle adapter_handle;
	acpi_handle device_handle;
	acpi_handle search_handle;
	int n;
	int index;
	u32 speed;
	u32 min_speed;
};

static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
{
	struct i2c_acpi_lookup *lookup = data;
	struct i2c_board_info *info = lookup->info;
	struct acpi_resource_i2c_serialbus *sb;
	acpi_status status;

	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;

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

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

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

	return 1;
}

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

	if (acpi_bus_get_status(adev) || !adev->status.present ||
	    acpi_device_enumerated(adev))
		return -EINVAL;

	memset(info, 0, sizeof(*info));
	lookup->device_handle = acpi_device_handle(adev);

	/* Look up for I2cSerialBus resource */
	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list,
				     i2c_acpi_fill_info, lookup);
	acpi_dev_free_resource_list(&resource_list);

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

	return 0;
}

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

	memset(&lookup, 0, sizeof(lookup));
	lookup.info = info;
	lookup.index = -1;

	ret = i2c_acpi_do_lookup(adev, &lookup);
	if (ret)
		return ret;

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

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

	info->fwnode = acpi_fwnode_handle(adev);
	if (adapter_handle)
		*adapter_handle = lookup.adapter_handle;

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

	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);

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

	return 0;
}

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

	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));
	}
}

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

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

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

	i2c_acpi_register_device(adapter, adev, &info);

	return AE_OK;
}

#define I2C_ACPI_MAX_SCAN_DEPTH 32

/**
 * i2c_acpi_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 i2c_acpi_register_devices(struct i2c_adapter *adap)
{
	acpi_status status;

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

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

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

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

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

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

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

	return AE_OK;
}

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

	if (!has_acpi_companion(dev))
		return 0;

	memset(&lookup, 0, sizeof(lookup));
	lookup.search_handle = ACPI_HANDLE(dev);
	lookup.min_speed = UINT_MAX;
	lookup.info = &dummy;
	lookup.index = -1;

	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
				     I2C_ACPI_MAX_SCAN_DEPTH,
				     i2c_acpi_lookup_speed, NULL,
				     &lookup, NULL);

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

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

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

	if (!adapter)
		return 0;

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

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

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

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

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

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

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

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

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

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

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

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

	return NOTIFY_OK;
}

static struct notifier_block i2c_acpi_notifier = {
	.notifier_call = i2c_acpi_notify,
};

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

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

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

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

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

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

	return i2c_new_device(adapter, info);
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
#else /* CONFIG_ACPI */
static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
extern struct notifier_block i2c_acpi_notifier;
#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
i2c_acpi_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 i2c_acpi_handler_data *data = handler_context;
	struct acpi_connection_info *info = &data->info;
	struct acpi_resource_i2c_serialbus *sb;
	struct i2c_adapter *adapter = data->adapter;
	struct i2c_client *client;
	struct acpi_resource *ares;
	u32 accessor_type = function >> 16;
	u8 action = function & ACPI_IO_MASK;
	acpi_status ret;
	int status;

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

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

	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;
	}

	client->adapter = adapter;
	client->addr = sb->slave_address;

	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
		client->flags |= I2C_CLIENT_TEN;

	switch (accessor_type) {
	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
		if (action == ACPI_READ) {
			status = i2c_smbus_read_byte(client);
			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
			status = i2c_smbus_write_byte(client, gsb->bdata);
		}
		break;

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

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

	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
		if (action == ACPI_READ) {
			status = i2c_smbus_read_block_data(client, command,
					gsb->data);
			if (status >= 0) {
				gsb->len = status;
				status = 0;
			}
		} else {
			status = i2c_smbus_write_block_data(client, command,
					gsb->len, gsb->data);
		}
		break;

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

	default:
		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
			 accessor_type, client->addr);
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	gsb->status = status;

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


static int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
{
	acpi_handle handle;
	struct i2c_acpi_handler_data *data;
	acpi_status status;

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

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

	if (!handle)
		return -ENODEV;

	data = kzalloc(sizeof(struct i2c_acpi_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,
				&i2c_acpi_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;
	}

	acpi_walk_dep_device_list(handle);
	return 0;
}

static void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
{
	acpi_handle handle;
	struct i2c_acpi_handler_data *data;
	acpi_status status;

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

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

	if (!handle)
		return;

	acpi_remove_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
				&i2c_acpi_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 i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
{ }

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

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

const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
						const struct i2c_client *client)
{
	if (!(id && client))
		return NULL;

	while (id->name[0]) {
		if (strcmp(client->name, id->name) == 0)
			return id;
		id++;
	}
	return NULL;
}
EXPORT_SYMBOL_GPL(i2c_match_id);

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


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

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

	driver = to_i2c_driver(drv);

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

	return 0;
}

static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct i2c_client *client = to_i2c_client(dev);
	int rc;

	rc = acpi_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;

	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
}

/* 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)
		bri->prepare_recovery(adap);

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

	/*
	 * 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)
		bri->unprepare_recovery(adap);

	return ret;
}

int i2c_generic_scl_recovery(struct i2c_adapter *adap)
{
	return i2c_generic_recovery(adap);
}
EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);

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;
}
EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);

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);
}
EXPORT_SYMBOL_GPL(i2c_recover_bus);

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;
}

static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
{
	struct i2c_adapter *adap = client->adapter;
	unsigned int irq;

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

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

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

	return irq > 0 ? irq : -ENXIO;
}

static int i2c_device_probe(struct device *dev)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
	int status;

	if (!client)
		return 0;

	driver = to_i2c_driver(dev->driver);

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

		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
			dev_dbg(dev, "Using Host Notify IRQ\n");
			irq = i2c_smbus_host_notify_to_irq(client);
		} else if (dev->of_node) {
			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)) {
			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
		}
		if (irq == -EPROBE_DEFER)
			return irq;

		if (irq < 0)
			irq = 0;

		client->irq = irq;
	}

	/*
	 * An I2C ID table is not mandatory, if and only if, a suitable Device
	 * Tree match table entry is supplied for the probing device.
	 */
	if (!driver->id_table &&
	    !i2c_of_match_device(dev->driver->of_match_table, client))
		return -ENODEV;

	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)
			status = dev_pm_set_wake_irq(dev, client->irq);
		else
			status = 0;

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

	dev_dbg(dev, "probe\n");

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

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

	/*
	 * When there are no more users of probe(),
	 * rename probe_new to probe.
	 */
	if (driver->probe_new)
		status = driver->probe_new(client);
	else if (driver->probe)
		status = driver->probe(client,
				       i2c_match_id(driver->id_table, client));
	else
		status = -EINVAL;

	if (status)
		goto err_detach_pm_domain;

	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);
	return status;
}

static int i2c_device_remove(struct device *dev)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
	int status = 0;

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

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

	dev_pm_domain_detach(&client->dev, true);

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

	return status;
}

static void i2c_device_shutdown(struct device *dev)
{
	struct i2c_client *client = i2c_verify_client(dev);
	struct i2c_driver *driver;

	if (!client || !dev->driver)
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
		driver->shutdown(client);
}

static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

static ssize_t
show_name(struct device *dev, struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
}
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	int len;

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

	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
}
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static struct attribute *i2c_dev_attrs[] = {
	&dev_attr_name.attr,
	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
	&dev_attr_modalias.attr,
	NULL
};
ATTRIBUTE_GROUPS(i2c_dev);

struct bus_type i2c_bus_type = {
	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
};
EXPORT_SYMBOL_GPL(i2c_bus_type);

struct device_type i2c_client_type = {
	.groups		= i2c_dev_groups,
	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};
EXPORT_SYMBOL_GPL(i2c_client_type);


/**
 * 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)
{
	return (dev->type == &i2c_client_type)
			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


/* 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;
}

/* This is a permissive address validity check, I2C address map constraints
 * are purposely not enforced, except for the general call address. */
int i2c_check_addr_validity(unsigned addr, unsigned short flags)
{
	if (flags & I2C_CLIENT_TEN) {
		/* 10-bit address, all values are valid */
		if (addr > 0x3ff)
			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
		if (addr == 0x00 || addr > 0x7f)
			return -EINVAL;
	}
	return 0;
}

/* 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. */
int i2c_check_7bit_addr_validity_strict(unsigned short addr)
{
	/*
	 * 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;
}

static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

	if (client && i2c_encode_flags_to_addr(client) == addr)
		return -EBUSY;
	return 0;
}

/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
	int result;

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

	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);

	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;
}

static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
	int result =