/*
 * apds9960.c - Support for Avago APDS9960 gesture/RGB/ALS/proximity sensor
 *
 * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
 *
 * 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.
 *
 * TODO: gesture + proximity calib offsets
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/events.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/sysfs.h>
#include <linux/of_gpio.h>

#define APDS9960_REGMAP_NAME	"apds9960_regmap"
#define APDS9960_DRV_NAME	"apds9960"

#define APDS9960_REG_RAM_START	0x00
#define APDS9960_REG_RAM_END	0x7f

#define APDS9960_REG_ENABLE	0x80
#define APDS9960_REG_ATIME	0x81
#define APDS9960_REG_WTIME	0x83

#define APDS9960_REG_AILTL	0x84
#define APDS9960_REG_AILTH	0x85
#define APDS9960_REG_AIHTL	0x86
#define APDS9960_REG_AIHTH	0x87

#define APDS9960_REG_PILT	0x89
#define APDS9960_REG_PIHT	0x8b
#define APDS9960_REG_PERS	0x8c

#define APDS9960_REG_CONFIG_1	0x8d
#define APDS9960_REG_PPULSE	0x8e

#define APDS9960_REG_CONTROL	0x8f
#define APDS9960_REG_CONTROL_AGAIN_MASK		0x03
#define APDS9960_REG_CONTROL_PGAIN_MASK		0x0c
#define APDS9960_REG_CONTROL_AGAIN_MASK_SHIFT	0
#define APDS9960_REG_CONTROL_PGAIN_MASK_SHIFT	2

#define APDS9960_REG_CONFIG_2	0x90
#define APDS9960_REG_CONFIG_2_GGAIN_MASK	0x60
#define APDS9960_REG_CONFIG_2_GGAIN_MASK_SHIFT	5

#define APDS9960_REG_ID		0x92

#define APDS9960_REG_STATUS	0x93
#define APDS9960_REG_STATUS_PS_INT	BIT(5)
#define APDS9960_REG_STATUS_ALS_INT	BIT(4)
#define APDS9960_REG_STATUS_GINT	BIT(2)

#define APDS9960_REG_PDATA	0x9c
#define APDS9960_REG_POFFSET_UR	0x9d
#define APDS9960_REG_POFFSET_DL 0x9e
#define APDS9960_REG_CONFIG_3	0x9f

#define APDS9960_REG_GPENTH	0xa0
#define APDS9960_REG_GEXTH	0xa1

#define APDS9960_REG_GCONF_1	0xa2
#define APDS9960_REG_GCONF_1_GFIFO_THRES_MASK		0xc0
#define APDS9960_REG_GCONF_1_GFIFO_THRES_MASK_SHIFT	6

#define APDS9960_REG_GCONF_2	0xa3
#define APDS9960_REG_GOFFSET_U	0xa4
#define APDS9960_REG_GOFFSET_D	0xa5
#define APDS9960_REG_GPULSE	0xa6
#define APDS9960_REG_GOFFSET_L	0xa7
#define APDS9960_REG_GOFFSET_R	0xa9
#define APDS9960_REG_GCONF_3	0xaa

#define APDS9960_REG_GCONF_4	0xab
#define APDS9960_REG_GFLVL	0xae
#define APDS9960_REG_GSTATUS	0xaf

#define APDS9960_REG_IFORCE	0xe4
#define APDS9960_REG_PICLEAR	0xe5
#define APDS9960_REG_CICLEAR	0xe6
#define APDS9960_REG_AICLEAR	0xe7

#define APDS9960_DEFAULT_PERS	0x33
#define APDS9960_DEFAULT_GPENTH	0x50
#define APDS9960_DEFAULT_GEXTH	0x40

#define APDS9960_MAX_PXS_THRES_VAL	255
#define APDS9960_MAX_ALS_THRES_VAL	0xffff
#define APDS9960_MAX_INT_TIME_IN_US	1000000

enum apds9960_als_channel_idx {
	IDX_ALS_CLEAR, IDX_ALS_RED, IDX_ALS_GREEN, IDX_ALS_BLUE,
};

#define APDS9960_REG_ALS_BASE	0x94
#define APDS9960_REG_ALS_CHANNEL(_colour) \
	(APDS9960_REG_ALS_BASE + (IDX_ALS_##_colour * 2))

enum apds9960_gesture_channel_idx {
	IDX_DIR_UP, IDX_DIR_DOWN, IDX_DIR_LEFT, IDX_DIR_RIGHT,
};

#define APDS9960_REG_GFIFO_BASE	0xfc
#define APDS9960_REG_GFIFO_DIR(_dir) \
	(APDS9960_REG_GFIFO_BASE + IDX_DIR_##_dir)

struct apds9960_data {
	struct i2c_client *client;
	struct iio_dev *indio_dev;
	struct mutex lock;

	/* regmap fields */
	struct regmap *regmap;
	struct regmap_field *reg_int_als;
	struct regmap_field *reg_int_ges;
	struct regmap_field *reg_int_pxs;

	struct regmap_field *reg_enable_als;
	struct regmap_field *reg_enable_ges;
	struct regmap_field *reg_enable_pxs;

	/* state */
	int als_int;
	int pxs_int;
	int gesture_mode_running;

	/* gain values */
	int als_gain;
	int pxs_gain;

	/* integration time value in us */
	int als_adc_int_us;

	/* gesture buffer */
	u8 buffer[4]; /* 4 8-bit channels */
};

static const struct reg_default apds9960_reg_defaults[] = {
	/* Default ALS integration time = 2.48ms */
	{ APDS9960_REG_ATIME, 0xff },
};

static const struct regmap_range apds9960_volatile_ranges[] = {
	regmap_reg_range(APDS9960_REG_STATUS,
				APDS9960_REG_PDATA),
	regmap_reg_range(APDS9960_REG_GFLVL,
				APDS9960_REG_GSTATUS),
	regmap_reg_range(APDS9960_REG_GFIFO_DIR(UP),
				APDS9960_REG_GFIFO_DIR(RIGHT)),
	regmap_reg_range(APDS9960_REG_IFORCE,
				APDS9960_REG_AICLEAR),
};

static const struct regmap_access_table apds9960_volatile_table = {
	.yes_ranges	= apds9960_volatile_ranges,
	.n_yes_ranges	= ARRAY_SIZE(apds9960_volatile_ranges),
};

static const struct regmap_range apds9960_precious_ranges[] = {
	regmap_reg_range(APDS9960_REG_RAM_START, APDS9960_REG_RAM_END),
};

static const struct regmap_access_table apds9960_precious_table = {
	.yes_ranges	= apds9960_precious_ranges,
	.n_yes_ranges	= ARRAY_SIZE(apds9960_precious_ranges),
};

static const struct regmap_range apds9960_readable_ranges[] = {
	regmap_reg_range(APDS9960_REG_ENABLE,
				APDS9960_REG_GSTATUS),
	regmap_reg_range(APDS9960_REG_GFIFO_DIR(UP),
				APDS9960_REG_GFIFO_DIR(RIGHT)),
};

static const struct regmap_access_table apds9960_readable_table = {
	.yes_ranges	= apds9960_readable_ranges,
	.n_yes_ranges	= ARRAY_SIZE(apds9960_readable_ranges),
};

static const struct regmap_range apds9960_writeable_ranges[] = {
	regmap_reg_range(APDS9960_REG_ENABLE, APDS9960_REG_CONFIG_2),
	regmap_reg_range(APDS9960_REG_POFFSET_UR, APDS9960_REG_GCONF_4),
	regmap_reg_range(APDS9960_REG_IFORCE, APDS9960_REG_AICLEAR),
};

static const struct regmap_access_table apds9960_writeable_table = {
	.yes_ranges	= apds9960_writeable_ranges,
	.n_yes_ranges	= ARRAY_SIZE(apds9960_writeable_ranges),
};

static const struct regmap_config apds9960_regmap_config = {
	.name = APDS9960_REGMAP_NAME,
	.reg_bits = 8,
	.val_bits = 8,
	.use_single_rw = 1,

	.volatile_table = &apds9960_volatile_table,
	.precious_table = &apds9960_precious_table,
	.rd_table = &apds9960_readable_table,
	.wr_table = &apds9960_writeable_table,

	.reg_defaults = apds9960_reg_defaults,
	.num_reg_defaults = ARRAY_SIZE(apds9960_reg_defaults),
	.max_register = APDS9960_REG_GFIFO_DIR(RIGHT),
	.cache_type = REGCACHE_RBTREE,
};

static const struct iio_event_spec apds9960_pxs_event_spec[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	},
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	},
};

static const struct iio_event_spec apds9960_als_event_spec[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	},
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
			BIT(IIO_EV_INFO_ENABLE),
	},
};

#define APDS9960_GESTURE_CHANNEL(_dir, _si) { \
	.type = IIO_PROXIMITY, \
	.channel = _si + 1, \
	.scan_index = _si, \
	.indexed = 1, \
	.scan_type = { \
		.sign = 'u', \
		.realbits = 8, \
		.storagebits = 8, \
	}, \
}

#define APDS9960_INTENSITY_CHANNEL(_colour) { \
	.type = IIO_INTENSITY, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
			BIT(IIO_CHAN_INFO_INT_TIME), \
	.channel2 = IIO_MOD_LIGHT_##_colour, \
	.address = APDS9960_REG_ALS_CHANNEL(_colour), \
	.modified = 1, \
	.scan_index = -1, \
}

static const unsigned long apds9960_scan_masks[] = {0xf, 0};

static const struct iio_chan_spec apds9960_channels[] = {
	{
		.type = IIO_PROXIMITY,
		.address = APDS9960_REG_PDATA,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
		.channel = 0,
		.indexed = 0,
		.scan_index = -1,

		.event_spec = apds9960_pxs_event_spec,
		.num_event_specs = ARRAY_SIZE(apds9960_pxs_event_spec),
	},
	/* Gesture Sensor */
	APDS9960_GESTURE_CHANNEL(UP, 0),
	APDS9960_GESTURE_CHANNEL(DOWN, 1),
	APDS9960_GESTURE_CHANNEL(LEFT, 2),
	APDS9960_GESTURE_CHANNEL(RIGHT, 3),
	/* ALS */
	{
		.type = IIO_INTENSITY,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
			BIT(IIO_CHAN_INFO_INT_TIME),
		.channel2 = IIO_MOD_LIGHT_CLEAR,
		.address = APDS9960_REG_ALS_CHANNEL(CLEAR),
		.modified = 1,
		.scan_index = -1,

		.event_spec = apds9960_als_event_spec,
		.num_event_specs = ARRAY_SIZE(apds9960_als_event_spec),
	},
	/* RGB Sensor */
	APDS9960_INTENSITY_CHANNEL(RED),
	APDS9960_INTENSITY_CHANNEL(GREEN),
	APDS9960_INTENSITY_CHANNEL(BLUE),
};

/* integration time in us */
static const int apds9960_int_time[][2] = {
	{ 28000, 246},
	{100000, 219},
	{200000, 182},
	{700000,   0}
};

/* gain mapping */
static const int apds9960_pxs_gain_map[] = {1, 2, 4, 8};
static const int apds9960_als_gain_map[] = {1, 4, 16, 64};

static IIO_CONST_ATTR(proximity_scale_available, "1 2 4 8");
static IIO_CONST_ATTR(intensity_scale_available, "1 4 16 64");
static IIO_CONST_ATTR_INT_TIME_AVAIL("0.028 0.1 0.2 0.7");

static struct attribute *apds9960_attributes[] = {
	&iio_const_attr_proximity_scale_available.dev_attr.attr,
	&iio_const_attr_intensity_scale_available.dev_attr.attr,
	&iio_const_attr_integration_time_available.dev_attr.attr,
	NULL,
};

static struct attribute_group apds9960_attribute_group = {
	.attrs = apds9960_attributes,
};

static const struct reg_field apds9960_reg_field_int_als =
				REG_FIELD(APDS9960_REG_ENABLE, 4, 4);

static const struct reg_field apds9960_reg_field_int_ges =
				REG_FIELD(APDS9960_REG_GCONF_4, 1, 1);

static const struct reg_field apds9960_reg_field_int_pxs =
				REG_FIELD(APDS9960_REG_ENABLE, 5, 5);

static const struct reg_field apds9960_reg_field_enable_als =
				REG_FIELD(APDS9960_REG_ENABLE, 1, 1);

static const struct reg_field apds9960_reg_field_enable_ges =
				REG_FIELD(APDS9960_REG_ENABLE, 6, 6);

static const struct reg_field apds9960_reg_field_enable_pxs =
				REG_FIELD(APDS9960_REG_ENABLE, 2, 2);

static int apds9960_set_it_time(struct apds9960_data *data, int val2)
{
	int ret = -EINVAL;
	int idx;

	for (idx = 0; idx < ARRAY_SIZE(apds9960_int_time); idx++) {
		if (apds9960_int_time[idx][0] == val2) {
			mutex_lock(&data->lock);
			ret = regmap_write(data->regmap, APDS9960_REG_ATIME,
						 apds9960_int_time[idx][1]);
			if (!ret)
				data->als_adc_int_us = val2;
			mutex_unlock(&data->lock);
			break;
		}
	}

	return ret;
}

static int apds9960_set_pxs_gain(struct apds9960_data *data, int val)
{
	int ret = -EINVAL;
	int idx;

	for (idx = 0; idx < ARRAY_SIZE(apds9960_pxs_gain_map); idx++) {
		if (apds9960_pxs_gain_map[idx] == val) {
			/* pxs + gesture gains are mirrored */
			mutex_lock(&data->lock);
			ret = regmap_update_bits(data->regmap,
				APDS9960_REG_CONTROL,
				APDS9960_REG_CONTROL_PGAIN_MASK,
				idx << APDS9960_REG_CONTROL_PGAIN_MASK_SHIFT);
			if (ret) {
				mutex_unlock(&data->lock);
				break;
			}

			ret = regmap_update_bits(data->regmap,
				APDS9960_REG_CONFIG_2,
				APDS9960_REG_CONFIG_2_GGAIN_MASK,
				idx << APDS9960_REG_CONFIG_2_GGAIN_MASK_SHIFT);
			if (!ret)
				data->pxs_gain = idx;
			mutex_unlock(&data->lock);
			break;
		}
	}

	return ret;
}

static int apds9960_set_als_gain(struct apds9960_data *data, int val)
{
	int ret = -EINVAL;
	int idx;

	for (idx = 0; idx < ARRAY_SIZE(apds9960_als_gain_map); idx++) {
		if (apds9960_als_gain_map[idx] == val) {
			mutex_lock(&data->lock);
			ret = regmap_update_bits(data->regmap,
					APDS9960_REG_CONTROL,
					APDS9960_REG_CONTROL_AGAIN_MASK, idx);
			if (!ret)
				data->als_gain = idx;
			mutex_unlock(&data->lock);
			break;
		}
	}

	return ret;
}

#ifdef CONFIG_PM
static int apds9960_set_power_state(struct apds9960_data *data, bool on)
{
	struct device *dev = &data->client->dev;
	int ret = 0;

	mutex_lock(&data->lock);

	if (on) {
		int suspended;

		suspended = pm_runtime_suspended(dev);
		ret = pm_runtime_get_sync(dev);

		/* Allow one integration cycle before allowing a reading */
		if (suspended)
			usleep_range(data->als_adc_int_us,
				     APDS9960_MAX_INT_TIME_IN_US);
	} else {
		pm_runtime_mark_last_busy(dev);
		ret = pm_runtime_put_autosuspend(dev);
	}

	mutex_unlock(&data->lock);

	return ret;
}
#else
static int apds9960_set_power_state(struct apds9960_data *data, bool on)
{
	return 0;
}
#endif

static int apds9960_read_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int *val, int *val2, long mask)
{
	struct apds9960_data *data = iio_priv(indio_dev);
	__le16 buf;
	int ret = -EINVAL;

	if (data->gesture_mode_running)
		return -EBUSY;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		apds9960_set_power_state(data, true);
		switch (chan->type) {
		case IIO_PROXIMITY:
			ret = regmap_read(data->regmap, chan->address, val);
			if (!ret)
				ret = IIO_VAL_INT;
			break;
		case IIO_INTENSITY:
			ret = regmap_bulk_read(data->regmap, chan->address,
					       &buf, 2);
			if (!ret) {
				ret = IIO_VAL_INT;
				*val = le16_to_cpu(buf);
			}
			break;
		default:
			ret = -EINVAL;
		}
		apds9960_set_power_state(data, false);
		break;
	case IIO_CHAN_INFO_INT_TIME:
		/* RGB + ALS sensors only have integration time */
		mutex_lock(&data->lock);
		switch (chan->type) {
		case IIO_INTENSITY:
			*val = 0;
			*val2 = data->als_adc_int_us;
			ret = IIO_VAL_INT_PLUS_MICRO;
			break;
		default:
			ret = -EINVAL;
		}
		mutex_unlock(&data->lock);
		break;
	case IIO_CHAN_INFO_SCALE:
		mutex_lock(&data->lock);
		switch (chan->type) {
		case IIO_PROXIMITY:
			*val = apds9960_pxs_gain_map[data->pxs_gain];
			ret = IIO_VAL_INT;
			break;
		case IIO_INTENSITY:
			*val = apds9960_als_gain_map[data->als_gain];
			ret = IIO_VAL_INT;
			break;
		default:
			ret = -EINVAL;
		}
		mutex_unlock(&data->lock);
		break;
	}

	return ret;
};

static int apds9960_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct apds9960_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
		/* RGB + ALS sensors only have int time */
		switch (chan->type) {
		case IIO_INTENSITY:
			if (val != 0)
				return -EINVAL;
			return apds9960_set_it_time(data, val2);
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_SCALE:
		if (val2 != 0)
			return -EINVAL;
		switch (chan->type) {
		case IIO_PROXIMITY:
			return apds9960_set_pxs_gain(data, val);
		case IIO_INTENSITY:
			return apds9960_set_als_gain(data, val);
		default:
			return -EINVAL;
		}
	default:
		return -EINVAL;
	};

	return 0;
}

static inline int apds9960_get_thres_reg(const struct iio_chan_spec *chan,
					 enum iio_event_direction dir,
					 u8 *reg)
{
	switch (dir) {
	case IIO_EV_DIR_RISING:
		switch (chan->type) {
		case IIO_PROXIMITY:
			*reg = APDS9960_REG_PIHT;
			break;
		case IIO_INTENSITY:
			*reg = APDS9960_REG_AIHTL;
			break;
		default:
			return -EINVAL;
		}
		break;
	case IIO_EV_DIR_FALLING:
		switch (chan->type) {
		case IIO_PROXIMITY:
			*reg = APDS9960_REG_PILT;
			break;
		case IIO_INTENSITY:
			*reg = APDS9960_REG_AILTL;
			break;
		default:
			return -EINVAL;
		}
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int apds9960_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)
{
	u8 reg;
	__le16 buf;
	int ret = 0;
	struct apds9960_data *data = iio_priv(indio_dev);

	if (info != IIO_EV_INFO_VALUE)
		return -EINVAL;

	ret = apds9960_get_thres_reg(chan, dir, &reg);
	if (ret < 0)
		return ret;

	if (chan->type == IIO_PROXIMITY) {
		ret = regmap_read(data->regmap, reg, val);
		if (ret < 0)
			return ret;
	} else if (chan->type == IIO_INTENSITY) {
		ret = regmap_bulk_read(data->regmap, reg, &buf, 2);
		if (ret < 0)
			return ret;
		*val = le16_to_cpu(buf);
	} else
		return -EINVAL;

	*val2 = 0;

	return IIO_VAL_INT;
}

static int apds9960_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)
{
	u8 reg;
	__le16 buf;
	int ret = 0;
	struct apds9960_data *data = iio_priv(indio_dev);

	if (info != IIO_EV_INFO_VALUE)
		return -EINVAL;

	ret = apds9960_get_thres_reg(chan, dir, &reg);
	if (ret < 0)
		return ret;

	if (chan->type == IIO_PROXIMITY) {
		if (val < 0 || val > APDS9960_MAX_PXS_THRES_VAL)
			return -EINVAL;
		ret = regmap_write(data->regmap, reg, val);
		if (ret < 0)
			return ret;
	} else if (chan->type == IIO_INTENSITY) {
		if (val < 0 || val > APDS9960_MAX_ALS_THRES_VAL)
			return -EINVAL;
		buf = cpu_to_le16(val);
		ret = regmap_bulk_write(data->regmap, reg, &buf, 2);
		if (ret < 0)
			return ret;
	} else
		return -EINVAL;

	return 0;
}

static int apds9960_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 apds9960_data *data = iio_priv(indio_dev);

	switch (chan->type) {
	case IIO_PROXIMITY:
		return data->pxs_int;
	case IIO_INTENSITY:
		return data->als_int;
	default:
		return -EINVAL;
	}

	return 0;
}

static int apds9960_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 apds9960_data *data = iio_priv(indio_dev);
	int ret;

	state = !!state;

	switch (chan->type) {
	case IIO_PROXIMITY:
		if (data->pxs_int == state)
			return -EINVAL;

		ret = regmap_field_write(data->reg_int_pxs, state);
		if (ret)
			return ret;
		data->pxs_int = state;
		apds9960_set_power_state(data, state);
		break;
	case IIO_INTENSITY:
		if (data->als_int == state)
			return -EINVAL;

		ret = regmap_field_write(data->reg_int_als, state);
		if (ret)
			return ret;
		data->als_int = state;
		apds9960_set_power_state(data, state);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static const struct iio_info apds9960_info = {
	.driver_module = THIS_MODULE,
	.attrs = &apds9960_attribute_group,
	.read_raw = apds9960_read_raw,
	.write_raw = apds9960_write_raw,
	.read_event_value = apds9960_read_event,
	.write_event_value = apds9960_write_event,
	.read_event_config = apds9960_read_event_config,
	.write_event_config = apds9960_write_event_config,

};

static inline int apds9660_fifo_is_empty(struct apds9960_data *data)
{
	int cnt;
	int ret;

	ret = regmap_read(data->regmap, APDS9960_REG_GFLVL, &cnt);
	if (ret)
		return ret;

	return cnt;
}

static void apds9960_read_gesture_fifo(struct apds9960_data *data)
{
	int ret, cnt = 0;

	mutex_lock(&data->lock);
	data->gesture_mode_running = 1;

	while (cnt || (cnt = apds9660_fifo_is_empty(data) > 0)) {
		ret = regmap_bulk_read(data->regmap, APDS9960_REG_GFIFO_BASE,
				      &data->buffer, 4);

		if (ret)
			goto err_read;

		iio_push_to_buffers(data->indio_dev, data->buffer);
		cnt--;
	}

err_read:
	data->gesture_mode_running = 0;
	mutex_unlock(&data->lock);
}

static irqreturn_t apds9960_interrupt_handler(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct apds9960_data *data = iio_priv(indio_dev);
	int ret, status;

	ret = regmap_read(data->regmap, APDS9960_REG_STATUS, &status);
	if (ret < 0) {
		dev_err(&data->client->dev, "irq status reg read failed\n");
		return IRQ_HANDLED;
	}

	if ((status & APDS9960_REG_STATUS_ALS_INT) && data->als_int) {
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_EITHER),
			       iio_get_time_ns(indio_dev));
		regmap_write(data->regmap, APDS9960_REG_CICLEAR, 1);
	}

	if ((status & APDS9960_REG_STATUS_PS_INT) && data->pxs_int) {
		iio_push_event(indio_dev,
			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
						    IIO_EV_TYPE_THRESH,
						    IIO_EV_DIR_EITHER),
			       iio_get_time_ns(indio_dev));
		regmap_write(data->regmap, APDS9960_REG_PICLEAR, 1);
	}

	if (status & APDS9960_REG_STATUS_GINT)
		apds9960_read_gesture_fifo(data);

	return IRQ_HANDLED;
}

static int apds9960_set_powermode(struct apds9960_data *data, bool state)
{
	return regmap_update_bits(data->regmap, APDS9960_REG_ENABLE, 1, state);
}

static int apds9960_buffer_postenable(struct iio_dev *indio_dev)
{
	struct apds9960_data *data = iio_priv(indio_dev);
	int ret;

	ret = regmap_field_write(data->reg_int_ges, 1);
	if (ret)
		return ret;

	ret = regmap_field_write(data->reg_enable_ges, 1);
	if (ret)
		return ret;

	pm_runtime_get_sync(&data->client->dev);

	return 0;
}

static int apds9960_buffer_predisable(struct iio_dev *indio_dev)
{
	struct apds9960_data *data = iio_priv(indio_dev);
	int ret;

	ret = regmap_field_write(data->reg_enable_ges, 0);
	if (ret)
		return ret;

	ret = regmap_field_write(data->reg_int_ges, 0);
	if (ret)
		return ret;

	pm_runtime_put_autosuspend(&data->client->dev);

	return 0;
}

static const struct iio_buffer_setup_ops apds9960_buffer_setup_ops = {
	.postenable = apds9960_buffer_postenable,
	.predisable = apds9960_buffer_predisable,
};

static int apds9960_regfield_init(struct apds9960_data *data)
{
	struct device *dev = &data->client->dev;
	struct regmap *regmap = data->regmap;

	data->reg_int_als = devm_regmap_field_alloc(dev, regmap,
						apds9960_reg_field_int_als);
	if (IS_ERR(data->reg_int_als)) {
		dev_err(dev, "INT ALS reg field init failed\n");
		return PTR_ERR(data->reg_int_als);
	}

	data->reg_int_ges = devm_regmap_field_alloc(dev, regmap,
						apds9960_reg_field_int_ges);
	if (IS_ERR(data->reg_int_ges)) {
		dev_err(dev, "INT gesture reg field init failed\n");
		return PTR_ERR(data->reg_int_ges);
	}

	data->reg_int_pxs = devm_regmap_field_alloc(dev, regmap,
						apds9960_reg_field_int_pxs);
	if (IS_ERR(data->reg_int_pxs)) {
		dev_err(dev, "INT pxs reg field init failed\n");
		return PTR_ERR(data->reg_int_pxs);
	}

	data->reg_enable_als = devm_regmap_field_alloc(dev, regmap,
						apds9960_reg_field_enable_als);
	if (IS_ERR(data->reg_enable_als)) {
		dev_err(dev, "Enable ALS reg field init failed\n");
		return PTR_ERR(data->reg_enable_als);
	}

	data->reg_enable_ges = devm_regmap_field_alloc(dev, regmap,
						apds9960_reg_field_enable_ges);
	if (IS_ERR(data->reg_enable_ges)) {
		dev_err(dev, "Enable gesture reg field init failed\n");
		return PTR_ERR(data->reg_enable_ges);
	}

	data->reg_enable_pxs = devm_regmap_field_alloc(dev, regmap,
						apds9960_reg_field_enable_pxs);
	if (IS_ERR(data->reg_enable_pxs)) {
		dev_err(dev, "Enable PXS reg field init failed\n");
		return PTR_ERR(data->reg_enable_pxs);
	}

	return 0;
}

static int apds9960_chip_init(struct apds9960_data *data)
{
	int ret;

	/* Default IT for ALS of 28 ms */
	ret = apds9960_set_it_time(data, 28000);
	if (ret)
		return ret;

	/* Ensure gesture interrupt is OFF */
	ret = regmap_field_write(data->reg_int_ges, 0);
	if (ret)
		return ret;

	/* Disable gesture sensor, since polling is useless from user-space */
	ret = regmap_field_write(data->reg_enable_ges, 0);
	if (ret)
		return ret;

	/* Ensure proximity interrupt is OFF */
	ret = regmap_field_write(data->reg_int_pxs, 0);
	if (ret)
		return ret;

	/* Enable proximity sensor for polling */
	ret = regmap_field_write(data->reg_enable_pxs, 1);
	if (ret)
		return ret;

	/* Ensure ALS interrupt is OFF */
	ret = regmap_field_write(data->reg_int_als, 0);
	if (ret)
		return ret;

	/* Enable ALS sensor for polling */
	ret = regmap_field_write(data->reg_enable_als, 1);
	if (ret)
		return ret;
	/*
	 * When enabled trigger an interrupt after 3 readings
	 * outside threshold for ALS + PXS
	 */
	ret = regmap_write(data->regmap, APDS9960_REG_PERS,
			   APDS9960_DEFAULT_PERS);
	if (ret)
		return ret;

	/*
	 * Wait for 4 event outside gesture threshold to prevent interrupt
	 * flooding.
	 */
	ret = regmap_update_bits(data->regmap, APDS9960_REG_GCONF_1,
			APDS9960_REG_GCONF_1_GFIFO_THRES_MASK,
			BIT(0) << APDS9960_REG_GCONF_1_GFIFO_THRES_MASK_SHIFT);
	if (ret)
		return ret;

	/* Default ENTER and EXIT thresholds for the GESTURE engine. */
	ret = regmap_write(data->regmap, APDS9960_REG_GPENTH,
			   APDS9960_DEFAULT_GPENTH);
	if (ret)
		return ret;

	ret = regmap_write(data->regmap, APDS9960_REG_GEXTH,
			   APDS9960_DEFAULT_GEXTH);
	if (ret)
		return ret;

	return apds9960_set_powermode(data, 1);
}

static int apds9960_probe(struct i2c_client *client,
			  const struct i2c_device_id *id)
{
	struct apds9960_data *data;
	struct iio_buffer *buffer;
	struct iio_dev *indio_dev;
	int ret;

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

	buffer = devm_iio_kfifo_allocate(&client->dev);
	if (!buffer)
		return -ENOMEM;

	iio_device_attach_buffer(indio_dev, buffer);

	indio_dev->dev.parent = &client->dev;
	indio_dev->info = &apds9960_info;
	indio_dev->name = APDS9960_DRV_NAME;
	indio_dev->channels = apds9960_channels;
	indio_dev->num_channels = ARRAY_SIZE(apds9960_channels);
	indio_dev->available_scan_masks = apds9960_scan_masks;
	indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
	indio_dev->setup_ops = &apds9960_buffer_setup_ops;

	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);

	data->regmap = devm_regmap_init_i2c(client, &apds9960_regmap_config);
	if (IS_ERR(data->regmap)) {
		dev_err(&client->dev, "regmap initialization failed.\n");
		return PTR_ERR(data->regmap);
	}

	data->client = client;
	data->indio_dev = indio_dev;
	mutex_init(&data->lock);

	ret = pm_runtime_set_active(&client->dev);
	if (ret)
		goto error_power_down;

	pm_runtime_enable(&client->dev);
	pm_runtime_set_autosuspend_delay(&client->dev, 5000);
	pm_runtime_use_autosuspend(&client->dev);

	apds9960_set_power_state(data, true);

	ret = apds9960_regfield_init(data);
	if (ret)
		goto error_power_down;

	ret = apds9960_chip_init(data);
	if (ret)
		goto error_power_down;

	if (client->irq <= 0) {
		dev_err(&client->dev, "no valid irq defined\n");
		ret = -EINVAL;
		goto error_power_down;
	}
	ret = devm_request_threaded_irq(&client->dev, client->irq,
					NULL, apds9960_interrupt_handler,
					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
					"apds9960_event",
					indio_dev);
	if (ret) {
		dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
		goto error_power_down;
	}

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

	apds9960_set_power_state(data, false);

	return 0;

error_power_down:
	apds9960_set_power_state(data, false);

	return ret;
}

static int apds9960_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct apds9960_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);
	apds9960_set_powermode(data, 0);

	return 0;
}

#ifdef CONFIG_PM
static int apds9960_runtime_suspend(struct device *dev)
{
	struct apds9960_data *data =
			iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

	return apds9960_set_powermode(data, 0);
}

static int apds9960_runtime_resume(struct device *dev)
{
	struct apds9960_data *data =
			iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

	return apds9960_set_powermode(data, 1);
}
#endif

static const struct dev_pm_ops apds9960_pm_ops = {
	SET_RUNTIME_PM_OPS(apds9960_runtime_suspend,
			   apds9960_runtime_resume, NULL)
};

static const struct i2c_device_id apds9960_id[] = {
	{ "apds9960", 0 },
	{}
};
MODULE_DEVICE_TABLE(i2c, apds9960_id);

static struct i2c_driver apds9960_driver = {
	.driver = {
		.name	= APDS9960_DRV_NAME,
		.pm	= &apds9960_pm_ops,
	},
	.probe		= apds9960_probe,
	.remove		= apds9960_remove,
	.id_table	= apds9960_id,
};
module_i2c_driver(apds9960_driver);

MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
MODULE_DESCRIPTION("ADPS9960 Gesture/RGB/ALS/Proximity sensor");
MODULE_LICENSE("GPL");