/*
 * Copyright (C) 2011-2014 Freescale Semiconductor, Inc. All Rights Reserved.
 */

/*
 * 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.

 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/isl29023.h>

#define ISL29023_DRV_NAME		"isl29023"
#define DRIVER_VERSION			"1.0"

#define ISL29023_COMMAND1		(0x00)
#define ISL29023_MODE_SHIFT		(5)
#define ISL29023_MODE_MASK		(0x7 << ISL29023_MODE_SHIFT)
#define ISL29023_INT_FLAG_SHIFT		(2)
#define ISL29023_INT_FLAG_MASK		(0x1 << ISL29023_INT_FLAG_SHIFT)
#define ISL29023_INT_PERSISTS_SHIFT	(0)
#define ISL29023_INT_PERSISTS_MASK	(0x3 << ISL29023_INT_PERSISTS_SHIFT)

#define ISL29023_COMMAND2		(0x01)
#define ISL29023_RES_SHIFT		(2)
#define ISL29023_RES_MASK		(0x3 << ISL29023_RES_SHIFT)
#define ISL29023_RANGE_SHIFT		(0)
#define ISL29023_RANGE_MASK		(0x3 << ISL29023_RANGE_SHIFT)

#define ISL29023_REG_LSB_SENSOR		(0x02)
#define ISL29023_REG_MSB_SENSOR		(0x03)
#define ISL29023_REG_IRQ_TH_LO_LSB	(0x04)
#define ISL29023_REG_IRQ_TH_LO_MSB	(0x05)
#define ISL29023_REG_IRQ_TH_HI_LSB	(0x06)
#define ISL29023_REG_IRQ_TH_HI_MSB	(0x07)

#define ISL29023_NUM_CACHABLE_REGS	8
#define DEF_RANGE			2
#define DEFAULT_REGISTOR_VAL		499

struct isl29023_data {
	struct i2c_client *client;
	struct mutex lock;
	struct input_dev *input;
	struct work_struct work;
	struct workqueue_struct *workqueue;
	char phys[32];
	u8 reg_cache[ISL29023_NUM_CACHABLE_REGS];
	u8 mode_before_suspend;
	u8 mode_before_interrupt;
	u16 rext;
};

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

/*
 * register access helpers
 */
static int __isl29023_read_reg(struct i2c_client *client,
			       u32 reg, u8 mask, u8 shift)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	return (data->reg_cache[reg] & mask) >> shift;
}

static int __isl29023_write_reg(struct i2c_client *client,
				u32 reg, u8 mask, u8 shift, u8 val)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	int ret = 0;
	u8 tmp;

	if (reg >= ISL29023_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
 */
static int isl29023_get_int_persists(struct i2c_client *client)
{
	return __isl29023_read_reg(client, ISL29023_COMMAND1,
		ISL29023_INT_PERSISTS_MASK, ISL29023_INT_PERSISTS_SHIFT);
}

static int isl29023_set_int_persists(struct i2c_client *client,
				int int_persists)
{
	return __isl29023_write_reg(client, ISL29023_COMMAND1,
		ISL29023_INT_PERSISTS_MASK, ISL29023_INT_PERSISTS_SHIFT,
		int_persists);
}

/*
 * interrupt flag
 */
static int isl29023_get_int_flag(struct i2c_client *client)
{
	return __isl29023_read_reg(client, ISL29023_COMMAND1,
		ISL29023_INT_FLAG_MASK, ISL29023_INT_FLAG_SHIFT);
}

static int isl29023_set_int_flag(struct i2c_client *client, int flag)
{
	return __isl29023_write_reg(client, ISL29023_COMMAND1,
		ISL29023_INT_FLAG_MASK, ISL29023_INT_FLAG_SHIFT, flag);
}

/*
 * interrupt lt
 */
static int isl29023_get_int_lt(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	int lsb, msb, lt;

	mutex_lock(&data->lock);
	lsb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_LO_LSB);

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

	msb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_LO_MSB);
	mutex_unlock(&data->lock);

	if (msb < 0)
		return msb;

	lt = ((msb << 8) | lsb);

	return lt;
}

static int isl29023_set_int_lt(struct i2c_client *client, int lt)
{
	int ret = 0;
	struct isl29023_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->lock);
	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_LO_LSB,
					lt & 0xff);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_LO_MSB,
					(lt >> 8) & 0xff);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	data->reg_cache[ISL29023_REG_IRQ_TH_LO_MSB] = (lt >> 8) & 0xff;
	data->reg_cache[ISL29023_REG_IRQ_TH_LO_LSB] = lt & 0xff;
	mutex_unlock(&data->lock);

	return ret;
}

/*
 * interrupt ht
 */
static int isl29023_get_int_ht(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	int lsb, msb, ht;

	mutex_lock(&data->lock);
	lsb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_HI_LSB);

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

	msb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_HI_MSB);
	mutex_unlock(&data->lock);

	if (msb < 0)
		return msb;

	ht = ((msb << 8) | lsb);

	return ht;
}

static int isl29023_set_int_ht(struct i2c_client *client, int ht)
{
	int ret = 0;
	struct isl29023_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->lock);
	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_HI_LSB,
					ht & 0xff);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_HI_MSB,
					(ht >> 8) & 0xff);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	data->reg_cache[ISL29023_REG_IRQ_TH_HI_MSB] = (ht >> 8) & 0xff;
	data->reg_cache[ISL29023_REG_IRQ_TH_HI_LSB] = ht & 0xff;
	mutex_unlock(&data->lock);

	return ret;
}

/*
 * range
 */
static int isl29023_get_range(struct i2c_client *client)
{
	return __isl29023_read_reg(client, ISL29023_COMMAND2,
		ISL29023_RANGE_MASK, ISL29023_RANGE_SHIFT);
}

static int isl29023_set_range(struct i2c_client *client, int range)
{
	return __isl29023_write_reg(client, ISL29023_COMMAND2,
		ISL29023_RANGE_MASK, ISL29023_RANGE_SHIFT, range);
}

/*
 * resolution
 */
static int isl29023_get_resolution(struct i2c_client *client)
{
	return __isl29023_read_reg(client, ISL29023_COMMAND2,
		ISL29023_RES_MASK, ISL29023_RES_SHIFT);
}

static int isl29023_set_resolution(struct i2c_client *client, int res)
{
	return __isl29023_write_reg(client, ISL29023_COMMAND2,
		ISL29023_RES_MASK, ISL29023_RES_SHIFT, res);
}

/*
 * mode
 */
static int isl29023_get_mode(struct i2c_client *client)
{
	return __isl29023_read_reg(client, ISL29023_COMMAND1,
		ISL29023_MODE_MASK, ISL29023_MODE_SHIFT);
}

static int isl29023_set_mode(struct i2c_client *client, int mode)
{
	return __isl29023_write_reg(client, ISL29023_COMMAND1,
		ISL29023_MODE_MASK, ISL29023_MODE_SHIFT, mode);
}

/*
 * power_state
 */
static int isl29023_set_power_state(struct i2c_client *client, int state)
{
	return __isl29023_write_reg(client, ISL29023_COMMAND1,
				ISL29023_MODE_MASK, ISL29023_MODE_SHIFT,
				state ?
				ISL29023_ALS_ONCE_MODE : ISL29023_PD_MODE);
}

static int isl29023_get_power_state(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	u8 cmdreg = data->reg_cache[ISL29023_COMMAND1];

	if (cmdreg & ISL29023_MODE_MASK)
		return 1;
	else
		return 0;
}

static int isl29023_get_adc_value(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	int lsb, msb, range, bitdepth;

	mutex_lock(&data->lock);
	lsb = i2c_smbus_read_byte_data(client, ISL29023_REG_LSB_SENSOR);

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

	msb = i2c_smbus_read_byte_data(client, ISL29023_REG_MSB_SENSOR);
	mutex_unlock(&data->lock);

	if (msb < 0)
		return msb;

	range = isl29023_get_range(client);
	bitdepth = (4 - isl29023_get_resolution(client)) * 4;
	return (((msb << 8) | lsb) * ((gain_range[range] * 499) / data->rext))
		>> bitdepth;
}

static int isl29023_get_int_lt_value(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	int lsb, msb, range, bitdepth;

	mutex_lock(&data->lock);
	lsb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_LO_LSB);

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

	msb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_LO_MSB);
	mutex_unlock(&data->lock);

	if (msb < 0)
		return msb;

	range = isl29023_get_range(client);
	bitdepth = (4 - isl29023_get_resolution(client)) * 4;
	return (((msb << 8) | lsb) * ((gain_range[range] * 499) / data->rext))
		>> bitdepth;
}

static int isl29023_get_int_ht_value(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);
	int lsb, msb, range, bitdepth;

	mutex_lock(&data->lock);
	lsb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_HI_LSB);

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

	msb = i2c_smbus_read_byte_data(client, ISL29023_REG_IRQ_TH_HI_MSB);
	mutex_unlock(&data->lock);

	if (msb < 0)
		return msb;

	range = isl29023_get_range(client);
	bitdepth = (4 - isl29023_get_resolution(client)) * 4;
	return (((msb << 8) | lsb) * ((gain_range[range] * 499) / data->rext))
		>> bitdepth;
}

/*
 * sysfs layer
 */

/*
 * interrupt persists
 */
static ssize_t isl29023_show_int_persists(struct device *dev,
					  struct device_attribute *attr,
					  char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%i\n", isl29023_get_int_persists(client));
}

static ssize_t isl29023_store_int_persists(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;

	if ((kstrtoul(buf, 10, &val) < 0) ||
	    (val > ISL29023_INT_PERSISTS_16))
		return -EINVAL;

	ret = isl29023_set_int_persists(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(int_persists, S_IWUSR | S_IRUGO,
		   isl29023_show_int_persists, isl29023_store_int_persists);

/*
 *interrupt flag
 */
static ssize_t isl29023_show_int_flag(struct device *dev,
					  struct device_attribute *attr,
					  char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%i\n", isl29023_get_int_flag(client));
}

static ssize_t isl29023_store_int_flag(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;

	if ((kstrtoul(buf, 10, &val) < 0) || (val > 1))
		return -EINVAL;

	ret = isl29023_set_int_flag(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(int_flag, S_IWUSR | S_IRUGO,
		   isl29023_show_int_flag, isl29023_store_int_flag);

/*
 * interrupt lt
 */
static ssize_t isl29023_show_int_lt(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%i\n", isl29023_get_int_lt(client));
}

static ssize_t isl29023_store_int_lt(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;

	if ((kstrtoul(buf, 16, &val) < 0) || (val > 0xffff))
		return -EINVAL;

	ret = isl29023_set_int_lt(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(int_lt, S_IWUSR | S_IRUGO,
		   isl29023_show_int_lt, isl29023_store_int_lt);

/*
 *interrupt ht
 */
static ssize_t isl29023_show_int_ht(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%i\n", isl29023_get_int_ht(client));
}

static ssize_t isl29023_store_int_ht(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;

	if ((kstrtoul(buf, 16, &val) < 0) || (val > 0xffff))
		return -EINVAL;

	ret = isl29023_set_int_ht(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(int_ht, S_IWUSR | S_IRUGO,
		   isl29023_show_int_ht, isl29023_store_int_ht);

/*
 * range
 */
static ssize_t isl29023_show_range(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%i\n", isl29023_get_range(client));
}

static ssize_t isl29023_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;

	if ((kstrtoul(buf, 10, &val) < 0) || (val > ISL29023_RANGE_64K))
		return -EINVAL;

	ret = isl29023_set_range(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(range, S_IWUSR | S_IRUGO,
		   isl29023_show_range, isl29023_store_range);


/*
 * resolution
 */
static ssize_t isl29023_show_resolution(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%d\n", isl29023_get_resolution(client));
}

static ssize_t isl29023_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;

	if ((kstrtoul(buf, 10, &val) < 0) || (val > ISL29023_RES_4))
		return -EINVAL;

	ret = isl29023_set_resolution(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(resolution, S_IWUSR | S_IRUGO,
		   isl29023_show_resolution, isl29023_store_resolution);

/*
 *mode
 */
static ssize_t isl29023_show_mode(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	return sprintf(buf, "%d\n", isl29023_get_mode(client));
}

static ssize_t isl29023_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;

	if ((kstrtoul(buf, 10, &val) < 0) ||
	    (val > ISL29023_IR_CONT_MODE))
		return -EINVAL;

	/* clear the interrupt flag */
	i2c_smbus_read_byte_data(client, ISL29023_COMMAND1);
	ret = isl29023_set_mode(client, val);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
		   isl29023_show_mode, isl29023_store_mode);


/*
 *power state
 */
static ssize_t isl29023_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", isl29023_get_power_state(client));
}

static ssize_t isl29023_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;

	if ((kstrtoul(buf, 10, &val) < 0) || (val > 1))
		return -EINVAL;

	ret = isl29023_set_power_state(client, val);
	return ret ? ret : count;
}

static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
		   isl29023_show_power_state, isl29023_store_power_state);

/*
 * lux
 */
static ssize_t isl29023_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 (!isl29023_get_power_state(client))
		return -EBUSY;

	return sprintf(buf, "%d\n", isl29023_get_adc_value(client));
}

static DEVICE_ATTR(lux, S_IRUGO, isl29023_show_lux, NULL);

/*
 * lux interrupt low threshold
 */
static ssize_t isl29023_show_int_lt_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 (isl29023_get_mode(client) != ISL29023_ALS_ONCE_MODE &&
	    isl29023_get_mode(client) != ISL29023_ALS_CONT_MODE)
		return -EIO;

	return sprintf(buf, "%d\n", isl29023_get_int_lt_value(client));
}

static ssize_t isl29023_store_int_lt_lux(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct isl29023_data *data = i2c_get_clientdata(client);
	unsigned long val, lux_data;
	int range, bitdepth, ret;
	u8 lsb, msb;

	if ((kstrtoul(buf, 10, &val) < 0))
		return -EINVAL;

	/* No LUX data if not operational */
	if (isl29023_get_mode(client) != ISL29023_ALS_ONCE_MODE &&
	    isl29023_get_mode(client) != ISL29023_ALS_CONT_MODE)
		return -EIO;

	if (val > (gain_range[isl29023_get_range(client)]*499/data->rext))
		return -EINVAL;

	range = isl29023_get_range(client);
	bitdepth = (4 - isl29023_get_resolution(client)) * 4;
	lux_data = ((unsigned long)(val << bitdepth)) /
		((gain_range[range] * 499) / data->rext);
	lux_data &= 0xffff;

	msb = lux_data >> 8;
	lsb = lux_data & 0xff;

	mutex_lock(&data->lock);
	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_LO_LSB,
					lsb);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_LO_MSB,
					msb);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	data->reg_cache[ISL29023_REG_IRQ_TH_LO_MSB] = msb;
	data->reg_cache[ISL29023_REG_IRQ_TH_LO_LSB] = lsb;
	mutex_unlock(&data->lock);

	return count;
}

static DEVICE_ATTR(int_lt_lux, S_IWUSR | S_IRUGO,
		isl29023_show_int_lt_lux, isl29023_store_int_lt_lux);

/*
 * lux interrupt high threshold
 */
static ssize_t isl29023_show_int_ht_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 (isl29023_get_mode(client) != ISL29023_ALS_ONCE_MODE &&
	    isl29023_get_mode(client) != ISL29023_ALS_CONT_MODE)
		return -EIO;

	return sprintf(buf, "%d\n", isl29023_get_int_ht_value(client));
}

static ssize_t isl29023_store_int_ht_lux(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct isl29023_data *data = i2c_get_clientdata(client);
	unsigned long val, lux_data;
	int range, bitdepth, ret;
	u8 lsb, msb;

	if ((kstrtoul(buf, 10, &val) < 0))
		return -EINVAL;

	/* No LUX data if not operational */
	if (isl29023_get_mode(client) != ISL29023_ALS_ONCE_MODE &&
	    isl29023_get_mode(client) != ISL29023_ALS_CONT_MODE)
		return -EIO;

	if (val > (gain_range[isl29023_get_range(client)]*499/data->rext))
		return -EINVAL;

	range = isl29023_get_range(client);
	bitdepth = (4 - isl29023_get_resolution(client)) * 4;
	lux_data = ((unsigned long)(val << bitdepth)) /
		((gain_range[range] * 499) / data->rext);
	lux_data &= 0xffff;

	msb = lux_data >> 8;
	lsb = lux_data & 0xff;

	mutex_lock(&data->lock);
	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_HI_LSB,
					lsb);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	ret = i2c_smbus_write_byte_data(client, ISL29023_REG_IRQ_TH_HI_MSB,
					msb);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}

	data->reg_cache[ISL29023_REG_IRQ_TH_HI_MSB] = msb;
	data->reg_cache[ISL29023_REG_IRQ_TH_HI_LSB] = lsb;
	mutex_unlock(&data->lock);

	return count;
}

static DEVICE_ATTR(int_ht_lux, S_IWUSR | S_IRUGO,
		isl29023_show_int_ht_lux, isl29023_store_int_ht_lux);

static struct attribute *isl29023_attributes[] = {
	&dev_attr_int_persists.attr,
	&dev_attr_range.attr,
	&dev_attr_resolution.attr,
	&dev_attr_mode.attr,
	&dev_attr_power_state.attr,
	&dev_attr_lux.attr,
	&dev_attr_int_lt_lux.attr,
	&dev_attr_int_ht_lux.attr,
	&dev_attr_int_lt.attr,
	&dev_attr_int_ht.attr,
	&dev_attr_int_flag.attr,
	NULL
};

static const struct attribute_group isl29023_attr_group = {
	.attrs = isl29023_attributes,
};

static int isl29023_init_client(struct i2c_client *client)
{
	struct isl29023_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 */
	isl29023_set_int_persists(client, ISL29023_INT_PERSISTS_8);
	isl29023_set_int_ht(client, 0xffff);
	isl29023_set_int_lt(client, 0x0);
	isl29023_set_range(client, ISL29023_RANGE_16K);
	isl29023_set_resolution(client, ISL29023_RES_16);
	isl29023_set_mode(client, ISL29023_ALS_ONCE_MODE);
	isl29023_set_int_flag(client, 0);
	isl29023_set_power_state(client, 0);

	return 0;
}

static void isl29023_work(struct work_struct *work)
{
	struct isl29023_data *data =
			container_of(work, struct isl29023_data, work);
	struct i2c_client *client = data->client;
	int lux;

	/* Clear interrupt flag */
	isl29023_set_int_flag(client, 0);

	data->mode_before_interrupt = isl29023_get_mode(client);
	lux = isl29023_get_adc_value(client);

	/* To clear the interrpt status */
	isl29023_set_power_state(client, ISL29023_PD_MODE);
	isl29023_set_mode(client, data->mode_before_interrupt);

	msleep(100);

	input_report_abs(data->input, ABS_MISC, lux);
	input_sync(data->input);
}

static irqreturn_t isl29023_irq_handler(int irq, void *handle)
{
	struct isl29023_data *data = handle;
	int cmd_1;
	cmd_1 = i2c_smbus_read_byte_data(data->client, ISL29023_COMMAND1);
	if (!(cmd_1 & ISL29023_INT_FLAG_MASK))
		return IRQ_NONE;

	queue_work(data->workqueue, &data->work);
	return IRQ_HANDLED;
}

/*
 * I2C layer
 */
static int isl29023_probe(struct i2c_client *client,
				    const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
	struct isl29023_data *data;
	struct input_dev *input_dev;
	int err = 0;
	struct regulator *vdd = NULL;
	u32 rext = 0;
	struct device_node *of_node = client->dev.of_node;
	struct irq_data *irq_data = irq_get_irq_data(client->irq);
	u32 irq_flag;
	bool shared_irq;

	vdd = devm_regulator_get(&client->dev, "vdd");
	if (!IS_ERR(vdd)) {
		err  = regulator_enable(vdd);
		if (err) {
			dev_err(&client->dev, "vdd set voltage error\n");
			return err;
		}
	}

	err = of_property_read_u32(of_node, "rext", &rext);
	if (err || rext == 0)
		rext = DEFAULT_REGISTOR_VAL;
	shared_irq = of_property_read_bool(of_node, "shared-interrupt");

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

	data = kzalloc(sizeof(struct isl29023_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->client = client;
	data->rext = (u16)rext;
	snprintf(data->phys, sizeof(data->phys),
		 "%s", dev_name(&client->dev));
	i2c_set_clientdata(client, data);
	mutex_init(&data->lock);

	/* initialize the ISL29023 chip */
	err = isl29023_init_client(client);
	if (err)
		goto exit_kfree;

	/* register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &isl29023_attr_group);
	if (err)
		goto exit_kfree;

	input_dev = input_allocate_device();
	if (!input_dev) {
		err = -ENOMEM;
		goto exit_kfree;
	}

	data->input = input_dev;
	input_dev->name = "isl29023 light sensor";
	input_dev->id.bustype = BUS_I2C;
	input_dev->phys = data->phys;

	__set_bit(EV_ABS, input_dev->evbit);
	input_set_abs_params(input_dev, ABS_MISC, 0,
			gain_range[DEF_RANGE]*499/data->rext, 0, 0);

	err = input_register_device(input_dev);
	if (err)
		goto exit_free_input;

	irq_flag = irqd_get_trigger_type(irq_data);
	irq_flag |= IRQF_ONESHOT;
	if (shared_irq)
		irq_flag |= IRQF_SHARED;
	err = request_threaded_irq(client->irq, NULL,
					isl29023_irq_handler, irq_flag,
					client->dev.driver->name, data);
	if (err < 0) {
		dev_err(&client->dev, "failed to register irq %d!\n",
			client->irq);
		goto exit_free_input;
	}

	data->workqueue = create_singlethread_workqueue("isl29023");
	INIT_WORK(&data->work, isl29023_work);
	if (data->workqueue == NULL) {
		dev_err(&client->dev, "couldn't create workqueue\n");
		err = -ENOMEM;
		goto exit_free_interrupt;
	}

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

exit_free_interrupt:
	free_irq(client->irq, data);
exit_free_input:
	input_free_device(input_dev);
exit_kfree:
	kfree(data);
	return err;
}

static int isl29023_remove(struct i2c_client *client)
{
	struct isl29023_data *data = i2c_get_clientdata(client);

	cancel_work_sync(&data->work);
	destroy_workqueue(data->workqueue);
	free_irq(client->irq, data);
	input_unregister_device(data->input);
	input_free_device(data->input);
	sysfs_remove_group(&client->dev.kobj, &isl29023_attr_group);
	isl29023_set_power_state(client, 0);
	kfree(i2c_get_clientdata(client));

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int isl29023_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct isl29023_data *data = i2c_get_clientdata(client);

	data->mode_before_suspend = isl29023_get_mode(client);
	return isl29023_set_power_state(client, ISL29023_PD_MODE);
}

static int isl29023_resume(struct device *dev)
{
	int i;
	struct i2c_client *client = to_i2c_client(dev);
	struct isl29023_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 isl29023_set_mode(client, data->mode_before_suspend);
}
#endif

static SIMPLE_DEV_PM_OPS(isl29023_pm_ops, isl29023_suspend, isl29023_resume);

static const struct i2c_device_id isl29023_id[] = {
	{ ISL29023_DRV_NAME, 0 },
	{}
};
MODULE_DEVICE_TABLE(i2c, isl29023_id);

static struct i2c_driver isl29023_driver = {
	.driver = {
		.name	= ISL29023_DRV_NAME,
		.owner	= THIS_MODULE,
		.pm	= &isl29023_pm_ops,
	},
	.probe	= isl29023_probe,
	.remove	= isl29023_remove,
	.id_table = isl29023_id,
};

static int __init isl29023_init(void)
{
	return i2c_add_driver(&isl29023_driver);
}

static void __exit isl29023_exit(void)
{
	i2c_del_driver(&isl29023_driver);
}

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("ISL29023 ambient light sensor driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRIVER_VERSION);

module_init(isl29023_init);
module_exit(isl29023_exit);