// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Device driver for monitoring ambient light intensity (lux)
 * within the TAOS tsl258x family of devices (tsl2580, tsl2581, tsl2583).
 *
 * Copyright (c) 2011, TAOS Corporation.
 * Copyright (c) 2016-2017 Brian Masney <masneyb@onstation.org>
 */

#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/pm_runtime.h>

/* Device Registers and Masks */
#define TSL2583_CNTRL                   0x00
#define TSL2583_ALS_TIME                0X01
#define TSL2583_INTERRUPT               0x02
#define TSL2583_GAIN                    0x07
#define TSL2583_REVID                   0x11
#define TSL2583_CHIPID                  0x12
#define TSL2583_ALS_CHAN0LO             0x14
#define TSL2583_ALS_CHAN0HI             0x15
#define TSL2583_ALS_CHAN1LO             0x16
#define TSL2583_ALS_CHAN1HI             0x17
#define TSL2583_TMR_LO                  0x18
#define TSL2583_TMR_HI                  0x19

/* tsl2583 cmd reg masks */
#define TSL2583_CMD_REG                 0x80
#define TSL2583_CMD_SPL_FN              0x60
#define TSL2583_CMD_ALS_INT_CLR         0x01

/* tsl2583 cntrl reg masks */
#define TSL2583_CNTL_ADC_ENBL           0x02
#define TSL2583_CNTL_PWR_OFF            0x00
#define TSL2583_CNTL_PWR_ON             0x01

/* tsl2583 status reg masks */
#define TSL2583_STA_ADC_VALID           0x01
#define TSL2583_STA_ADC_INTR            0x10

/* Lux calculation constants */
#define TSL2583_LUX_CALC_OVER_FLOW      65535

#define TSL2583_INTERRUPT_DISABLED      0x00

#define TSL2583_CHIP_ID                 0x90
#define TSL2583_CHIP_ID_MASK            0xf0

#define TSL2583_POWER_OFF_DELAY_MS      2000

/* Per-device data */
struct tsl2583_als_info {
        u16 als_ch0;
        u16 als_ch1;
        u16 lux;
};

struct tsl2583_lux {
        unsigned int ratio;
        unsigned int ch0;
        unsigned int ch1;
};

static const struct tsl2583_lux tsl2583_default_lux[] = {
        {  9830,  8520, 15729 },
        { 12452, 10807, 23344 },
        { 14746,  6383, 11705 },
        { 17695,  4063,  6554 },
        {     0,     0,     0 }  /* Termination segment */
};

#define TSL2583_MAX_LUX_TABLE_ENTRIES 11

struct tsl2583_settings {
        int als_time;
        int als_gain;
        int als_gain_trim;
        int als_cal_target;

        /*
         * This structure is intentionally large to accommodate updates via
         * sysfs. Sized to 11 = max 10 segments + 1 termination segment.
         * Assumption is that one and only one type of glass used.
         */
        struct tsl2583_lux als_device_lux[TSL2583_MAX_LUX_TABLE_ENTRIES];
};

struct tsl2583_chip {
        struct mutex als_mutex;
        struct i2c_client *client;
        struct tsl2583_als_info als_cur_info;
        struct tsl2583_settings als_settings;
        int als_time_scale;
        int als_saturation;
};

struct gainadj {
        s16 ch0;
        s16 ch1;
        s16 mean;
};

/* Index = (0 - 3) Used to validate the gain selection index */
static const struct gainadj gainadj[] = {
        { 1, 1, 1 },
        { 8, 8, 8 },
        { 16, 16, 16 },
        { 107, 115, 111 }
};

/*
 * Provides initial operational parameter defaults.
 * These defaults may be changed through the device's sysfs files.
 */
static void tsl2583_defaults(struct tsl2583_chip *chip)
{
        /*
         * The integration time must be a multiple of 50ms and within the
         * range [50, 600] ms.
         */
        chip->als_settings.als_time = 100;

        /*
         * This is an index into the gainadj table. Assume clear glass as the
         * default.
         */
        chip->als_settings.als_gain = 0;

        /* Default gain trim to account for aperture effects */
        chip->als_settings.als_gain_trim = 1000;

        /* Known external ALS reading used for calibration */
        chip->als_settings.als_cal_target = 130;

        /* Default lux table. */
        memcpy(chip->als_settings.als_device_lux, tsl2583_default_lux,
               sizeof(tsl2583_default_lux));
}

/*
 * Reads and calculates current lux value.
 * The raw ch0 and ch1 values of the ambient light sensed in the last
 * integration cycle are read from the device.
 * Time scale factor array values are adjusted based on the integration time.
 * The raw values are multiplied by a scale factor, and device gain is obtained
 * using gain index. Limit checks are done next, then the ratio of a multiple
 * of ch1 value, to the ch0 value, is calculated. The array als_device_lux[]
 * declared above is then scanned to find the first ratio value that is just
 * above the ratio we just calculated. The ch0 and ch1 multiplier constants in
 * the array are then used along with the time scale factor array values, to
 * calculate the lux.
 */
static int tsl2583_get_lux(struct iio_dev *indio_dev)
{
        u16 ch0, ch1; /* separated ch0/ch1 data from device */
        u32 lux; /* raw lux calculated from device data */
        u64 lux64;
        u32 ratio;
        u8 buf[5];
        struct tsl2583_lux *p;
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int i, ret;

        ret = i2c_smbus_read_byte_data(chip->client, TSL2583_CMD_REG);
        if (ret < 0) {
                dev_err(&chip->client->dev, "%s: failed to read CMD_REG register\n",
                        __func__);
                goto done;
        }

        /* is data new & valid */
        if (!(ret & TSL2583_STA_ADC_INTR)) {
                dev_err(&chip->client->dev, "%s: data not valid; returning last value\n",
                        __func__);
                ret = chip->als_cur_info.lux; /* return LAST VALUE */
                goto done;
        }

        for (i = 0; i < 4; i++) {
                int reg = TSL2583_CMD_REG | (TSL2583_ALS_CHAN0LO + i);

                ret = i2c_smbus_read_byte_data(chip->client, reg);
                if (ret < 0) {
                        dev_err(&chip->client->dev, "%s: failed to read register %x\n",
                                __func__, reg);
                        goto done;
                }
                buf[i] = ret;
        }

        /*
         * Clear the pending interrupt status bit on the chip to allow the next
         * integration cycle to start. This has to be done even though this
         * driver currently does not support interrupts.
         */
        ret = i2c_smbus_write_byte(chip->client,
                                   (TSL2583_CMD_REG | TSL2583_CMD_SPL_FN |
                                    TSL2583_CMD_ALS_INT_CLR));
        if (ret < 0) {
                dev_err(&chip->client->dev, "%s: failed to clear the interrupt bit\n",
                        __func__);
                goto done; /* have no data, so return failure */
        }

        /* extract ALS/lux data */
        ch0 = le16_to_cpup((const __le16 *)&buf[0]);
        ch1 = le16_to_cpup((const __le16 *)&buf[2]);

        chip->als_cur_info.als_ch0 = ch0;
        chip->als_cur_info.als_ch1 = ch1;

        if ((ch0 >= chip->als_saturation) || (ch1 >= chip->als_saturation))
                goto return_max;

        if (!ch0) {
                /*
                 * The sensor appears to be in total darkness so set the
                 * calculated lux to 0 and return early to avoid a division by
                 * zero below when calculating the ratio.
                 */
                ret = 0;
                chip->als_cur_info.lux = 0;
                goto done;
        }

        /* calculate ratio */
        ratio = (ch1 << 15) / ch0;

        /* convert to unscaled lux using the pointer to the table */
        for (p = (struct tsl2583_lux *)chip->als_settings.als_device_lux;
             p->ratio != 0 && p->ratio < ratio; p++)
                ;

        if (p->ratio == 0) {
                lux = 0;
        } else {
                u32 ch0lux, ch1lux;

                ch0lux = ((ch0 * p->ch0) +
                          (gainadj[chip->als_settings.als_gain].ch0 >> 1))
                         / gainadj[chip->als_settings.als_gain].ch0;
                ch1lux = ((ch1 * p->ch1) +
                          (gainadj[chip->als_settings.als_gain].ch1 >> 1))
                         / gainadj[chip->als_settings.als_gain].ch1;

                /* note: lux is 31 bit max at this point */
                if (ch1lux > ch0lux) {
                        dev_dbg(&chip->client->dev, "%s: No Data - Returning 0\n",
                                __func__);
                        ret = 0;
                        chip->als_cur_info.lux = 0;
                        goto done;
                }

                lux = ch0lux - ch1lux;
        }

        /* adjust for active time scale */
        if (chip->als_time_scale == 0)
                lux = 0;
        else
                lux = (lux + (chip->als_time_scale >> 1)) /
                        chip->als_time_scale;

        /*
         * Adjust for active gain scale.
         * The tsl2583_default_lux tables above have a factor of 8192 built in,
         * so we need to shift right.
         * User-specified gain provides a multiplier.
         * Apply user-specified gain before shifting right to retain precision.
         * Use 64 bits to avoid overflow on multiplication.
         * Then go back to 32 bits before division to avoid using div_u64().
         */
        lux64 = lux;
        lux64 = lux64 * chip->als_settings.als_gain_trim;
        lux64 >>= 13;
        lux = lux64;
        lux = (lux + 500) / 1000;

        if (lux > TSL2583_LUX_CALC_OVER_FLOW) { /* check for overflow */
return_max:
                lux = TSL2583_LUX_CALC_OVER_FLOW;
        }

        /* Update the structure with the latest VALID lux. */
        chip->als_cur_info.lux = lux;
        ret = lux;

done:
        return ret;
}

/*
 * Obtain single reading and calculate the als_gain_trim (later used
 * to derive actual lux).
 * Return updated gain_trim value.
 */
static int tsl2583_als_calibrate(struct iio_dev *indio_dev)
{
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        unsigned int gain_trim_val;
        int ret;
        int lux_val;

        ret = i2c_smbus_read_byte_data(chip->client,
                                       TSL2583_CMD_REG | TSL2583_CNTRL);
        if (ret < 0) {
                dev_err(&chip->client->dev,
                        "%s: failed to read from the CNTRL register\n",
                        __func__);
                return ret;
        }

        if ((ret & (TSL2583_CNTL_ADC_ENBL | TSL2583_CNTL_PWR_ON))
                        != (TSL2583_CNTL_ADC_ENBL | TSL2583_CNTL_PWR_ON)) {
                dev_err(&chip->client->dev,
                        "%s: Device is not powered on and/or ADC is not enabled\n",
                        __func__);
                return -EINVAL;
        } else if ((ret & TSL2583_STA_ADC_VALID) != TSL2583_STA_ADC_VALID) {
                dev_err(&chip->client->dev,
                        "%s: The two ADC channels have not completed an integration cycle\n",
                        __func__);
                return -ENODATA;
        }

        lux_val = tsl2583_get_lux(indio_dev);
        if (lux_val < 0) {
                dev_err(&chip->client->dev, "%s: failed to get lux\n",
                        __func__);
                return lux_val;
        }

        gain_trim_val = (unsigned int)(((chip->als_settings.als_cal_target)
                        * chip->als_settings.als_gain_trim) / lux_val);
        if ((gain_trim_val < 250) || (gain_trim_val > 4000)) {
                dev_err(&chip->client->dev,
                        "%s: trim_val of %d is not within the range [250, 4000]\n",
                        __func__, gain_trim_val);
                return -ENODATA;
        }

        chip->als_settings.als_gain_trim = (int)gain_trim_val;

        return 0;
}

static int tsl2583_set_als_time(struct tsl2583_chip *chip)
{
        int als_count, als_time, ret;
        u8 val;

        /* determine als integration register */
        als_count = (chip->als_settings.als_time * 100 + 135) / 270;
        if (!als_count)
                als_count = 1; /* ensure at least one cycle */

        /* convert back to time (encompasses overrides) */
        als_time = (als_count * 27 + 5) / 10;

        val = 256 - als_count;
        ret = i2c_smbus_write_byte_data(chip->client,
                                        TSL2583_CMD_REG | TSL2583_ALS_TIME,
                                        val);
        if (ret < 0) {
                dev_err(&chip->client->dev, "%s: failed to set the als time to %d\n",
                        __func__, val);
                return ret;
        }

        /* set chip struct re scaling and saturation */
        chip->als_saturation = als_count * 922; /* 90% of full scale */
        chip->als_time_scale = (als_time + 25) / 50;

        return ret;
}

static int tsl2583_set_als_gain(struct tsl2583_chip *chip)
{
        int ret;

        /* Set the gain based on als_settings struct */
        ret = i2c_smbus_write_byte_data(chip->client,
                                        TSL2583_CMD_REG | TSL2583_GAIN,
                                        chip->als_settings.als_gain);
        if (ret < 0)
                dev_err(&chip->client->dev,
                        "%s: failed to set the gain to %d\n", __func__,
                        chip->als_settings.als_gain);

        return ret;
}

static int tsl2583_set_power_state(struct tsl2583_chip *chip, u8 state)
{
        int ret;

        ret = i2c_smbus_write_byte_data(chip->client,
                                        TSL2583_CMD_REG | TSL2583_CNTRL, state);
        if (ret < 0)
                dev_err(&chip->client->dev,
                        "%s: failed to set the power state to %d\n", __func__,
                        state);

        return ret;
}

/*
 * Turn the device on.
 * Configuration must be set before calling this function.
 */
static int tsl2583_chip_init_and_power_on(struct iio_dev *indio_dev)
{
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int ret;

        /* Power on the device; ADC off. */
        ret = tsl2583_set_power_state(chip, TSL2583_CNTL_PWR_ON);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_write_byte_data(chip->client,
                                        TSL2583_CMD_REG | TSL2583_INTERRUPT,
                                        TSL2583_INTERRUPT_DISABLED);
        if (ret < 0) {
                dev_err(&chip->client->dev,
                        "%s: failed to disable interrupts\n", __func__);
                return ret;
        }

        ret = tsl2583_set_als_time(chip);
        if (ret < 0)
                return ret;

        ret = tsl2583_set_als_gain(chip);
        if (ret < 0)
                return ret;

        usleep_range(3000, 3500);

        ret = tsl2583_set_power_state(chip, TSL2583_CNTL_PWR_ON |
                                            TSL2583_CNTL_ADC_ENBL);
        if (ret < 0)
                return ret;

        return ret;
}

/* Sysfs Interface Functions */

static ssize_t in_illuminance_input_target_show(struct device *dev,
                                                struct device_attribute *attr,
                                                char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int ret;

        mutex_lock(&chip->als_mutex);
        ret = sprintf(buf, "%d\n", chip->als_settings.als_cal_target);
        mutex_unlock(&chip->als_mutex);

        return ret;
}

static ssize_t in_illuminance_input_target_store(struct device *dev,
                                                 struct device_attribute *attr,
                                                 const char *buf, size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int value;

        if (kstrtoint(buf, 0, &value) || !value)
                return -EINVAL;

        mutex_lock(&chip->als_mutex);
        chip->als_settings.als_cal_target = value;
        mutex_unlock(&chip->als_mutex);

        return len;
}

static ssize_t in_illuminance_calibrate_store(struct device *dev,
                                              struct device_attribute *attr,
                                              const char *buf, size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int value, ret;

        if (kstrtoint(buf, 0, &value) || value != 1)
                return -EINVAL;

        mutex_lock(&chip->als_mutex);

        ret = tsl2583_als_calibrate(indio_dev);
        if (ret < 0)
                goto done;

        ret = len;
done:
        mutex_unlock(&chip->als_mutex);

        return ret;
}

static ssize_t in_illuminance_lux_table_show(struct device *dev,
                                             struct device_attribute *attr,
                                             char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        unsigned int i;
        int offset = 0;

        for (i = 0; i < ARRAY_SIZE(chip->als_settings.als_device_lux); i++) {
                offset += sprintf(buf + offset, "%u,%u,%u,",
                                  chip->als_settings.als_device_lux[i].ratio,
                                  chip->als_settings.als_device_lux[i].ch0,
                                  chip->als_settings.als_device_lux[i].ch1);
                if (chip->als_settings.als_device_lux[i].ratio == 0) {
                        /*
                         * We just printed the first "0" entry.
                         * Now get rid of the extra "," and break.
                         */
                        offset--;
                        break;
                }
        }

        offset += sprintf(buf + offset, "\n");

        return offset;
}

static ssize_t in_illuminance_lux_table_store(struct device *dev,
                                              struct device_attribute *attr,
                                              const char *buf, size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        const unsigned int max_ints = TSL2583_MAX_LUX_TABLE_ENTRIES * 3;
        int value[TSL2583_MAX_LUX_TABLE_ENTRIES * 3 + 1];
        int ret = -EINVAL;
        unsigned int n;

        mutex_lock(&chip->als_mutex);

        get_options(buf, ARRAY_SIZE(value), value);

        /*
         * We now have an array of ints starting at value[1], and
         * enumerated by value[0].
         * We expect each group of three ints is one table entry,
         * and the last table entry is all 0.
         */
        n = value[0];
        if ((n % 3) || n < 6 || n > max_ints) {
                dev_err(dev,
                        "%s: The number of entries in the lux table must be a multiple of 3 and within the range [6, %d]\n",
                        __func__, max_ints);
                goto done;
        }
        if ((value[n - 2] | value[n - 1] | value[n]) != 0) {
                dev_err(dev, "%s: The last 3 entries in the lux table must be zeros.\n",
                        __func__);
                goto done;
        }

        memcpy(chip->als_settings.als_device_lux, &value[1],
               value[0] * sizeof(value[1]));

        ret = len;

done:
        mutex_unlock(&chip->als_mutex);

        return ret;
}

static IIO_CONST_ATTR(in_illuminance_calibscale_available, "1 8 16 111");
static IIO_CONST_ATTR(in_illuminance_integration_time_available,
                      "0.050 0.100 0.150 0.200 0.250 0.300 0.350 0.400 0.450 0.500 0.550 0.600 0.650");
static IIO_DEVICE_ATTR_RW(in_illuminance_input_target, 0);
static IIO_DEVICE_ATTR_WO(in_illuminance_calibrate, 0);
static IIO_DEVICE_ATTR_RW(in_illuminance_lux_table, 0);

static struct attribute *sysfs_attrs_ctrl[] = {
        &iio_const_attr_in_illuminance_calibscale_available.dev_attr.attr,
        &iio_const_attr_in_illuminance_integration_time_available.dev_attr.attr,
        &iio_dev_attr_in_illuminance_input_target.dev_attr.attr,
        &iio_dev_attr_in_illuminance_calibrate.dev_attr.attr,
        &iio_dev_attr_in_illuminance_lux_table.dev_attr.attr,
        NULL
};

static const struct attribute_group tsl2583_attribute_group = {
        .attrs = sysfs_attrs_ctrl,
};

static const struct iio_chan_spec tsl2583_channels[] = {
        {
                .type = IIO_LIGHT,
                .modified = 1,
                .channel2 = IIO_MOD_LIGHT_IR,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        },
        {
                .type = IIO_LIGHT,
                .modified = 1,
                .channel2 = IIO_MOD_LIGHT_BOTH,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        },
        {
                .type = IIO_LIGHT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
                                      BIT(IIO_CHAN_INFO_CALIBBIAS) |
                                      BIT(IIO_CHAN_INFO_CALIBSCALE) |
                                      BIT(IIO_CHAN_INFO_INT_TIME),
        },
};

static int tsl2583_set_pm_runtime_busy(struct tsl2583_chip *chip, bool on)
{
        int ret;

        if (on) {
                ret = pm_runtime_get_sync(&chip->client->dev);
                if (ret < 0)
                        pm_runtime_put_noidle(&chip->client->dev);
        } else {
                pm_runtime_mark_last_busy(&chip->client->dev);
                ret = pm_runtime_put_autosuspend(&chip->client->dev);
        }

        return ret;
}

static int tsl2583_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int ret, pm_ret;

        ret = tsl2583_set_pm_runtime_busy(chip, true);
        if (ret < 0)
                return ret;

        mutex_lock(&chip->als_mutex);

        ret = -EINVAL;
        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (chan->type == IIO_LIGHT) {
                        ret = tsl2583_get_lux(indio_dev);
                        if (ret < 0)
                                goto read_done;

                        /*
                         * From page 20 of the TSL2581, TSL2583 data
                         * sheet (TAOS134 − MARCH 2011):
                         *
                         * One of the photodiodes (channel 0) is
                         * sensitive to both visible and infrared light,
                         * while the second photodiode (channel 1) is
                         * sensitive primarily to infrared light.
                         */
                        if (chan->channel2 == IIO_MOD_LIGHT_BOTH)
                                *val = chip->als_cur_info.als_ch0;
                        else
                                *val = chip->als_cur_info.als_ch1;

                        ret = IIO_VAL_INT;
                }
                break;
        case IIO_CHAN_INFO_PROCESSED:
                if (chan->type == IIO_LIGHT) {
                        ret = tsl2583_get_lux(indio_dev);
                        if (ret < 0)
                                goto read_done;

                        *val = ret;
                        ret = IIO_VAL_INT;
                }
                break;
        case IIO_CHAN_INFO_CALIBBIAS:
                if (chan->type == IIO_LIGHT) {
                        *val = chip->als_settings.als_gain_trim;
                        ret = IIO_VAL_INT;
                }
                break;
        case IIO_CHAN_INFO_CALIBSCALE:
                if (chan->type == IIO_LIGHT) {
                        *val = gainadj[chip->als_settings.als_gain].mean;
                        ret = IIO_VAL_INT;
                }
                break;
        case IIO_CHAN_INFO_INT_TIME:
                if (chan->type == IIO_LIGHT) {
                        *val = 0;
                        *val2 = chip->als_settings.als_time;
                        ret = IIO_VAL_INT_PLUS_MICRO;
                }
                break;
        default:
                break;
        }

read_done:
        mutex_unlock(&chip->als_mutex);

        if (ret < 0)
                return ret;

        /*
         * Preserve the ret variable if the call to
         * tsl2583_set_pm_runtime_busy() is successful so the reading
         * (if applicable) is returned to user space.
         */
        pm_ret = tsl2583_set_pm_runtime_busy(chip, false);
        if (pm_ret < 0)
                return pm_ret;

        return ret;
}

static int tsl2583_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int ret;

        ret = tsl2583_set_pm_runtime_busy(chip, true);
        if (ret < 0)
                return ret;

        mutex_lock(&chip->als_mutex);

        ret = -EINVAL;
        switch (mask) {
        case IIO_CHAN_INFO_CALIBBIAS:
                if (chan->type == IIO_LIGHT) {
                        chip->als_settings.als_gain_trim = val;
                        ret = 0;
                }
                break;
        case IIO_CHAN_INFO_CALIBSCALE:
                if (chan->type == IIO_LIGHT) {
                        unsigned int i;

                        for (i = 0; i < ARRAY_SIZE(gainadj); i++) {
                                if (gainadj[i].mean == val) {
                                        chip->als_settings.als_gain = i;
                                        ret = tsl2583_set_als_gain(chip);
                                        break;
                                }
                        }
                }
                break;
        case IIO_CHAN_INFO_INT_TIME:
                if (chan->type == IIO_LIGHT && !val && val2 >= 50 &&
                    val2 <= 650 && !(val2 % 50)) {
                        chip->als_settings.als_time = val2;
                        ret = tsl2583_set_als_time(chip);
                }
                break;
        default:
                break;
        }

        mutex_unlock(&chip->als_mutex);

        if (ret < 0)
                return ret;

        ret = tsl2583_set_pm_runtime_busy(chip, false);
        if (ret < 0)
                return ret;

        return ret;
}

static const struct iio_info tsl2583_info = {
        .attrs = &tsl2583_attribute_group,
        .read_raw = tsl2583_read_raw,
        .write_raw = tsl2583_write_raw,
};

static int tsl2583_probe(struct i2c_client *clientp,
                         const struct i2c_device_id *idp)
{
        int ret;
        struct tsl2583_chip *chip;
        struct iio_dev *indio_dev;

        if (!i2c_check_functionality(clientp->adapter,
                                     I2C_FUNC_SMBUS_BYTE_DATA)) {
                dev_err(&clientp->dev, "%s: i2c smbus byte data functionality is unsupported\n",
                        __func__);
                return -EOPNOTSUPP;
        }

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

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

        mutex_init(&chip->als_mutex);

        ret = i2c_smbus_read_byte_data(clientp,
                                       TSL2583_CMD_REG | TSL2583_CHIPID);
        if (ret < 0) {
                dev_err(&clientp->dev,
                        "%s: failed to read the chip ID register\n", __func__);
                return ret;
        }

        if ((ret & TSL2583_CHIP_ID_MASK) != TSL2583_CHIP_ID) {
                dev_err(&clientp->dev, "%s: received an unknown chip ID %x\n",
                        __func__, ret);
                return -EINVAL;
        }

        indio_dev->info = &tsl2583_info;
        indio_dev->channels = tsl2583_channels;
        indio_dev->num_channels = ARRAY_SIZE(tsl2583_channels);
        indio_dev->dev.parent = &clientp->dev;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->name = chip->client->name;

        pm_runtime_enable(&clientp->dev);
        pm_runtime_set_autosuspend_delay(&clientp->dev,
                                         TSL2583_POWER_OFF_DELAY_MS);
        pm_runtime_use_autosuspend(&clientp->dev);

        ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
        if (ret) {
                dev_err(&clientp->dev, "%s: iio registration failed\n",
                        __func__);
                return ret;
        }

        /* Load up the V2 defaults (these are hard coded defaults for now) */
        tsl2583_defaults(chip);

        dev_info(&clientp->dev, "Light sensor found.\n");

        return 0;
}

static int tsl2583_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        struct tsl2583_chip *chip = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

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

        return tsl2583_set_power_state(chip, TSL2583_CNTL_PWR_OFF);
}

static int __maybe_unused tsl2583_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int ret;

        mutex_lock(&chip->als_mutex);

        ret = tsl2583_set_power_state(chip, TSL2583_CNTL_PWR_OFF);

        mutex_unlock(&chip->als_mutex);

        return ret;
}

static int __maybe_unused tsl2583_resume(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int ret;

        mutex_lock(&chip->als_mutex);

        ret = tsl2583_chip_init_and_power_on(indio_dev);

        mutex_unlock(&chip->als_mutex);

        return ret;
}

static const struct dev_pm_ops tsl2583_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
                                pm_runtime_force_resume)
        SET_RUNTIME_PM_OPS(tsl2583_suspend, tsl2583_resume, NULL)
};

static const struct i2c_device_id tsl2583_idtable[] = {
        { "tsl2580", 0 },
        { "tsl2581", 1 },
        { "tsl2583", 2 },
        {}
};
MODULE_DEVICE_TABLE(i2c, tsl2583_idtable);

static const struct of_device_id tsl2583_of_match[] = {
        { .compatible = "amstaos,tsl2580", },
        { .compatible = "amstaos,tsl2581", },
        { .compatible = "amstaos,tsl2583", },
        { },
};
MODULE_DEVICE_TABLE(of, tsl2583_of_match);

/* Driver definition */
static struct i2c_driver tsl2583_driver = {
        .driver = {
                .name = "tsl2583",
                .pm = &tsl2583_pm_ops,
                .of_match_table = tsl2583_of_match,
        },
        .id_table = tsl2583_idtable,
        .probe = tsl2583_probe,
        .remove = tsl2583_remove,
};
module_i2c_driver(tsl2583_driver);

MODULE_AUTHOR("J. August Brenner <jbrenner@taosinc.com>");
MODULE_AUTHOR("Brian Masney <masneyb@onstation.org>");
MODULE_DESCRIPTION("TAOS tsl2583 ambient light sensor driver");
MODULE_LICENSE("GPL");