// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2021 Joe Sandom <joe.g.sandom@gmail.com>
 *
 * Datasheet: https://ams.com/tsl25911#tab/documents
 *
 * Device driver for the TAOS TSL2591. This is a very-high sensitivity
 * light-to-digital converter that transforms light intensity into a digital
 * signal.
 */

#include <linux/bitfield.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pm_runtime.h>
#include <linux/sysfs.h>

#include <linux/unaligned.h>

#include <linux/iio/events.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

/* ADC integration time, field value to time in ms */
#define TSL2591_FVAL_TO_MSEC(x) (((x) + 1) * 100)
/* ADC integration time, field value to time in seconds */
#define TSL2591_FVAL_TO_SEC(x) ((x) + 1)
/* ADC integration time, time in seconds to field value */
#define TSL2591_SEC_TO_FVAL(x) ((x) - 1)

/* TSL2591 register set */
#define TSL2591_ENABLE      0x00
#define TSL2591_CONTROL     0x01
#define TSL2591_AILTL       0x04
#define TSL2591_AILTH       0x05
#define TSL2591_AIHTL       0x06
#define TSL2591_AIHTH       0x07
#define TSL2591_NP_AILTL    0x08
#define TSL2591_NP_AILTH    0x09
#define TSL2591_NP_AIHTL    0x0A
#define TSL2591_NP_AIHTH    0x0B
#define TSL2591_PERSIST     0x0C
#define TSL2591_PACKAGE_ID  0x11
#define TSL2591_DEVICE_ID   0x12
#define TSL2591_STATUS      0x13
#define TSL2591_C0_DATAL    0x14
#define TSL2591_C0_DATAH    0x15
#define TSL2591_C1_DATAL    0x16
#define TSL2591_C1_DATAH    0x17

/* TSL2591 command register definitions */
#define TSL2591_CMD_NOP             0xA0
#define TSL2591_CMD_SF_INTSET       0xE4
#define TSL2591_CMD_SF_CALS_I       0xE5
#define TSL2591_CMD_SF_CALS_NPI     0xE7
#define TSL2591_CMD_SF_CNP_ALSI     0xEA

/* TSL2591 enable register definitions */
#define TSL2591_PWR_ON              0x01
#define TSL2591_PWR_OFF             0x00
#define TSL2591_ENABLE_ALS          0x02
#define TSL2591_ENABLE_ALS_INT      0x10
#define TSL2591_ENABLE_SLEEP_INT    0x40
#define TSL2591_ENABLE_NP_INT       0x80

/* TSL2591 control register definitions */
#define TSL2591_CTRL_ALS_INTEGRATION_100MS  0x00
#define TSL2591_CTRL_ALS_INTEGRATION_200MS  0x01
#define TSL2591_CTRL_ALS_INTEGRATION_300MS  0x02
#define TSL2591_CTRL_ALS_INTEGRATION_400MS  0x03
#define TSL2591_CTRL_ALS_INTEGRATION_500MS  0x04
#define TSL2591_CTRL_ALS_INTEGRATION_600MS  0x05
#define TSL2591_CTRL_ALS_LOW_GAIN           0x00
#define TSL2591_CTRL_ALS_MED_GAIN           0x10
#define TSL2591_CTRL_ALS_HIGH_GAIN          0x20
#define TSL2591_CTRL_ALS_MAX_GAIN           0x30
#define TSL2591_CTRL_SYS_RESET              0x80

/* TSL2591 persist register definitions */
#define TSL2591_PRST_ALS_INT_CYCLE_0        0x00
#define TSL2591_PRST_ALS_INT_CYCLE_ANY      0x01
#define TSL2591_PRST_ALS_INT_CYCLE_2        0x02
#define TSL2591_PRST_ALS_INT_CYCLE_3        0x03
#define TSL2591_PRST_ALS_INT_CYCLE_5        0x04
#define TSL2591_PRST_ALS_INT_CYCLE_10       0x05
#define TSL2591_PRST_ALS_INT_CYCLE_15       0x06
#define TSL2591_PRST_ALS_INT_CYCLE_20       0x07
#define TSL2591_PRST_ALS_INT_CYCLE_25       0x08
#define TSL2591_PRST_ALS_INT_CYCLE_30       0x09
#define TSL2591_PRST_ALS_INT_CYCLE_35       0x0A
#define TSL2591_PRST_ALS_INT_CYCLE_40       0x0B
#define TSL2591_PRST_ALS_INT_CYCLE_45       0x0C
#define TSL2591_PRST_ALS_INT_CYCLE_50       0x0D
#define TSL2591_PRST_ALS_INT_CYCLE_55       0x0E
#define TSL2591_PRST_ALS_INT_CYCLE_60       0x0F
#define TSL2591_PRST_ALS_INT_CYCLE_MAX      (BIT(4) - 1)

/* TSL2591 PID register mask */
#define TSL2591_PACKAGE_ID_MASK  GENMASK(5, 4)

/* TSL2591 ID register mask */
#define TSL2591_DEVICE_ID_MASK   GENMASK(7, 0)

/* TSL2591 status register masks */
#define TSL2591_STS_ALS_VALID_MASK   BIT(0)
#define TSL2591_STS_ALS_INT_MASK     BIT(4)
#define TSL2591_STS_NPERS_INT_MASK   BIT(5)
#define TSL2591_STS_VAL_HIGH_MASK    BIT(0)

/* TSL2591 constant values */
#define TSL2591_PACKAGE_ID_VAL  0x00
#define TSL2591_DEVICE_ID_VAL   0x50

/* Power off suspend delay time MS */
#define TSL2591_POWER_OFF_DELAY_MS   2000

/* TSL2591 default values */
#define TSL2591_DEFAULT_ALS_INT_TIME          TSL2591_CTRL_ALS_INTEGRATION_300MS
#define TSL2591_DEFAULT_ALS_GAIN              TSL2591_CTRL_ALS_MED_GAIN
#define TSL2591_DEFAULT_ALS_PERSIST           TSL2591_PRST_ALS_INT_CYCLE_ANY
#define TSL2591_DEFAULT_ALS_LOWER_THRESH      100
#define TSL2591_DEFAULT_ALS_UPPER_THRESH      1500

/* TSL2591 number of data registers */
#define TSL2591_NUM_DATA_REGISTERS     4

/* TSL2591 number of valid status reads on ADC complete */
#define TSL2591_ALS_STS_VALID_COUNT    10

/* TSL2591 delay period between polls when checking for ALS valid flag */
#define TSL2591_DELAY_PERIOD_US        10000

/* TSL2591 maximum values */
#define TSL2591_MAX_ALS_INT_TIME_MS    600
#define TSL2591_ALS_MAX_VALUE	       (BIT(16) - 1)

/*
 * LUX calculations;
 * AGAIN values from Adafruit's TSL2591 Arduino library
 * https://github.com/adafruit/Adafruit_TSL2591_Library
 */
#define TSL2591_CTRL_ALS_LOW_GAIN_MULTIPLIER   1
#define TSL2591_CTRL_ALS_MED_GAIN_MULTIPLIER   25
#define TSL2591_CTRL_ALS_HIGH_GAIN_MULTIPLIER  428
#define TSL2591_CTRL_ALS_MAX_GAIN_MULTIPLIER   9876
#define TSL2591_LUX_COEFFICIENT                408

struct tsl2591_als_settings {
	u16 als_lower_thresh;
	u16 als_upper_thresh;
	u8 als_int_time;
	u8 als_persist;
	u8 als_gain;
};

struct tsl2591_chip {
	struct tsl2591_als_settings als_settings;
	struct i2c_client *client;
	/*
	 * Keep als_settings in sync with hardware state
	 * and ensure multiple readers are serialized.
	 */
	struct mutex als_mutex;
	bool events_enabled;
};

/*
 * Period table is ALS persist cycle x integration time setting
 * Integration times: 100ms, 200ms, 300ms, 400ms, 500ms, 600ms
 * ALS cycles: 1, 2, 3, 5, 10, 20, 25, 30, 35, 40, 45, 50, 55, 60
 */
static const char * const tsl2591_als_period_list[] = {
	"0.1 0.2 0.3 0.5 1.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0",
	"0.2 0.4 0.6 1.0 2.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0",
	"0.3 0.6 0.9 1.5 3.0 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0",
	"0.4 0.8 1.2 2.0 4.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0",
	"0.5 1.0 1.5 2.5 5.0 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0",
	"0.6 1.2 1.8 3.0 6.0 12.0 15.0 18.0 21.0 24.0 27.0 30.0 33.0 36.0",
};

static const int tsl2591_int_time_available[] = {
	1, 2, 3, 4, 5, 6,
};

static const int tsl2591_calibscale_available[] = {
	1, 25, 428, 9876,
};

static int tsl2591_set_als_lower_threshold(struct tsl2591_chip *chip,
					   u16 als_lower_threshold);
static int tsl2591_set_als_upper_threshold(struct tsl2591_chip *chip,
					   u16 als_upper_threshold);

static int tsl2591_gain_to_multiplier(const u8 als_gain)
{
	switch (als_gain) {
	case TSL2591_CTRL_ALS_LOW_GAIN:
		return TSL2591_CTRL_ALS_LOW_GAIN_MULTIPLIER;
	case TSL2591_CTRL_ALS_MED_GAIN:
		return TSL2591_CTRL_ALS_MED_GAIN_MULTIPLIER;
	case TSL2591_CTRL_ALS_HIGH_GAIN:
		return TSL2591_CTRL_ALS_HIGH_GAIN_MULTIPLIER;
	case TSL2591_CTRL_ALS_MAX_GAIN:
		return TSL2591_CTRL_ALS_MAX_GAIN_MULTIPLIER;
	default:
		return -EINVAL;
	}
}

static int tsl2591_multiplier_to_gain(const u32 multiplier)
{
	switch (multiplier) {
	case TSL2591_CTRL_ALS_LOW_GAIN_MULTIPLIER:
		return TSL2591_CTRL_ALS_LOW_GAIN;
	case TSL2591_CTRL_ALS_MED_GAIN_MULTIPLIER:
		return TSL2591_CTRL_ALS_MED_GAIN;
	case TSL2591_CTRL_ALS_HIGH_GAIN_MULTIPLIER:
		return TSL2591_CTRL_ALS_HIGH_GAIN;
	case TSL2591_CTRL_ALS_MAX_GAIN_MULTIPLIER:
		return TSL2591_CTRL_ALS_MAX_GAIN;
	default:
		return -EINVAL;
	}
}

static int tsl2591_persist_cycle_to_lit(const u8 als_persist)
{
	switch (als_persist) {
	case TSL2591_PRST_ALS_INT_CYCLE_ANY:
		return 1;
	case TSL2591_PRST_ALS_INT_CYCLE_2:
		return 2;
	case TSL2591_PRST_ALS_INT_CYCLE_3:
		return 3;
	case TSL2591_PRST_ALS_INT_CYCLE_5:
		return 5;
	case TSL2591_PRST_ALS_INT_CYCLE_10:
		return 10;
	case TSL2591_PRST_ALS_INT_CYCLE_15:
		return 15;
	case TSL2591_PRST_ALS_INT_CYCLE_20:
		return 20;
	case TSL2591_PRST_ALS_INT_CYCLE_25:
		return 25;
	case TSL2591_PRST_ALS_INT_CYCLE_30:
		return 30;
	case TSL2591_PRST_ALS_INT_CYCLE_35:
		return 35;
	case TSL2591_PRST_ALS_INT_CYCLE_40:
		return 40;
	case TSL2591_PRST_ALS_INT_CYCLE_45:
		return 45;
	case TSL2591_PRST_ALS_INT_CYCLE_50:
		return 50;
	case TSL2591_PRST_ALS_INT_CYCLE_55:
		return 55;
	case TSL2591_PRST_ALS_INT_CYCLE_60:
		return 60;
	default:
		return -EINVAL;
	}
}

static int tsl2591_persist_lit_to_cycle(const u8 als_persist)
{
	switch (als_persist) {
	case 1:
		return TSL2591_PRST_ALS_INT_CYCLE_ANY;
	case 2:
		return TSL2591_PRST_ALS_INT_CYCLE_2;
	case 3:
		return TSL2591_PRST_ALS_INT_CYCLE_3;
	case 5:
		return TSL2591_PRST_ALS_INT_CYCLE_5;
	case 10:
		return TSL2591_PRST_ALS_INT_CYCLE_10;
	case 15:
		return TSL2591_PRST_ALS_INT_CYCLE_15;
	case 20:
		return TSL2591_PRST_ALS_INT_CYCLE_20;
	case 25:
		return TSL2591_PRST_ALS_INT_CYCLE_25;
	case 30:
		return TSL2591_PRST_ALS_INT_CYCLE_30;
	case 35:
		return TSL2591_PRST_ALS_INT_CYCLE_35;
	case 40:
		return TSL2591_PRST_ALS_INT_CYCLE_40;
	case 45:
		return TSL2591_PRST_ALS_INT_CYCLE_45;
	case 50:
		return TSL2591_PRST_ALS_INT_CYCLE_50;
	case 55:
		return TSL2591_PRST_ALS_INT_CYCLE_55;
	case 60:
		return TSL2591_PRST_ALS_INT_CYCLE_60;
	default:
		return -EINVAL;
	}
}

static int tsl2591_compatible_int_time(struct tsl2591_chip *chip,
				       const u32 als_integration_time)
{
	switch (als_integration_time) {
	case TSL2591_CTRL_ALS_INTEGRATION_100MS:
	case TSL2591_CTRL_ALS_INTEGRATION_200MS:
	case TSL2591_CTRL_ALS_INTEGRATION_300MS:
	case TSL2591_CTRL_ALS_INTEGRATION_400MS:
	case TSL2591_CTRL_ALS_INTEGRATION_500MS:
	case TSL2591_CTRL_ALS_INTEGRATION_600MS:
		return 0;
	default:
		return -EINVAL;
	}
}

static int tsl2591_als_time_to_fval(const u32 als_integration_time)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(tsl2591_int_time_available); i++) {
		if (als_integration_time == tsl2591_int_time_available[i])
			return TSL2591_SEC_TO_FVAL(als_integration_time);
	}

	return -EINVAL;
}

static int tsl2591_compatible_gain(struct tsl2591_chip *chip, const u8 als_gain)
{
	switch (als_gain) {
	case TSL2591_CTRL_ALS_LOW_GAIN:
	case TSL2591_CTRL_ALS_MED_GAIN:
	case TSL2591_CTRL_ALS_HIGH_GAIN:
	case TSL2591_CTRL_ALS_MAX_GAIN:
		return 0;
	default:
		return -EINVAL;
	}
}

static int tsl2591_compatible_als_persist_cycle(struct tsl2591_chip *chip,
						const u32 als_persist)
{
	switch (als_persist) {
	case TSL2591_PRST_ALS_INT_CYCLE_ANY:
	case TSL2591_PRST_ALS_INT_CYCLE_2:
	case TSL2591_PRST_ALS_INT_CYCLE_3:
	case TSL2591_PRST_ALS_INT_CYCLE_5:
	case TSL2591_PRST_ALS_INT_CYCLE_10:
	case TSL2591_PRST_ALS_INT_CYCLE_15:
	case TSL2591_PRST_ALS_INT_CYCLE_20:
	case TSL2591_PRST_ALS_INT_CYCLE_25:
	case TSL2591_PRST_ALS_INT_CYCLE_30:
	case TSL2591_PRST_ALS_INT_CYCLE_35:
	case TSL2591_PRST_ALS_INT_CYCLE_40:
	case TSL2591_PRST_ALS_INT_CYCLE_45:
	case TSL2591_PRST_ALS_INT_CYCLE_50:
	case TSL2591_PRST_ALS_INT_CYCLE_55:
	case TSL2591_PRST_ALS_INT_CYCLE_60:
		return 0;
	default:
		return -EINVAL;
	}
}

static int tsl2591_check_als_valid(struct i2c_client *client)
{
	int ret;

	ret = i2c_smbus_read_byte_data(client, TSL2591_CMD_NOP | TSL2591_STATUS);
	if (ret < 0) {
		dev_err(&client->dev, "Failed to read register\n");
		return -EINVAL;
	}

	return FIELD_GET(TSL2591_STS_ALS_VALID_MASK, ret);
}

static int tsl2591_wait_adc_complete(struct tsl2591_chip *chip)
{
	struct tsl2591_als_settings settings = chip->als_settings;
	struct i2c_client *client = chip->client;
	int delay;
	int val;
	int ret;

	delay = TSL2591_FVAL_TO_MSEC(settings.als_int_time);
	if (!delay)
		return -EINVAL;

	/*
	 * Sleep for ALS integration time to allow enough time or an ADC read
	 * cycle to complete. Check status after delay for ALS valid.
	 */
	msleep(delay);

	/* Check for status ALS valid flag for up to 100ms */
	ret = readx_poll_timeout(tsl2591_check_als_valid, client,
				 val, val == TSL2591_STS_VAL_HIGH_MASK,
				 TSL2591_DELAY_PERIOD_US,
				 TSL2591_DELAY_PERIOD_US * TSL2591_ALS_STS_VALID_COUNT);
	if (ret)
		dev_err(&client->dev, "Timed out waiting for valid ALS data\n");

	return ret;
}

/*
 * tsl2591_read_channel_data - Reads raw channel data and calculates lux
 *
 * Formula for lux calculation;
 * Derived from Adafruit's TSL2591 library
 * Link: https://github.com/adafruit/Adafruit_TSL2591_Library
 * Counts Per Lux (CPL) = (ATIME_ms * AGAIN) / LUX DF
 * lux = ((C0DATA - C1DATA) * (1 - (C1DATA / C0DATA))) / CPL
 *
 * Scale values to get more representative value of lux i.e.
 * lux = ((C0DATA - C1DATA) * (1000 - ((C1DATA * 1000) / C0DATA))) / CPL
 *
 * Channel 0 = IR + Visible
 * Channel 1 = IR only
 */
static int tsl2591_read_channel_data(struct iio_dev *indio_dev,
				     struct iio_chan_spec const *chan,
				     int *val, int *val2)
{
	struct tsl2591_chip *chip = iio_priv(indio_dev);
	struct tsl2591_als_settings *settings = &chip->als_settings;
	struct i2c_client *client = chip->client;
	u8 als_data[TSL2591_NUM_DATA_REGISTERS];
	int counts_per_lux, int_time_fval, gain_multi, lux;
	u16 als_ch0, als_ch1;
	int ret;

	ret = tsl2591_wait_adc_complete(chip);
	if (ret < 0) {
		dev_err(&client->dev, "No data available. Err: %d\n", ret);
		return ret;
	}

	ret = i2c_smbus_read_i2c_block_data(client,
					    TSL2591_CMD_NOP | TSL2591_C0_DATAL,
					    sizeof(als_data), als_data);
	if (ret < 0) {
		dev_err(&client->dev, "Failed to read data bytes");
		return ret;
	}

	als_ch0 = get_unaligned_le16(&als_data[0]);
	als_ch1 = get_unaligned_le16(&als_data[2]);

	switch (chan->type) {
	case IIO_INTENSITY:
		if (chan->channel2 == IIO_MOD_LIGHT_BOTH)
			*val = als_ch0;
		else if (chan->channel2 == IIO_MOD_LIGHT_IR)
			*val = als_ch1;
		else
			return -EINVAL;
		break;
	case IIO_LIGHT:
		gain_multi = tsl2591_gain_to_multiplier(settings->als_gain);
		if (gain_multi < 0) {
			dev_err(&client->dev, "Invalid multiplier");
			return gain_multi;
		}

		int_time_fval = TSL2591_FVAL_TO_MSEC(settings->als_int_time);
		/* Calculate counts per lux value */
		counts_per_lux = (int_time_fval * gain_multi) / TSL2591_LUX_COEFFICIENT;

		dev_dbg(&client->dev, "Counts Per Lux: %d\n", counts_per_lux);

		/* Calculate lux value */
		lux = ((als_ch0 - als_ch1) *
		       (1000 - ((als_ch1 * 1000) / als_ch0))) / counts_per_lux;

		dev_dbg(&client->dev, "Raw lux calculation: %d\n", lux);

		/* Divide by 1000 to get real lux value before scaling */
		*val = lux / 1000;

		/* Get the decimal part of lux reading */
		*val2 = (lux - (*val * 1000)) * 1000;

		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int tsl2591_set_als_gain_int_time(struct tsl2591_chip *chip)
{
	struct tsl2591_als_settings als_settings = chip->als_settings;
	struct i2c_client *client = chip->client;
	int ret;

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_CONTROL,
					als_settings.als_int_time | als_settings.als_gain);
	if (ret)
		dev_err(&client->dev, "Failed to set als gain & int time\n");

	return ret;
}

static int tsl2591_set_als_lower_threshold(struct tsl2591_chip *chip,
					   u16 als_lower_threshold)
{
	struct tsl2591_als_settings als_settings = chip->als_settings;
	struct i2c_client *client = chip->client;
	u16 als_upper_threshold;
	u8 als_lower_l;
	u8 als_lower_h;
	int ret;

	chip->als_settings.als_lower_thresh = als_lower_threshold;

	/*
	 * Lower threshold should not be greater or equal to upper.
	 * If this is the case, then assert upper threshold to new lower
	 * threshold + 1 to avoid ordering issues when setting thresholds.
	 */
	if (als_lower_threshold >= als_settings.als_upper_thresh) {
		als_upper_threshold = als_lower_threshold + 1;
		tsl2591_set_als_upper_threshold(chip, als_upper_threshold);
	}

	als_lower_l = als_lower_threshold;
	als_lower_h = als_lower_threshold >> 8;

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_AILTL,
					als_lower_l);
	if (ret) {
		dev_err(&client->dev, "Failed to set als lower threshold\n");
		return ret;
	}

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_AILTH,
					als_lower_h);
	if (ret) {
		dev_err(&client->dev, "Failed to set als lower threshold\n");
		return ret;
	}

	return 0;
}

static int tsl2591_set_als_upper_threshold(struct tsl2591_chip *chip,
					   u16 als_upper_threshold)
{
	struct tsl2591_als_settings als_settings = chip->als_settings;
	struct i2c_client *client = chip->client;
	u16 als_lower_threshold;
	u8 als_upper_l;
	u8 als_upper_h;
	int ret;

	if (als_upper_threshold > TSL2591_ALS_MAX_VALUE)
		return -EINVAL;

	chip->als_settings.als_upper_thresh = als_upper_threshold;

	/*
	 * Upper threshold should not be less than lower. If this
	 * is the case, then assert lower threshold to new upper
	 * threshold - 1 to avoid ordering issues when setting thresholds.
	 */
	if (als_upper_threshold < als_settings.als_lower_thresh) {
		als_lower_threshold = als_upper_threshold - 1;
		tsl2591_set_als_lower_threshold(chip, als_lower_threshold);
	}

	als_upper_l = als_upper_threshold;
	als_upper_h = als_upper_threshold >> 8;

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_AIHTL,
					als_upper_l);
	if (ret) {
		dev_err(&client->dev, "Failed to set als upper threshold\n");
		return ret;
	}

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_AIHTH,
					als_upper_h);
	if (ret) {
		dev_err(&client->dev, "Failed to set als upper threshold\n");
		return ret;
	}

	return 0;
}

static int tsl2591_set_als_persist_cycle(struct tsl2591_chip *chip,
					 u8 als_persist)
{
	struct i2c_client *client = chip->client;
	int ret;

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_PERSIST,
					als_persist);
	if (ret)
		dev_err(&client->dev, "Failed to set als persist cycle\n");

	chip->als_settings.als_persist = als_persist;

	return ret;
}

static int tsl2591_set_power_state(struct tsl2591_chip *chip, u8 state)
{
	struct i2c_client *client = chip->client;
	int ret;

	ret = i2c_smbus_write_byte_data(client,
					TSL2591_CMD_NOP | TSL2591_ENABLE,
					state);
	if (ret)
		dev_err(&client->dev,
			"Failed to set the power state to %#04x\n", state);

	return ret;
}

static ssize_t tsl2591_in_illuminance_period_available_show(struct device *dev,
							    struct device_attribute *attr,
							    char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct tsl2591_chip *chip = iio_priv(indio_dev);

	return sysfs_emit(buf, "%s\n",
		       tsl2591_als_period_list[chip->als_settings.als_int_time]);
}

static IIO_DEVICE_ATTR_RO(tsl2591_in_illuminance_period_available, 0);

static struct attribute *tsl2591_event_attrs_ctrl[] = {
	&iio_dev_attr_tsl2591_in_illuminance_period_available.dev_attr.attr,
	NULL
};

static const struct attribute_group tsl2591_event_attribute_group = {
	.attrs = tsl2591_event_attrs_ctrl,
};

static const struct iio_event_spec tsl2591_events[] = {
	{
		.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_PERIOD) |
				BIT(IIO_EV_INFO_ENABLE),
	},
};

static const struct iio_chan_spec tsl2591_channels[] = {
	{
		.type = IIO_INTENSITY,
		.modified = 1,
		.channel2 = IIO_MOD_LIGHT_IR,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
						     BIT(IIO_CHAN_INFO_CALIBSCALE),
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
					   BIT(IIO_CHAN_INFO_CALIBSCALE)
	},
	{
		.type = IIO_INTENSITY,
		.modified = 1,
		.channel2 = IIO_MOD_LIGHT_BOTH,
		.event_spec = tsl2591_events,
		.num_event_specs = ARRAY_SIZE(tsl2591_events),
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
						     BIT(IIO_CHAN_INFO_CALIBSCALE),
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
					   BIT(IIO_CHAN_INFO_CALIBSCALE)
	},
	{
		.type = IIO_LIGHT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
						     BIT(IIO_CHAN_INFO_CALIBSCALE),
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
					   BIT(IIO_CHAN_INFO_CALIBSCALE)
	},
};

static int tsl2591_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long mask)
{
	struct tsl2591_chip *chip = iio_priv(indio_dev);
	struct i2c_client *client = chip->client;
	int ret;

	pm_runtime_get_sync(&client->dev);

	mutex_lock(&chip->als_mutex);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (chan->type != IIO_INTENSITY) {
			ret = -EINVAL;
			goto err_unlock;
		}

		ret = tsl2591_read_channel_data(indio_dev, chan, val, val2);
		if (ret < 0)
			goto err_unlock;

		ret = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_PROCESSED:
		if (chan->type != IIO_LIGHT) {
			ret = -EINVAL;
			goto err_unlock;
		}

		ret = tsl2591_read_channel_data(indio_dev, chan, val, val2);
		if (ret < 0)
			break;

		ret = IIO_VAL_INT_PLUS_MICRO;
		break;
	case IIO_CHAN_INFO_INT_TIME:
		if (chan->type != IIO_INTENSITY) {
			ret = -EINVAL;
			goto err_unlock;
		}

		*val = TSL2591_FVAL_TO_SEC(chip->als_settings.als_int_time);
		ret = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_CALIBSCALE:
		if (chan->type != IIO_INTENSITY) {
			ret = -EINVAL;
			goto err_unlock;
		}

		*val = tsl2591_gain_to_multiplier(chip->als_settings.als_gain);
		ret = IIO_VAL_INT;
		break;
	default:
		ret = -EINVAL;
		break;
	}

err_unlock:
	mutex_unlock(&chip->als_mutex);

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

	return ret;
}

static int tsl2591_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct tsl2591_chip *chip = iio_priv(indio_dev);
	int int_time;
	int gain;
	int ret;

	mutex_lock(&chip->als_mutex);

	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
		int_time = tsl2591_als_time_to_fval(val);
		if (int_time < 0) {
			ret = int_time;
			goto err_unlock;
		}
		ret = tsl2591_compatible_int_time(chip, int_time);
		if (ret < 0)
			goto err_unlock;

		chip->als_settings.als_int_time = int_time;
		break;
	case IIO_CHAN_INFO_CALIBSCALE:
		gain = tsl2591_multiplier_to_gain(val);
		if (gain < 0) {
			ret = gain;
			goto err_unlock;
		}
		ret = tsl2591_compatible_gain(chip, gain);
		if (ret < 0)
			goto err_unlock;

		chip->als_settings.als_gain = gain;
		break;
	default:
		ret = -EINVAL;
		goto err_unlock;
	}

	ret = tsl2591_set_als_gain_int_time(chip);

err_unlock:
	mutex_unlock(&chip->als_mutex);
	return ret;
}

static int tsl2591_read_available(struct iio_dev *indio_dev,
				  struct iio_chan_spec const *chan,
				  const int **vals, int *type, int *length,
				  long mask)
{
	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
		*length = ARRAY_SIZE(tsl2591_int_time_available);
		*vals = tsl2591_int_time_available;
		*type = IIO_VAL_INT;
		return IIO_AVAIL_LIST;

	case IIO_CHAN_INFO_CALIBSCALE:
		*length = ARRAY_SIZE(tsl2591_calibscale_available);
		*vals = tsl2591_calibscale_available;
		*type = IIO_VAL_INT;
		return IIO_AVAIL_LIST;
	default:
		return -EINVAL;
	}
}

static int tsl2591_read_event_value(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 tsl2591_chip *chip = iio_priv(indio_dev);
	struct i2c_client *client = chip->client;
	int als_persist, int_time, period;
	int ret;

	mutex_lock(&chip->als_mutex);

	switch (info) {
	case IIO_EV_INFO_VALUE:
		switch (dir) {
		case IIO_EV_DIR_RISING:
			*val = chip->als_settings.als_upper_thresh;
			break;
		case IIO_EV_DIR_FALLING:
			*val = chip->als_settings.als_lower_thresh;
			break;
		default:
			ret = -EINVAL;
			goto err_unlock;
		}
		ret = IIO_VAL_INT;
		break;
	case IIO_EV_INFO_PERIOD:
		ret = i2c_smbus_read_byte_data(client,
					       TSL2591_CMD_NOP | TSL2591_PERSIST);
		if (ret <= 0 || ret > TSL2591_PRST_ALS_INT_CYCLE_MAX)
			goto err_unlock;

		als_persist = tsl2591_persist_cycle_to_lit(ret);
		int_time = TSL2591_FVAL_TO_MSEC(chip->als_settings.als_int_time);
		period = als_persist * (int_time * MSEC_PER_SEC);

		*val = period / USEC_PER_SEC;
		*val2 = period % USEC_PER_SEC;

		ret = IIO_VAL_INT_PLUS_MICRO;
		break;
	default:
		ret = -EINVAL;
		break;
	}

err_unlock:
	mutex_unlock(&chip->als_mutex);
	return ret;
}

static int tsl2591_write_event_value(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 tsl2591_chip *chip = iio_priv(indio_dev);
	int period, int_time, als_persist;
	int ret;

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

	mutex_lock(&chip->als_mutex);

	switch (info) {
	case IIO_EV_INFO_VALUE:
		if (val > TSL2591_ALS_MAX_VALUE) {
			ret = -EINVAL;
			goto err_unlock;
		}

		switch (dir) {
		case IIO_EV_DIR_RISING:
			ret = tsl2591_set_als_upper_threshold(chip, val);
			if (ret < 0)
				goto err_unlock;
			break;
		case IIO_EV_DIR_FALLING:
			ret = tsl2591_set_als_lower_threshold(chip, val);
			if (ret < 0)
				goto err_unlock;
			break;
		default:
			ret = -EINVAL;
			goto err_unlock;
		}
		break;
	case IIO_EV_INFO_PERIOD:
		int_time = TSL2591_FVAL_TO_MSEC(chip->als_settings.als_int_time);

		period = ((val * MSEC_PER_SEC) +
			 (val2 / MSEC_PER_SEC)) / int_time;

		als_persist = tsl2591_persist_lit_to_cycle(period);
		if (als_persist < 0) {
			ret = -EINVAL;
			goto err_unlock;
		}

		ret = tsl2591_compatible_als_persist_cycle(chip, als_persist);
		if (ret < 0)
			goto err_unlock;

		ret = tsl2591_set_als_persist_cycle(chip, als_persist);
		if (ret < 0)
			goto err_unlock;
		break;
	default:
		ret = -EINVAL;
		break;
	}

err_unlock:
	mutex_unlock(&chip->als_mutex);
	return ret;
}

static int tsl2591_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 tsl2591_chip *chip = iio_priv(indio_dev);

	return chip->events_enabled;
}

static int tsl2591_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 tsl2591_chip *chip = iio_priv(indio_dev);
	struct i2c_client *client = chip->client;

	if (state && !chip->events_enabled) {
		chip->events_enabled = true;
		pm_runtime_get_sync(&client->dev);
	} else if (!state && chip->events_enabled) {
		chip->events_enabled = false;
		pm_runtime_mark_last_busy(&client->dev);
		pm_runtime_put_autosuspend(&client->dev);
	}

	return 0;
}

static const struct iio_info tsl2591_info = {
	.event_attrs = &tsl2591_event_attribute_group,
	.read_raw = tsl2591_read_raw,
	.write_raw = tsl2591_write_raw,
	.read_avail = tsl2591_read_available,
	.read_event_value = tsl2591_read_event_value,
	.write_event_value = tsl2591_write_event_value,
	.read_event_config = tsl2591_read_event_config,
	.write_event_config = tsl2591_write_event_config,
};

static const struct iio_info tsl2591_info_no_irq = {
	.read_raw = tsl2591_read_raw,
	.write_raw = tsl2591_write_raw,
	.read_avail = tsl2591_read_available,
};

static int tsl2591_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tsl2591_chip *chip = iio_priv(indio_dev);
	int ret;

	mutex_lock(&chip->als_mutex);
	ret = tsl2591_set_power_state(chip, TSL2591_PWR_OFF);
	mutex_unlock(&chip->als_mutex);

	return ret;
}

static int tsl2591_resume(struct device *dev)
{
	int power_state = TSL2591_PWR_ON | TSL2591_ENABLE_ALS;
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tsl2591_chip *chip = iio_priv(indio_dev);
	int ret;

	if (chip->events_enabled)
		power_state |= TSL2591_ENABLE_ALS_INT;

	mutex_lock(&chip->als_mutex);
	ret = tsl2591_set_power_state(chip, power_state);
	mutex_unlock(&chip->als_mutex);

	return ret;
}

static DEFINE_RUNTIME_DEV_PM_OPS(tsl2591_pm_ops, tsl2591_suspend,
				 tsl2591_resume, NULL);

static irqreturn_t tsl2591_event_handler(int irq, void *private)
{
	struct iio_dev *dev_info = private;
	struct tsl2591_chip *chip = iio_priv(dev_info);
	struct i2c_client *client = chip->client;

	if (!chip->events_enabled)
		return IRQ_NONE;

	iio_push_event(dev_info,
		       IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
					    IIO_EV_TYPE_THRESH,
					    IIO_EV_DIR_EITHER),
					    iio_get_time_ns(dev_info));

	/* Clear ALS irq */
	i2c_smbus_write_byte(client, TSL2591_CMD_SF_CALS_NPI);

	return IRQ_HANDLED;
}

static int tsl2591_load_defaults(struct tsl2591_chip *chip)
{
	int ret;

	chip->als_settings.als_int_time = TSL2591_DEFAULT_ALS_INT_TIME;
	chip->als_settings.als_gain = TSL2591_DEFAULT_ALS_GAIN;
	chip->als_settings.als_lower_thresh = TSL2591_DEFAULT_ALS_LOWER_THRESH;
	chip->als_settings.als_upper_thresh = TSL2591_DEFAULT_ALS_UPPER_THRESH;

	ret = tsl2591_set_als_gain_int_time(chip);
	if (ret < 0)
		return ret;

	ret = tsl2591_set_als_persist_cycle(chip, TSL2591_DEFAULT_ALS_PERSIST);
	if (ret < 0)
		return ret;

	ret = tsl2591_set_als_lower_threshold(chip, TSL2591_DEFAULT_ALS_LOWER_THRESH);
	if (ret < 0)
		return ret;

	ret = tsl2591_set_als_upper_threshold(chip, TSL2591_DEFAULT_ALS_UPPER_THRESH);
	if (ret < 0)
		return ret;

	return 0;
}

static void tsl2591_chip_off(void *data)
{
	struct iio_dev *indio_dev = data;
	struct tsl2591_chip *chip = iio_priv(indio_dev);
	struct i2c_client *client = chip->client;

	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);
	pm_runtime_put_noidle(&client->dev);

	tsl2591_set_power_state(chip, TSL2591_PWR_OFF);
}

static int tsl2591_probe(struct i2c_client *client)
{
	struct tsl2591_chip *chip;
	struct iio_dev *indio_dev;
	int ret;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
		dev_err(&client->dev,
			"I2C smbus byte data functionality is not supported\n");
		return -EOPNOTSUPP;
	}

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

	chip = iio_priv(indio_dev);
	chip->client = client;
	i2c_set_clientdata(client, indio_dev);

	if (client->irq) {
		ret = devm_request_threaded_irq(&client->dev, client->irq,
						NULL, tsl2591_event_handler,
						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
						"tsl2591_irq", indio_dev);
		if (ret) {
			dev_err_probe(&client->dev, ret, "IRQ request error\n");
			return -EINVAL;
		}
		indio_dev->info = &tsl2591_info;
	} else {
		indio_dev->info = &tsl2591_info_no_irq;
	}

	mutex_init(&chip->als_mutex);

	ret = i2c_smbus_read_byte_data(client,
				       TSL2591_CMD_NOP | TSL2591_DEVICE_ID);
	if (ret < 0) {
		dev_err(&client->dev,
			"Failed to read the device ID register\n");
		return ret;
	}
	ret = FIELD_GET(TSL2591_DEVICE_ID_MASK, ret);
	if (ret != TSL2591_DEVICE_ID_VAL) {
		dev_err(&client->dev, "Device ID: %#04x unknown\n", ret);
		return -EINVAL;
	}

	indio_dev->channels = tsl2591_channels;
	indio_dev->num_channels = ARRAY_SIZE(tsl2591_channels);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->name = chip->client->name;
	chip->events_enabled = false;

	pm_runtime_enable(&client->dev);
	pm_runtime_set_autosuspend_delay(&client->dev,
					 TSL2591_POWER_OFF_DELAY_MS);
	pm_runtime_use_autosuspend(&client->dev);

	/*
	 * Add chip off to automatically managed path and disable runtime
	 * power management. This ensures that the chip power management
	 * is handled correctly on driver remove. tsl2591_chip_off() must be
	 * added to the managed path after pm runtime is enabled and before
	 * any error exit paths are met to ensure we're not left in a state
	 * of pm runtime not being disabled properly.
	 */
	ret = devm_add_action_or_reset(&client->dev, tsl2591_chip_off,
				       indio_dev);
	if (ret < 0)
		return -EINVAL;

	ret = tsl2591_load_defaults(chip);
	if (ret < 0) {
		dev_err(&client->dev, "Failed to load sensor defaults\n");
		return -EINVAL;
	}

	ret = i2c_smbus_write_byte(client, TSL2591_CMD_SF_CALS_NPI);
	if (ret < 0) {
		dev_err(&client->dev, "Failed to clear als irq\n");
		return -EINVAL;
	}

	return devm_iio_device_register(&client->dev, indio_dev);
}

static const struct of_device_id tsl2591_of_match[] = {
	{ .compatible = "amstaos,tsl2591"},
	{}
};
MODULE_DEVICE_TABLE(of, tsl2591_of_match);

static struct i2c_driver tsl2591_driver = {
	.driver = {
		.name = "tsl2591",
		.pm = pm_ptr(&tsl2591_pm_ops),
		.of_match_table = tsl2591_of_match,
	},
	.probe = tsl2591_probe
};
module_i2c_driver(tsl2591_driver);

MODULE_AUTHOR("Joe Sandom <joe.g.sandom@gmail.com>");
MODULE_DESCRIPTION("TAOS tsl2591 ambient light sensor driver");
MODULE_LICENSE("GPL");