drivers/misc/isl29003.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  isl29003.c - Linux kernel module for
  * 	Intersil ISL29003 ambient light sensor
  *
  *  See file:Documentation/misc-devices/isl29003.rst
  *
  *  Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
  *
  *  Based on code written by
  *  	Rodolfo Giometti <giometti@linux.it>
  *  	Eurotech S.p.A. <info@eurotech.it>
  */

 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/mutex.h>
 #include <linux/delay.h>

 #define ISL29003_DRV_NAME	"isl29003"
 #define DRIVER_VERSION		"1.0"

 #define ISL29003_REG_COMMAND		0x00
 #define ISL29003_ADC_ENABLED		(1 << 7)
 #define ISL29003_ADC_PD			(1 << 6)
 #define ISL29003_TIMING_INT		(1 << 5)
 #define ISL29003_MODE_SHIFT		(2)
 #define ISL29003_MODE_MASK		(0x3 << ISL29003_MODE_SHIFT)
 #define ISL29003_RES_SHIFT		(0)
 #define ISL29003_RES_MASK		(0x3 << ISL29003_RES_SHIFT)

 #define ISL29003_REG_CONTROL		0x01
 #define ISL29003_INT_FLG		(1 << 5)
 #define ISL29003_RANGE_SHIFT		(2)
 #define ISL29003_RANGE_MASK		(0x3 << ISL29003_RANGE_SHIFT)
 #define ISL29003_INT_PERSISTS_SHIFT	(0)
 #define ISL29003_INT_PERSISTS_MASK	(0xf << ISL29003_INT_PERSISTS_SHIFT)

 #define ISL29003_REG_IRQ_THRESH_HI	0x02
 #define ISL29003_REG_IRQ_THRESH_LO	0x03
 #define ISL29003_REG_LSB_SENSOR		0x04
 #define ISL29003_REG_MSB_SENSOR		0x05
 #define ISL29003_REG_LSB_TIMER		0x06
 #define ISL29003_REG_MSB_TIMER		0x07

 #define ISL29003_NUM_CACHABLE_REGS	4

 struct isl29003_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	u8 reg_cache[ISL29003_NUM_CACHABLE_REGS];
 	u8 power_state_before_suspend;
 };

 static int gain_range[] = {
 	1000, 4000, 16000, 64000
 };

 /*
  * register access helpers
  */

 static int __isl29003_read_reg(struct i2c_client *client,
 			       u32 reg, u8 mask, u8 shift)
 {
 	struct isl29003_data *data = i2c_get_clientdata(client);

 	return (data->reg_cache[reg] & mask) >> shift;
 }

 static int __isl29003_write_reg(struct i2c_client *client,
 				u32 reg, u8 mask, u8 shift, u8 val)
 {
 	struct isl29003_data *data = i2c_get_clientdata(client);
 	int ret = 0;
 	u8 tmp;

 	if (reg >= ISL29003_NUM_CACHABLE_REGS)
 		return -EINVAL;

 	mutex_lock(&data->lock);

 	tmp = data->reg_cache[reg];
 	tmp &= ~mask;
 	tmp |= val << shift;

 	ret = i2c_smbus_write_byte_data(client, reg, tmp);
 	if (!ret)
 		data->reg_cache[reg] = tmp;

 	mutex_unlock(&data->lock);
 	return ret;
 }

 /*
  * internally used functions
  */

 /* range */
 static int isl29003_get_range(struct i2c_client *client)
 {
 	return __isl29003_read_reg(client, ISL29003_REG_CONTROL,
 		ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT);
 }

 static int isl29003_set_range(struct i2c_client *client, int range)
 {
 	return __isl29003_write_reg(client, ISL29003_REG_CONTROL,
 		ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT, range);
 }

 /* resolution */
 static int isl29003_get_resolution(struct i2c_client *client)
 {
 	return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
 		ISL29003_RES_MASK, ISL29003_RES_SHIFT);
 }

 static int isl29003_set_resolution(struct i2c_client *client, int res)
 {
 	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
 		ISL29003_RES_MASK, ISL29003_RES_SHIFT, res);
 }

 /* mode */
 static int isl29003_get_mode(struct i2c_client *client)
 {
 	return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
 		ISL29003_MODE_MASK, ISL29003_MODE_SHIFT);
 }

 static int isl29003_set_mode(struct i2c_client *client, int mode)
 {
 	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
 		ISL29003_MODE_MASK, ISL29003_MODE_SHIFT, mode);
 }

 /* power_state */
 static int isl29003_set_power_state(struct i2c_client *client, int state)
 {
 	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
 				ISL29003_ADC_ENABLED | ISL29003_ADC_PD, 0,
 				state ? ISL29003_ADC_ENABLED : ISL29003_ADC_PD);
 }

 static int isl29003_get_power_state(struct i2c_client *client)
 {
 	struct isl29003_data *data = i2c_get_clientdata(client);
 	u8 cmdreg = data->reg_cache[ISL29003_REG_COMMAND];

 	return ~cmdreg & ISL29003_ADC_PD;
 }

 static int isl29003_get_adc_value(struct i2c_client *client)
 {
 	struct isl29003_data *data = i2c_get_clientdata(client);
 	int lsb, msb, range, bitdepth;

 	mutex_lock(&data->lock);
 	lsb = i2c_smbus_read_byte_data(client, ISL29003_REG_LSB_SENSOR);

 	if (lsb < 0) {
 		mutex_unlock(&data->lock);
 		return lsb;
 	}

 	msb = i2c_smbus_read_byte_data(client, ISL29003_REG_MSB_SENSOR);
 	mutex_unlock(&data->lock);

 	if (msb < 0)
 		return msb;

 	range = isl29003_get_range(client);
 	bitdepth = (4 - isl29003_get_resolution(client)) * 4;
 	return (((msb << 8) | lsb) * gain_range[range]) >> bitdepth;
 }

 /*
  * sysfs layer
  */

 /* range */
 static ssize_t isl29003_show_range(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
 	struct i2c_client *client = to_i2c_client(dev);

 	return sprintf(buf, "%i\n", isl29003_get_range(client));
 }

 static ssize_t isl29003_store_range(struct device *dev,
 				    struct device_attribute *attr,
 				    const char *buf, size_t count)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned long val;
 	int ret;

 	ret = kstrtoul(buf, 10, &val);
 	if (ret)
 		return ret;

 	if (val > 3)
 		return -EINVAL;

 	ret = isl29003_set_range(client, val);
 	if (ret < 0)
 		return ret;

 	return count;
 }

 static DEVICE_ATTR(range, S_IWUSR | S_IRUGO,
 		   isl29003_show_range, isl29003_store_range);


 /* resolution */
 static ssize_t isl29003_show_resolution(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
 {
 	struct i2c_client *client = to_i2c_client(dev);

 	return sprintf(buf, "%d\n", isl29003_get_resolution(client));
 }

 static ssize_t isl29003_store_resolution(struct device *dev,
 					 struct device_attribute *attr,
 					 const char *buf, size_t count)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned long val;
 	int ret;

 	ret = kstrtoul(buf, 10, &val);
 	if (ret)
 		return ret;

 	if (val > 3)
 		return -EINVAL;

 	ret = isl29003_set_resolution(client, val);
 	if (ret < 0)
 		return ret;

 	return count;
 }

 static DEVICE_ATTR(resolution, S_IWUSR | S_IRUGO,
 		   isl29003_show_resolution, isl29003_store_resolution);

 /* mode */
 static ssize_t isl29003_show_mode(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
 	struct i2c_client *client = to_i2c_client(dev);

 	return sprintf(buf, "%d\n", isl29003_get_mode(client));
 }

 static ssize_t isl29003_store_mode(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned long val;
 	int ret;

 	ret = kstrtoul(buf, 10, &val);
 	if (ret)
 		return ret;

 	if (val > 2)
 		return -EINVAL;

 	ret = isl29003_set_mode(client, val);
 	if (ret < 0)
 		return ret;

 	return count;
 }

 static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
 		   isl29003_show_mode, isl29003_store_mode);


 /* power state */
 static ssize_t isl29003_show_power_state(struct device *dev,
 					 struct device_attribute *attr,
 					 char *buf)
 {
 	struct i2c_client *client = to_i2c_client(dev);

 	return sprintf(buf, "%d\n", isl29003_get_power_state(client));
 }

 static ssize_t isl29003_store_power_state(struct device *dev,
 					  struct device_attribute *attr,
 					  const char *buf, size_t count)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned long val;
 	int ret;

 	ret = kstrtoul(buf, 10, &val);
 	if (ret)
 		return ret;

 	if (val > 1)
 		return -EINVAL;

 	ret = isl29003_set_power_state(client, val);
 	return ret ? ret : count;
 }

 static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
 		   isl29003_show_power_state, isl29003_store_power_state);


 /* lux */
 static ssize_t isl29003_show_lux(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
 	struct i2c_client *client = to_i2c_client(dev);

 	/* No LUX data if not operational */
 	if (!isl29003_get_power_state(client))
 		return -EBUSY;

 	return sprintf(buf, "%d\n", isl29003_get_adc_value(client));
 }

 static DEVICE_ATTR(lux, S_IRUGO, isl29003_show_lux, NULL);

 static struct attribute *isl29003_attributes[] = {
 	&dev_attr_range.attr,
 	&dev_attr_resolution.attr,
 	&dev_attr_mode.attr,
 	&dev_attr_power_state.attr,
 	&dev_attr_lux.attr,
 	NULL
 };

 static const struct attribute_group isl29003_attr_group = {
 	.attrs = isl29003_attributes,
 };

 static int isl29003_init_client(struct i2c_client *client)
 {
 	struct isl29003_data *data = i2c_get_clientdata(client);
 	int i;

 	/* read all the registers once to fill the cache.
 	 * if one of the reads fails, we consider the init failed */
 	for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++) {
 		int v = i2c_smbus_read_byte_data(client, i);

 		if (v < 0)
 			return -ENODEV;

 		data->reg_cache[i] = v;
 	}

 	/* set defaults */
 	isl29003_set_range(client, 0);
 	isl29003_set_resolution(client, 0);
 	isl29003_set_mode(client, 0);
 	isl29003_set_power_state(client, 0);

 	return 0;
 }

 /*
  * I2C layer
  */

 static int isl29003_probe(struct i2c_client *client,
 				    const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	struct isl29003_data *data;
 	int err = 0;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 		return -EIO;

 	data = kzalloc(sizeof(struct isl29003_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->client = client;
 	i2c_set_clientdata(client, data);
 	mutex_init(&data->lock);

 	/* initialize the ISL29003 chip */
 	err = isl29003_init_client(client);
 	if (err)
 		goto exit_kfree;

 	/* register sysfs hooks */
 	err = sysfs_create_group(&client->dev.kobj, &isl29003_attr_group);
 	if (err)
 		goto exit_kfree;

 	dev_info(&client->dev, "driver version %s enabled\n", DRIVER_VERSION);
 	return 0;

 exit_kfree:
 	kfree(data);
 	return err;
 }

 static int isl29003_remove(struct i2c_client *client)
 {
 	sysfs_remove_group(&client->dev.kobj, &isl29003_attr_group);
 	isl29003_set_power_state(client, 0);
 	kfree(i2c_get_clientdata(client));
 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int isl29003_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct isl29003_data *data = i2c_get_clientdata(client);

 	data->power_state_before_suspend = isl29003_get_power_state(client);
 	return isl29003_set_power_state(client, 0);
 }

 static int isl29003_resume(struct device *dev)
 {
 	int i;
 	struct i2c_client *client = to_i2c_client(dev);
 	struct isl29003_data *data = i2c_get_clientdata(client);

 	/* restore registers from cache */
 	for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++)
 		if (i2c_smbus_write_byte_data(client, i, data->reg_cache[i]))
 			return -EIO;

 	return isl29003_set_power_state(client,
 		data->power_state_before_suspend);
 }

 static SIMPLE_DEV_PM_OPS(isl29003_pm_ops, isl29003_suspend, isl29003_resume);
 #define ISL29003_PM_OPS (&isl29003_pm_ops)

 #else
 #define ISL29003_PM_OPS NULL
 #endif /* CONFIG_PM_SLEEP */

 static const struct i2c_device_id isl29003_id[] = {
 	{ "isl29003", 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, isl29003_id);

 static struct i2c_driver isl29003_driver = {
 	.driver = {
 		.name	= ISL29003_DRV_NAME,
 		.pm	= ISL29003_PM_OPS,
 	},
 	.probe	= isl29003_probe,
 	.remove	= isl29003_remove,
 	.id_table = isl29003_id,
 };

 module_i2c_driver(isl29003_driver);

 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 MODULE_DESCRIPTION("ISL29003 ambient light sensor driver");
 MODULE_LICENSE("GPL v2");
 MODULE_VERSION(DRIVER_VERSION);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* isl29003.c - Linux kernel module for
	* Intersil ISL29003 ambient light sensor
	*
	* See file:Documentation/misc-devices/isl29003.rst
	*
	* Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
	*
	* Based on code written by
	* Rodolfo Giometti <giometti@linux.it>
	* Eurotech S.p.A. <info@eurotech.it>
	*/

	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/i2c.h>
	#include <linux/mutex.h>
	#include <linux/delay.h>

	#define ISL29003_DRV_NAME "isl29003"
	#define DRIVER_VERSION "1.0"

	#define ISL29003_REG_COMMAND 0x00
	#define ISL29003_ADC_ENABLED (1 << 7)
	#define ISL29003_ADC_PD (1 << 6)
	#define ISL29003_TIMING_INT (1 << 5)
	#define ISL29003_MODE_SHIFT (2)
	#define ISL29003_MODE_MASK (0x3 << ISL29003_MODE_SHIFT)
	#define ISL29003_RES_SHIFT (0)
	#define ISL29003_RES_MASK (0x3 << ISL29003_RES_SHIFT)

	#define ISL29003_REG_CONTROL 0x01
	#define ISL29003_INT_FLG (1 << 5)
	#define ISL29003_RANGE_SHIFT (2)
	#define ISL29003_RANGE_MASK (0x3 << ISL29003_RANGE_SHIFT)
	#define ISL29003_INT_PERSISTS_SHIFT (0)
	#define ISL29003_INT_PERSISTS_MASK (0xf << ISL29003_INT_PERSISTS_SHIFT)

	#define ISL29003_REG_IRQ_THRESH_HI 0x02
	#define ISL29003_REG_IRQ_THRESH_LO 0x03
	#define ISL29003_REG_LSB_SENSOR 0x04
	#define ISL29003_REG_MSB_SENSOR 0x05
	#define ISL29003_REG_LSB_TIMER 0x06
	#define ISL29003_REG_MSB_TIMER 0x07

	#define ISL29003_NUM_CACHABLE_REGS 4

	struct isl29003_data {
	struct i2c_client *client;
	struct mutex lock;
	u8 reg_cache[ISL29003_NUM_CACHABLE_REGS];
	u8 power_state_before_suspend;
	};

	static int gain_range[] = {
	1000, 4000, 16000, 64000
	};

	/*
	* register access helpers
	*/

	static int __isl29003_read_reg(struct i2c_client *client,
	u32 reg, u8 mask, u8 shift)
	{
	struct isl29003_data *data = i2c_get_clientdata(client);

	return (data->reg_cache[reg] & mask) >> shift;
	}

	static int __isl29003_write_reg(struct i2c_client *client,
	u32 reg, u8 mask, u8 shift, u8 val)
	{
	struct isl29003_data *data = i2c_get_clientdata(client);
	int ret = 0;
	u8 tmp;

	if (reg >= ISL29003_NUM_CACHABLE_REGS)
	return -EINVAL;

	mutex_lock(&data->lock);

	tmp = data->reg_cache[reg];
	tmp &= ~mask;
	tmp \|= val << shift;

	ret = i2c_smbus_write_byte_data(client, reg, tmp);
	if (!ret)
	data->reg_cache[reg] = tmp;

	mutex_unlock(&data->lock);
	return ret;
	}

	/*
	* internally used functions
	*/

	/* range */
	static int isl29003_get_range(struct i2c_client *client)
	{
	return __isl29003_read_reg(client, ISL29003_REG_CONTROL,
	ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT);
	}

	static int isl29003_set_range(struct i2c_client *client, int range)
	{
	return __isl29003_write_reg(client, ISL29003_REG_CONTROL,
	ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT, range);
	}

	/* resolution */
	static int isl29003_get_resolution(struct i2c_client *client)
	{
	return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
	ISL29003_RES_MASK, ISL29003_RES_SHIFT);
	}

	static int isl29003_set_resolution(struct i2c_client *client, int res)
	{
	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
	ISL29003_RES_MASK, ISL29003_RES_SHIFT, res);
	}

	/* mode */
	static int isl29003_get_mode(struct i2c_client *client)
	{
	return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
	ISL29003_MODE_MASK, ISL29003_MODE_SHIFT);
	}

	static int isl29003_set_mode(struct i2c_client *client, int mode)
	{
	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
	ISL29003_MODE_MASK, ISL29003_MODE_SHIFT, mode);
	}

	/* power_state */
	static int isl29003_set_power_state(struct i2c_client *client, int state)
	{
	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
	ISL29003_ADC_ENABLED \| ISL29003_ADC_PD, 0,
	state ? ISL29003_ADC_ENABLED : ISL29003_ADC_PD);
	}

	static int isl29003_get_power_state(struct i2c_client *client)
	{
	struct isl29003_data *data = i2c_get_clientdata(client);
	u8 cmdreg = data->reg_cache[ISL29003_REG_COMMAND];

	return ~cmdreg & ISL29003_ADC_PD;
	}

	static int isl29003_get_adc_value(struct i2c_client *client)
	{
	struct isl29003_data *data = i2c_get_clientdata(client);
	int lsb, msb, range, bitdepth;

	mutex_lock(&data->lock);
	lsb = i2c_smbus_read_byte_data(client, ISL29003_REG_LSB_SENSOR);

	if (lsb < 0) {
	mutex_unlock(&data->lock);
	return lsb;
	}

	msb = i2c_smbus_read_byte_data(client, ISL29003_REG_MSB_SENSOR);
	mutex_unlock(&data->lock);

	if (msb < 0)
	return msb;

	range = isl29003_get_range(client);
	bitdepth = (4 - isl29003_get_resolution(client)) * 4;
	return (((msb << 8) \| lsb) * gain_range[range]) >> bitdepth;
	}

	/*
	* sysfs layer
	*/

	/* range */
	static ssize_t isl29003_show_range(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct i2c_client *client = to_i2c_client(dev);

	return sprintf(buf, "%i\n", isl29003_get_range(client));
	}

	static ssize_t isl29003_store_range(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long val;
	int ret;

	ret = kstrtoul(buf, 10, &val);
	if (ret)
	return ret;

	if (val > 3)
	return -EINVAL;

	ret = isl29003_set_range(client, val);
	if (ret < 0)
	return ret;

	return count;
	}

	static DEVICE_ATTR(range, S_IWUSR \| S_IRUGO,
	isl29003_show_range, isl29003_store_range);


	/* resolution */
	static ssize_t isl29003_show_resolution(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct i2c_client *client = to_i2c_client(dev);

	return sprintf(buf, "%d\n", isl29003_get_resolution(client));
	}

	static ssize_t isl29003_store_resolution(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long val;
	int ret;

	ret = kstrtoul(buf, 10, &val);
	if (ret)
	return ret;

	if (val > 3)
	return -EINVAL;

	ret = isl29003_set_resolution(client, val);
	if (ret < 0)
	return ret;

	return count;
	}

	static DEVICE_ATTR(resolution, S_IWUSR \| S_IRUGO,
	isl29003_show_resolution, isl29003_store_resolution);

	/* mode */
	static ssize_t isl29003_show_mode(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct i2c_client *client = to_i2c_client(dev);

	return sprintf(buf, "%d\n", isl29003_get_mode(client));
	}

	static ssize_t isl29003_store_mode(struct device *dev,
	struct device_attribute attr, const char buf, size_t count)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long val;
	int ret;

	ret = kstrtoul(buf, 10, &val);
	if (ret)
	return ret;

	if (val > 2)
	return -EINVAL;

	ret = isl29003_set_mode(client, val);
	if (ret < 0)
	return ret;

	return count;
	}

	static DEVICE_ATTR(mode, S_IWUSR \| S_IRUGO,
	isl29003_show_mode, isl29003_store_mode);


	/* power state */
	static ssize_t isl29003_show_power_state(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct i2c_client *client = to_i2c_client(dev);

	return sprintf(buf, "%d\n", isl29003_get_power_state(client));
	}

	static ssize_t isl29003_store_power_state(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long val;
	int ret;

	ret = kstrtoul(buf, 10, &val);
	if (ret)
	return ret;

	if (val > 1)
	return -EINVAL;

	ret = isl29003_set_power_state(client, val);
	return ret ? ret : count;
	}

	static DEVICE_ATTR(power_state, S_IWUSR \| S_IRUGO,
	isl29003_show_power_state, isl29003_store_power_state);


	/* lux */
	static ssize_t isl29003_show_lux(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct i2c_client *client = to_i2c_client(dev);

	/* No LUX data if not operational */
	if (!isl29003_get_power_state(client))
	return -EBUSY;

	return sprintf(buf, "%d\n", isl29003_get_adc_value(client));
	}

	static DEVICE_ATTR(lux, S_IRUGO, isl29003_show_lux, NULL);

	static struct attribute *isl29003_attributes[] = {
	&dev_attr_range.attr,
	&dev_attr_resolution.attr,
	&dev_attr_mode.attr,
	&dev_attr_power_state.attr,
	&dev_attr_lux.attr,
	NULL
	};

	static const struct attribute_group isl29003_attr_group = {
	.attrs = isl29003_attributes,
	};

	static int isl29003_init_client(struct i2c_client *client)
	{
	struct isl29003_data *data = i2c_get_clientdata(client);
	int i;

	/* read all the registers once to fill the cache.
	* if one of the reads fails, we consider the init failed */
	for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++) {
	int v = i2c_smbus_read_byte_data(client, i);

	if (v < 0)
	return -ENODEV;

	data->reg_cache[i] = v;
	}

	/* set defaults */
	isl29003_set_range(client, 0);
	isl29003_set_resolution(client, 0);
	isl29003_set_mode(client, 0);
	isl29003_set_power_state(client, 0);

	return 0;
	}

	/*
	* I2C layer
	*/

	static int isl29003_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adapter = client->adapter;
	struct isl29003_data *data;
	int err = 0;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
	return -EIO;

	data = kzalloc(sizeof(struct isl29003_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->client = client;
	i2c_set_clientdata(client, data);
	mutex_init(&data->lock);

	/* initialize the ISL29003 chip */
	err = isl29003_init_client(client);
	if (err)
	goto exit_kfree;

	/* register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &isl29003_attr_group);
	if (err)
	goto exit_kfree;

	dev_info(&client->dev, "driver version %s enabled\n", DRIVER_VERSION);
	return 0;

	exit_kfree:
	kfree(data);
	return err;
	}

	static int isl29003_remove(struct i2c_client *client)
	{
	sysfs_remove_group(&client->dev.kobj, &isl29003_attr_group);
	isl29003_set_power_state(client, 0);
	kfree(i2c_get_clientdata(client));
	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int isl29003_suspend(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct isl29003_data *data = i2c_get_clientdata(client);

	data->power_state_before_suspend = isl29003_get_power_state(client);
	return isl29003_set_power_state(client, 0);
	}

	static int isl29003_resume(struct device *dev)
	{
	int i;
	struct i2c_client *client = to_i2c_client(dev);
	struct isl29003_data *data = i2c_get_clientdata(client);

	/* restore registers from cache */
	for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++)
	if (i2c_smbus_write_byte_data(client, i, data->reg_cache[i]))
	return -EIO;

	return isl29003_set_power_state(client,
	data->power_state_before_suspend);
	}

	static SIMPLE_DEV_PM_OPS(isl29003_pm_ops, isl29003_suspend, isl29003_resume);
	#define ISL29003_PM_OPS (&isl29003_pm_ops)

	#else
	#define ISL29003_PM_OPS NULL
	#endif /* CONFIG_PM_SLEEP */

	static const struct i2c_device_id isl29003_id[] = {
	{ "isl29003", 0 },
	{}
	};
	MODULE_DEVICE_TABLE(i2c, isl29003_id);

	static struct i2c_driver isl29003_driver = {
	.driver = {
	.name = ISL29003_DRV_NAME,
	.pm = ISL29003_PM_OPS,
	},
	.probe = isl29003_probe,
	.remove = isl29003_remove,
	.id_table = isl29003_id,
	};

	module_i2c_driver(isl29003_driver);

	MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
	MODULE_DESCRIPTION("ISL29003 ambient light sensor driver");
	MODULE_LICENSE("GPL v2");
	MODULE_VERSION(DRIVER_VERSION);