// 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_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,
                                      bool 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_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");