linux-next/drivers/iio/light/ltr501.c

/*
 * ltr501.c - Support for Lite-On LTR501 ambient light and proximity sensor
 *
 * Copyright 2014 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * 7-bit I2C slave address 0x23
 *
 * TODO: IR LED characteristics
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/regmap.h>
#include <linux/acpi.h>

#include <linux/iio/iio.h>
#include <linux/iio/events.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>

#define LTR501_DRV_NAME "ltr501"

#define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
#define LTR501_PS_CONTR 0x81 /* PS operation mode */
#define LTR501_PS_MEAS_RATE 0x84 /* measurement rate*/
#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
#define LTR501_PART_ID 0x86
#define LTR501_MANUFAC_ID 0x87
#define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
#define LTR501_ALS_DATA0 0x8a /* 16-bit, little endian */
#define LTR501_ALS_PS_STATUS 0x8c
#define LTR501_PS_DATA 0x8d /* 16-bit, little endian */
#define LTR501_INTR 0x8f /* output mode, polarity, mode */
#define LTR501_PS_THRESH_UP 0x90 /* 11 bit, ps upper threshold */
#define LTR501_PS_THRESH_LOW 0x92 /* 11 bit, ps lower threshold */
#define LTR501_ALS_THRESH_UP 0x97 /* 16 bit, ALS upper threshold */
#define LTR501_ALS_THRESH_LOW 0x99 /* 16 bit, ALS lower threshold */
#define LTR501_INTR_PRST 0x9e /* ps thresh, als thresh */
#define LTR501_MAX_REG 0x9f

#define LTR501_ALS_CONTR_SW_RESET BIT(2)
#define LTR501_CONTR_PS_GAIN_MASK (BIT(3) | BIT(2))
#define LTR501_CONTR_PS_GAIN_SHIFT 2
#define LTR501_CONTR_ALS_GAIN_MASK BIT(3)
#define LTR501_CONTR_ACTIVE BIT(1)

#define LTR501_STATUS_ALS_INTR BIT(3)
#define LTR501_STATUS_ALS_RDY BIT(2)
#define LTR501_STATUS_PS_INTR BIT(1)
#define LTR501_STATUS_PS_RDY BIT(0)

#define LTR501_PS_DATA_MASK 0x7ff
#define LTR501_PS_THRESH_MASK 0x7ff
#define LTR501_ALS_THRESH_MASK 0xffff

#define LTR501_ALS_DEF_PERIOD 500000
#define LTR501_PS_DEF_PERIOD 100000

#define LTR501_REGMAP_NAME "ltr501_regmap"

static const int int_time_mapping[] = {100000, 50000, 200000, 400000};

static const struct reg_field reg_field_it =
				REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
static const struct reg_field reg_field_als_intr =
				REG_FIELD(LTR501_INTR, 0, 0);
static const struct reg_field reg_field_ps_intr =
				REG_FIELD(LTR501_INTR, 1, 1);
static const struct reg_field reg_field_als_rate =
				REG_FIELD(LTR501_ALS_MEAS_RATE, 0, 2);
static const struct reg_field reg_field_ps_rate =
				REG_FIELD(LTR501_PS_MEAS_RATE, 0, 3);
static const struct reg_field reg_field_als_prst =
				REG_FIELD(LTR501_INTR_PRST, 0, 3);
static const struct reg_field reg_field_ps_prst =
				REG_FIELD(LTR501_INTR_PRST, 4, 7);

struct ltr501_samp_table {
	int freq_val;  /* repetition frequency in micro HZ*/
	int time_val; /* repetition rate in micro seconds */
};

struct ltr501_data {
	struct i2c_client *client;
	struct mutex lock_als, lock_ps;
	u8 als_contr, ps_contr;
	int als_period, ps_period; /* period in micro seconds */
	struct regmap *regmap;
	struct regmap_field *reg_it;
	struct regmap_field *reg_als_intr;
	struct regmap_field *reg_ps_intr;
	struct regmap_field *reg_als_rate;
	struct regmap_field *reg_ps_rate;
	struct regmap_field *reg_als_prst;
	struct regmap_field *reg_ps_prst;
};

static const struct ltr501_samp_table ltr501_als_samp_table[] = {
			{20000000, 50000}, {10000000, 100000},
			{5000000, 200000}, {2000000, 500000},
			{1000000, 1000000}, {500000, 2000000},
			{500000, 2000000}, {500000, 2000000}
};

static const struct ltr501_samp_table ltr501_ps_samp_table[] = {
			{20000000, 50000}, {14285714, 70000},
			{10000000, 100000}, {5000000, 200000},
			{2000000, 500000}, {1000000, 1000000},
			{500000, 2000000}, {500000, 2000000},
			{500000, 2000000}
};

static unsigned int ltr501_match_samp_freq(const struct ltr501_samp_table *tab,
					   int len, int val, int val2)
{
	int i, freq;

	freq = val * 1000000 + val2;

	for (i = 0; i < len; i++) {
		if (tab[i].freq_val == freq)
			return i;
	}

	return -EINVAL;
}

static int ltr501_als_read_samp_freq(struct ltr501_data *data,
				     int *val, int *val2)
{
	int ret, i;

	ret = regmap_field_read(data->reg_als_rate, &i);
	if (ret < 0)
		return ret;

	if (i < 0 || i >= ARRAY_SIZE(ltr501_als_samp_table))
		return -EINVAL;

	*val = ltr501_als_samp_table[i].freq_val / 1000000;
	*val2 = ltr501_als_samp_table[i].freq_val % 1000000;

	return IIO_VAL_INT_PLUS_MICRO;
}

static int ltr501_ps_read_samp_freq(struct ltr501_data *data,
				    int *val, int *val2)
{
	int ret, i;

	ret = regmap_field_read(data->reg_ps_rate, &i);
	if (ret < 0)
		return ret;

	if (i < 0 || i >= ARRAY_SIZE(ltr501_ps_samp_table))
		return -EINVAL;

	*val = ltr501_ps_samp_table[i].freq_val / 1000000;
	*val2 = ltr501_ps_samp_table[i].freq_val % 1000000;

	return IIO_VAL_INT_PLUS_MICRO;
}

static int ltr501_als_write_samp_freq(struct ltr501_data *data,
				      int val, int val2)
{
	int i, ret;

	i = ltr501_match_samp_freq(ltr501_als_samp_table,
				   ARRAY_SIZE(ltr501_als_samp_table),
				   val, val2);

	if (i < 0)
		return i;

	mutex_lock(&data->lock_als);
	ret = regmap_field_write(data->reg_als_rate, i);
	mutex_unlock(&data->lock_als);

	return ret;
}

static int ltr501_ps_write_samp_freq(struct ltr501_data *data,
				     int val, int val2)
{
	int i, ret;

	i = ltr501_match_samp_freq(ltr501_ps_samp_table,
				   ARRAY_SIZE(ltr501_ps_samp_table),
				   val, val2);

	if (i < 0)
		return i;

	mutex_lock(&data->lock_ps);
	ret = regmap_field_write(data->reg_ps_rate, i);
	mutex_unlock(&data->lock_ps);

	return ret;
}

static int ltr501_als_read_samp_period(struct ltr501_data *data, int *val)
{
	int ret, i;

	ret = regmap_field_read(data->reg_als_rate, &i);
	if (ret < 0)
		return ret;

	if (i < 0 || i >= ARRAY_SIZE(ltr501_als_samp_table))
		return -EINVAL;

	*val = ltr501_als_samp_table[i].time_val;

	return IIO_VAL_INT;
}

static int ltr501_ps_read_samp_period(struct ltr501_data *data, int *val)
{
	int ret, i;

	ret = regmap_field_read(data->reg_ps_rate, &i);
	if (ret < 0)
		return ret;

	if (i < 0 || i >= ARRAY_SIZE(ltr501_ps_samp_table))
		return -EINVAL;

	*val = ltr501_ps_samp_table[i].time_val;

	return IIO_VAL_INT;
}

static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
{
	int tries = 100;
	int ret, status;

	while (tries--) {
		ret = regmap_read(data->regmap, LTR501_ALS_PS_STATUS, &status);
		if (ret < 0)
			return ret;
		if ((status & drdy_mask) == drdy_mask)
			return 0;
		msleep(25);
	}

	dev_err(&data->client->dev, "ltr501_drdy() failed, data not ready\n");
	return -EIO;
}

static int ltr501_set_it_time(struct ltr501_data *data, int it)
{
	int ret, i, index = -1, status;

	for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
		if (int_time_mapping[i] == it) {
			index = i;
			break;
		}
	}
	/* Make sure integ time index is valid */
	if (index < 0)
		return -EINVAL;

	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
	if (ret < 0)
		return ret;

	if (status & LTR501_CONTR_ALS_GAIN_MASK) {
		/*
		 * 200 ms and 400 ms integ time can only be
		 * used in dynamic range 1
		 */
		if (index > 1)
			return -EINVAL;
	} else
		/* 50 ms integ time can only be used in dynamic range 2 */
		if (index == 1)
			return -EINVAL;

	return regmap_field_write(data->reg_it, index);
}

/* read int time in micro seconds */
static int ltr501_read_it_time(struct ltr501_data *data, int *val, int *val2)
{
	int ret, index;

	ret = regmap_field_read(data->reg_it, &index);
	if (ret < 0)
		return ret;

	/* Make sure integ time index is valid */
	if (index < 0 || index >= ARRAY_SIZE(int_time_mapping))
		return -EINVAL;

	*val2 = int_time_mapping[index];
	*val = 0;

	return IIO_VAL_INT_PLUS_MICRO;
}

static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
{
	int ret;

	ret = ltr501_drdy(data, LTR501_STATUS_ALS_RDY);
	if (ret < 0)
		return ret;
	/* always read both ALS channels in given order */
	return regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
				buf, 2 * sizeof(__le16));
}

static int ltr501_read_ps(struct ltr501_data *data)
{
	int ret, status;

	ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
	if (ret < 0)
		return ret;

	ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
			       &status, 2);
	if (ret < 0)
		return ret;

	return status;
}

static int ltr501_read_intr_prst(struct ltr501_data *data,
				 enum iio_chan_type type,
				 int *val2)
{
	int ret, samp_period, prst;

	switch (type) {
	case IIO_INTENSITY:
		ret = regmap_field_read(data->reg_als_prst, &prst);
		if (ret < 0)
			return ret;

		ret = ltr501_als_read_samp_period(data, &samp_period);

		if (ret < 0)
			return ret;
		*val2 = samp_period * prst;
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_PROXIMITY:
		ret = regmap_field_read(data->reg_ps_prst, &prst);
		if (ret < 0)
			return ret;

		ret = ltr501_ps_read_samp_period(data, &samp_period);

		if (ret < 0)
			return ret;

		*val2 = samp_period * prst;
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static int ltr501_write_intr_prst(struct ltr501_data *data,
				  enum iio_chan_type type,
				  int val, int val2)
{
	int ret, samp_period, new_val;
	unsigned long period;

	if (val < 0 || val2 < 0)
		return -EINVAL;

	/* period in microseconds */
	period = ((val * 1000000) + val2);

	switch (type) {
	case IIO_INTENSITY:
		ret = ltr501_als_read_samp_period(data, &samp_period);
		if (ret < 0)
			return ret;

		/* period should be atleast equal to sampling period */
		if (period < samp_period)
			return -EINVAL;

		new_val = DIV_ROUND_UP(period, samp_period);
		if (new_val < 0 || new_val > 0x0f)
			return -EINVAL;

		mutex_lock(&data->lock_als);
		ret = regmap_field_write(data->reg_als_prst, new_val);
		mutex_unlock(&data->lock_als);
		if (ret >= 0)
			data->als_period = period;

		return ret;
	case IIO_PROXIMITY:
		ret = ltr501_ps_read_samp_period(data, &samp_period);
		if (ret < 0)
			return ret;

		/* period should be atleast equal to rate */
		if (period < samp_period)
			return -EINVAL;

		new_val = DIV_ROUND_UP(period, samp_period);
		if (new_val < 0 || new_val > 0x0f)
			return -EINVAL;

		mutex_lock(&data->lock_ps);
		ret = regmap_field_write(data->reg_ps_prst, new_val);
		mutex_unlock(&data->lock_ps);
		if (ret >= 0)
			data->ps_period = period;

		return ret;
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static const struct iio_event_spec ltr501_als_event_spec[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_EITHER,
		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
				 BIT(IIO_EV_INFO_PERIOD),
	},

};

static const struct iio_event_spec ltr501_pxs_event_spec[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_EITHER,
		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
				 BIT(IIO_EV_INFO_PERIOD),
	},
};

#define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared, \
				 _evspec, _evsize) { \
	.type = IIO_INTENSITY, \
	.modified = 1, \
	.address = (_addr), \
	.channel2 = (_mod), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = (_shared), \
	.scan_index = (_idx), \
	.scan_type = { \
		.sign = 'u', \
		.realbits = 16, \
		.storagebits = 16, \
		.endianness = IIO_CPU, \
	}, \
	.event_spec = _evspec,\
	.num_event_specs = _evsize,\
}

static const struct iio_chan_spec ltr501_channels[] = {
	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
				 ltr501_als_event_spec,
				 ARRAY_SIZE(ltr501_als_event_spec)),
	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
				 BIT(IIO_CHAN_INFO_SCALE) |
				 BIT(IIO_CHAN_INFO_INT_TIME) |
				 BIT(IIO_CHAN_INFO_SAMP_FREQ),
				 NULL, 0),
	{
		.type = IIO_PROXIMITY,
		.address = LTR501_PS_DATA,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
			BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 2,
		.scan_type = {
			.sign = 'u',
			.realbits = 11,
			.storagebits = 16,
			.endianness = IIO_CPU,
		},
		.event_spec = ltr501_pxs_event_spec,
		.num_event_specs = ARRAY_SIZE(ltr501_pxs_event_spec),
	},
	IIO_CHAN_SOFT_TIMESTAMP(3),
};

static const int ltr501_ps_gain[4][2] = {
	{1, 0}, {0, 250000}, {0, 125000}, {0, 62500}
};

static int ltr501_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct ltr501_data *data = iio_priv(indio_dev);
	__le16 buf[2];
	int ret, i;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (iio_buffer_enabled(indio_dev))
			return -EBUSY;

		switch (chan->type) {
		case IIO_INTENSITY:
			mutex_lock(&data->lock_als);
			ret = ltr501_read_als(data, buf);
			mutex_unlock(&data->lock_als);
			if (ret < 0)
				return ret;
			*val = le16_to_cpu(chan->address == LTR501_ALS_DATA1 ?
					   buf[0] : buf[1]);
			return IIO_VAL_INT;
		case IIO_PROXIMITY:
			mutex_lock(&data->lock_ps);
			ret = ltr501_read_ps(data);
			mutex_unlock(&data->lock_ps);
			if (ret < 0)
				return ret;
			*val = ret & LTR501_PS_DATA_MASK;
			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_SCALE:
		switch (chan->type) {
		case IIO_INTENSITY:
			if (data->als_contr & LTR501_CONTR_ALS_GAIN_MASK) {
				*val = 0;
				*val2 = 5000;
				return IIO_VAL_INT_PLUS_MICRO;
			}
			*val = 1;
			*val2 = 0;
			return IIO_VAL_INT;
		case IIO_PROXIMITY:
			i = (data->ps_contr & LTR501_CONTR_PS_GAIN_MASK) >>
				LTR501_CONTR_PS_GAIN_SHIFT;
			*val = ltr501_ps_gain[i][0];
			*val2 = ltr501_ps_gain[i][1];
			return IIO_VAL_INT_PLUS_MICRO;
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_INT_TIME:
		switch (chan->type) {
		case IIO_INTENSITY:
			return ltr501_read_it_time(data, val, val2);
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_SAMP_FREQ:
		switch (chan->type) {
		case IIO_INTENSITY:
			return ltr501_als_read_samp_freq(data, val, val2);
		case IIO_PROXIMITY:
			return ltr501_ps_read_samp_freq(data, val, val2);
		default:
			return -EINVAL;
		}
	}
	return -EINVAL;
}

static int ltr501_get_ps_gain_index(int val, int val2)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(ltr501_ps_gain); i++)
		if (val == ltr501_ps_gain[i][0] && val2 == ltr501_ps_gain[i][1])
			return i;

	return -1;
}

static int ltr501_write_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int val, int val2, long mask)
{
	struct ltr501_data *data = iio_priv(indio_dev);
	int i, ret, freq_val, freq_val2;

	if (iio_buffer_enabled(indio_dev))
		return -EBUSY;

	switch (mask) {
	case IIO_CHAN_INFO_SCALE:
		switch (chan->type) {
		case IIO_INTENSITY:
			if (val == 0 && val2 == 5000)
				data->als_contr |= LTR501_CONTR_ALS_GAIN_MASK;
			else if (val == 1 && val2 == 0)
				data->als_contr &= ~LTR501_CONTR_ALS_GAIN_MASK;
			else
				return -EINVAL;

			return regmap_write(data->regmap, LTR501_ALS_CONTR,
					    data->als_contr);
		case IIO_PROXIMITY:
			i = ltr501_get_ps_gain_index(val, val2);
			if (i < 0)
				return -EINVAL;
			data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
			data->ps_contr |= i << LTR501_CONTR_PS_GAIN_SHIFT;

			return regmap_write(data->regmap, LTR501_PS_CONTR,
					    data->ps_contr);
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_INT_TIME:
		switch (chan->type) {
		case IIO_INTENSITY:
			if (val != 0)
				return -EINVAL;
			mutex_lock(&data->lock_als);
			i = ltr501_set_it_time(data, val2);
			mutex_unlock(&data->lock_als);
			return i;
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_SAMP_FREQ:
		switch (chan->type) {
		case IIO_INTENSITY:
			ret = ltr501_als_read_samp_freq(data, &freq_val,
							&freq_val2);
			if (ret < 0)
				return ret;

			ret = ltr501_als_write_samp_freq(data, val, val2);
			if (ret < 0)
				return ret;

			/* update persistence count when changing frequency */
			ret = ltr501_write_intr_prst(data, chan->type,
						     0, data->als_period);

			if (ret < 0)
				return ltr501_als_write_samp_freq(data,
								  freq_val,
								  freq_val2);
			return ret;
		case IIO_PROXIMITY:
			ret = ltr501_ps_read_samp_freq(data, &freq_val,
						       &freq_val2);
			if (ret < 0)
				return ret;

			ret = ltr501_ps_write_samp_freq(data, val, val2);
			if (ret < 0)
				return ret;

			/* update persistence count when changing frequency */
			ret = ltr501_write_intr_prst(data, chan->type,
						     0, data->ps_period);

			if (ret < 0)
				return ltr501_ps_write_samp_freq(data,
								 freq_val,
								 freq_val2);
			return ret;
		default:
			return -EINVAL;
		}
	}
	return -EINVAL;
}

static int ltr501_read_thresh(struct iio_dev *indio_dev,
			      const struct iio_chan_spec *chan,
			      enum iio_event_type type,
			      enum iio_event_direction dir,
			      enum iio_event_info info,
			      int *val, int *val2)
{
	struct ltr501_data *data = iio_priv(indio_dev);
	int ret, thresh_data;

	switch (chan->type) {
	case IIO_INTENSITY:
		switch (dir) {
		case IIO_EV_DIR_RISING:
			ret = regmap_bulk_read(data->regmap,
					       LTR501_ALS_THRESH_UP,
					       &thresh_data, 2);
			if (ret < 0)
				return ret;
			*val = thresh_data & LTR501_ALS_THRESH_MASK;
			return IIO_VAL_INT;
		case IIO_EV_DIR_FALLING:
			ret = regmap_bulk_read(data->regmap,
					       LTR501_ALS_THRESH_LOW,
					       &thresh_data, 2);
			if (ret < 0)
				return ret;
			*val = thresh_data & LTR501_ALS_THRESH_MASK;
			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
	case IIO_PROXIMITY:
		switch (dir) {
		case IIO_EV_DIR_RISING:
			ret = regmap_bulk_read(data->regmap,
					       LTR501_PS_THRESH_UP,
					       &thresh_data, 2);
			if (ret < 0)
				return ret;
			*val = thresh_data & LTR501_PS_THRESH_MASK;
			return IIO_VAL_INT;
		case IIO_EV_DIR_FALLING:
			ret = regmap_bulk_read(data->regmap,
					       LTR501_PS_THRESH_LOW,
					       &thresh_data, 2);
			if (ret < 0)
				return ret;
			*val = thresh_data & LTR501_PS_THRESH_MASK;
			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static int ltr501_write_thresh(struct iio_dev *indio_dev,
			       const struct iio_chan_spec *chan,
			       enum iio_event_type type,
			       enum iio_event_direction dir,
			       enum iio_event_info info,
			       int val, int val2)
{
	struct ltr501_data *data = iio_priv(indio_dev);
	int ret;

	if (val < 0)
		return -EINVAL;

	switch (chan->type) {
	case IIO_INTENSITY:
		if (val > LTR501_ALS_THRESH_MASK)
			return -EINVAL;
		switch (dir) {
		case IIO_EV_DIR_RISING:
			mutex_lock(&data->lock_als);
			ret = regmap_bulk_write(data->regmap,
						LTR501_ALS_THRESH_UP,
						&val, 2);
			mutex_unlock(&data->lock_als);
			return ret;
		case IIO_EV_DIR_FALLING:
			mutex_lock(&data->lock_als);
			ret = regmap_bulk_write(data->regmap,
						LTR501_ALS_THRESH_LOW,
						&val, 2);
			mutex_unlock(&data->lock_als);
			return ret;
		default:
			return -EINVAL;
		}
	case IIO_PROXIMITY:
		switch (dir) {
		if (val > LTR501_PS_THRESH_MASK)
			return -EINVAL;
		case IIO_EV_DIR_RISING:
			mutex_lock(&data->lock_ps);
			ret = regmap_bulk_write(data->regmap,
						LTR501_PS_THRESH_UP,
						&val, 2);
			mutex_unlock(&data->lock_ps);
			return ret;
		case IIO_EV_DIR_FALLING:
			mutex_lock(&data->lock_ps);
			ret = regmap_bulk_write(data->regmap,
						LTR501_PS_THRESH_LOW,
						&val, 2);
			mutex_unlock(&data->lock_ps);
			return ret;
		default:
			return -EINVAL;
		}
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static int ltr501_read_event(struct iio_dev *indio_dev,
			     const struct iio_chan_spec *chan,
			     enum iio_event_type type,
			     enum iio_event_direction dir,
			     enum iio_event_info info,
			     int *val, int *val2)
{
	int ret;

	switch (info) {
	case IIO_EV_INFO_VALUE:
		return ltr501_read_thresh(indio_dev, chan, type, dir,
					  info, val, val2);
	case IIO_EV_INFO_PERIOD:
		ret = ltr501_read_intr_prst(iio_priv(indio_dev),
					    chan->type, val2);
		*val = *val2 / 1000000;
		*val2 = *val2 % 1000000;
		return ret;
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static int ltr501_write_event(struct iio_dev *indio_dev,
			      const struct iio_chan_spec *chan,
			      enum iio_event_type type,
			      enum iio_event_direction dir,
			      enum iio_event_info info,
			      int val, int val2)
{
	switch (info) {
	case IIO_EV_INFO_VALUE:
		if (val2 != 0)
			return -EINVAL;
		return ltr501_write_thresh(indio_dev, chan, type, dir,
					   info, val, val2);
	case IIO_EV_INFO_PERIOD:
		return ltr501_write_intr_prst(iio_priv(indio_dev), chan->type,
					      val, val2);
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static int ltr501_read_event_config(struct iio_dev *indio_dev,
				    const struct iio_chan_spec *chan,
				    enum iio_event_type type,
				    enum iio_event_direction dir)
{
	struct ltr501_data *data = iio_priv(indio_dev);
	int ret, status;

	switch (chan->type) {
	case IIO_INTENSITY:
		ret = regmap_field_read(data->reg_als_intr, &status);
		if (ret < 0)
			return ret;
		return status;
	case IIO_PROXIMITY:
		ret = regmap_field_read(data->reg_ps_intr, &status);
		if (ret < 0)
			return ret;
		return status;
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static int ltr501_write_event_config(struct iio_dev *indio_dev,
				     const struct iio_chan_spec *chan,
				     enum iio_event_type type,
				     enum iio_event_direction dir, int state)
{
	struct ltr501_data *data = iio_priv(indio_dev);
	int ret;

	/* only 1 and 0 are valid inputs */
	if (state != 1  || state != 0)
		return -EINVAL;

	switch (chan->type) {
	case IIO_INTENSITY:
		mutex_lock(&data->lock_als);
		ret = regmap_field_write(data->reg_als_intr, state);
		mutex_unlock(&data->lock_als);
		return ret;
	case IIO_PROXIMITY:
		mutex_lock(&data->lock_ps);
		ret = regmap_field_write(data->reg_ps_intr, state);
		mutex_unlock(&data->lock_ps);
		return ret;
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static IIO_CONST_ATTR(in_proximity_scale_available, "1 0.25 0.125 0.0625");
static IIO_CONST_ATTR(in_intensity_scale_available, "1 0.005");
static IIO_CONST_ATTR_INT_TIME_AVAIL("0.05 0.1 0.2 0.4");
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");

static struct attribute *ltr501_attributes[] = {
	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
	&iio_const_attr_integration_time_available.dev_attr.attr,
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	NULL
};

static const struct attribute_group ltr501_attribute_group = {
	.attrs = ltr501_attributes,
};

static const struct iio_info ltr501_info_no_irq = {
	.read_raw = ltr501_read_raw,
	.write_raw = ltr501_write_raw,
	.attrs = &ltr501_attribute_group,
	.driver_module = THIS_MODULE,
};

static const struct iio_info ltr501_info = {
	.read_raw = ltr501_read_raw,
	.write_raw = ltr501_write_raw,
	.attrs = &ltr501_attribute_group,
	.read_event_value	= &ltr501_read_event,
	.write_event_value	= &ltr501_write_event,
	.read_event_config	= &ltr501_read_event_config,
	.write_event_config	= &ltr501_write_event_config,
	.driver_module = THIS_MODULE,
};

static int ltr501_write_contr(struct ltr501_data *data, u8 als_val, u8 ps_val)
{
	int ret;

	ret = regmap_write(data->regmap, LTR501_ALS_CONTR, als_val);
	if (ret < 0)
		return ret;

	return regmap_write(data->regmap, LTR501_PS_CONTR, ps_val);
}

static irqreturn_t ltr501_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ltr501_data *data = iio_priv(indio_dev);
	u16 buf[8];
	__le16 als_buf[2];
	u8 mask = 0;
	int j = 0;
	int ret, psdata;

	memset(buf, 0, sizeof(buf));

	/* figure out which data needs to be ready */
	if (test_bit(0, indio_dev->active_scan_mask) ||
	    test_bit(1, indio_dev->active_scan_mask))
		mask |= LTR501_STATUS_ALS_RDY;
	if (test_bit(2, indio_dev->active_scan_mask))
		mask |= LTR501_STATUS_PS_RDY;

	ret = ltr501_drdy(data, mask);
	if (ret < 0)
		goto done;

	if (mask & LTR501_STATUS_ALS_RDY) {
		ret = regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
				       (u8 *)als_buf, sizeof(als_buf));
		if (ret < 0)
			return ret;
		if (test_bit(0, indio_dev->active_scan_mask))
			buf[j++] = le16_to_cpu(als_buf[1]);
		if (test_bit(1, indio_dev->active_scan_mask))
			buf[j++] = le16_to_cpu(als_buf[0]);
	}

	if (mask & LTR501_STATUS_PS_RDY) {
		ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
				       &psdata, 2);
		if (ret < 0)
			goto done;
		buf[j++] = psdata & LTR501_PS_DATA_MASK;
	}

	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());

done:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static irqreturn_t ltr501_interrupt_handler(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct ltr501_data *data = iio_priv(indio_dev);
	int ret, status;

	ret = regmap_read(data->regmap, LTR501_ALS_PS_STATUS, &status);
	if (ret < 0) {
		dev_err(&data->client->dev,
			"irq read int reg failed\n");
		return IRQ_HANDLED;
	}

	if (status & LTR501_STATUS_ALS_INTR)
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_EITHER),
			       iio_get_time_ns());

	if (status & LTR501_STATUS_PS_INTR)
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_EITHER),
			       iio_get_time_ns());

	return IRQ_HANDLED;
}

static int ltr501_init(struct ltr501_data *data)
{
	int ret, status;

	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
	if (ret < 0)
		return ret;

	data->als_contr = status | LTR501_CONTR_ACTIVE;

	ret = regmap_read(data->regmap, LTR501_PS_CONTR, &status);
	if (ret < 0)
		return ret;

	data->ps_contr = status | LTR501_CONTR_ACTIVE;

	ret = ltr501_read_intr_prst(data, IIO_INTENSITY, &data->als_period);
	if (ret < 0)
		return ret;

	ret = ltr501_read_intr_prst(data, IIO_PROXIMITY, &data->ps_period);
	if (ret < 0)
		return ret;

	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
}

static bool ltr501_is_volatile_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case LTR501_ALS_DATA1:
	case LTR501_ALS_DATA0:
	case LTR501_ALS_PS_STATUS:
	case LTR501_PS_DATA:
		return true;
	default:
		return false;
	}
}

static struct regmap_config ltr501_regmap_config = {
	.name =  LTR501_REGMAP_NAME,
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = LTR501_MAX_REG,
	.cache_type = REGCACHE_RBTREE,
	.volatile_reg = ltr501_is_volatile_reg,
};

static int ltr501_powerdown(struct ltr501_data *data)
{
	return ltr501_write_contr(data, data->als_contr & ~LTR501_CONTR_ACTIVE,
				  data->ps_contr & ~LTR501_CONTR_ACTIVE);
}

static int ltr501_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct ltr501_data *data;
	struct iio_dev *indio_dev;
	struct regmap *regmap;
	int ret, partid;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	regmap = devm_regmap_init_i2c(client, &ltr501_regmap_config);
	if (IS_ERR(regmap)) {
		dev_err(&client->dev, "Regmap initialization failed.\n");
		return PTR_ERR(regmap);
	}

	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;
	data->regmap = regmap;
	mutex_init(&data->lock_als);
	mutex_init(&data->lock_ps);

	data->reg_it = devm_regmap_field_alloc(&client->dev, regmap,
					       reg_field_it);
	if (IS_ERR(data->reg_it)) {
		dev_err(&client->dev, "Integ time reg field init failed.\n");
		return PTR_ERR(data->reg_it);
	}

	data->reg_als_intr = devm_regmap_field_alloc(&client->dev, regmap,
						     reg_field_als_intr);
	if (IS_ERR(data->reg_als_intr)) {
		dev_err(&client->dev, "ALS intr mode reg field init failed\n");
		return PTR_ERR(data->reg_als_intr);
	}

	data->reg_ps_intr = devm_regmap_field_alloc(&client->dev, regmap,
						    reg_field_ps_intr);
	if (IS_ERR(data->reg_ps_intr)) {
		dev_err(&client->dev, "PS intr mode reg field init failed.\n");
		return PTR_ERR(data->reg_ps_intr);
	}

	data->reg_als_rate = devm_regmap_field_alloc(&client->dev, regmap,
						     reg_field_als_rate);
	if (IS_ERR(data->reg_als_rate)) {
		dev_err(&client->dev, "ALS samp rate field init failed.\n");
		return PTR_ERR(data->reg_als_rate);
	}

	data->reg_ps_rate = devm_regmap_field_alloc(&client->dev, regmap,
						    reg_field_ps_rate);
	if (IS_ERR(data->reg_ps_rate)) {
		dev_err(&client->dev, "PS samp rate field init failed.\n");
		return PTR_ERR(data->reg_ps_rate);
	}

	data->reg_als_prst = devm_regmap_field_alloc(&client->dev, regmap,
						     reg_field_als_prst);
	if (IS_ERR(data->reg_als_prst)) {
		dev_err(&client->dev, "ALS prst reg field init failed\n");
		return PTR_ERR(data->reg_als_prst);
	}

	data->reg_ps_prst = devm_regmap_field_alloc(&client->dev, regmap,
						    reg_field_ps_prst);
	if (IS_ERR(data->reg_ps_prst)) {
		dev_err(&client->dev, "PS prst reg field init failed.\n");
		return PTR_ERR(data->reg_ps_prst);
	}

	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
	if (ret < 0)
		return ret;
	if ((partid >> 4) != 0x8)
		return -ENODEV;

	indio_dev->dev.parent = &client->dev;
	indio_dev->channels = ltr501_channels;
	indio_dev->num_channels = ARRAY_SIZE(ltr501_channels);
	indio_dev->name = LTR501_DRV_NAME;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = ltr501_init(data);
	if (ret < 0)
		return ret;

	if (client->irq > 0) {
		indio_dev->info = &ltr501_info;
		ret = devm_request_threaded_irq(&client->dev, client->irq,
						NULL, ltr501_interrupt_handler,
						IRQF_TRIGGER_FALLING |
						IRQF_ONESHOT,
						"ltr501_thresh_event",
						indio_dev);
		if (ret) {
			dev_err(&client->dev, "request irq (%d) failed\n",
				client->irq);
			return ret;
		}
	} else {
		indio_dev->info = &ltr501_info_no_irq;
	}

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
					 ltr501_trigger_handler, NULL);
	if (ret)
		goto powerdown_on_error;

	ret = iio_device_register(indio_dev);
	if (ret)
		goto error_unreg_buffer;

	return 0;

error_unreg_buffer:
	iio_triggered_buffer_cleanup(indio_dev);
powerdown_on_error:
	ltr501_powerdown(data);
	return ret;
}

static int ltr501_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	ltr501_powerdown(iio_priv(indio_dev));

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int ltr501_suspend(struct device *dev)
{
	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
					    to_i2c_client(dev)));
	return ltr501_powerdown(data);
}

static int ltr501_resume(struct device *dev)
{
	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
					    to_i2c_client(dev)));

	return ltr501_write_contr(data, data->als_contr,
		data->ps_contr);
}
#endif

static SIMPLE_DEV_PM_OPS(ltr501_pm_ops, ltr501_suspend, ltr501_resume);

static const struct acpi_device_id ltr_acpi_match[] = {
	{"LTER0501", 0},
	{ },
};
MODULE_DEVICE_TABLE(acpi, ltr_acpi_match);

static const struct i2c_device_id ltr501_id[] = {
	{ "ltr501", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ltr501_id);

static struct i2c_driver ltr501_driver = {
	.driver = {
		.name   = LTR501_DRV_NAME,
		.pm	= &ltr501_pm_ops,
		.acpi_match_table = ACPI_PTR(ltr_acpi_match),
		.owner  = THIS_MODULE,
	},
	.probe  = ltr501_probe,
	.remove	= ltr501_remove,
	.id_table = ltr501_id,
};

module_i2c_driver(ltr501_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Lite-On LTR501 ambient light and proximity sensor driver");
MODULE_LICENSE("GPL");