/*
 * Device driver for monitoring ambient light intensity (lux)
 * within the TAOS tsl258x family of devices (tsl2580, tsl2581).
 *
 * Copyright (c) 2011, TAOS Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#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>

#define TSL258X_MAX_DEVICE_REGS         32

/* Triton register offsets */
#define TSL258X_REG_MAX         8

/* Device Registers and Masks */
#define TSL258X_CNTRL                   0x00
#define TSL258X_ALS_TIME                0X01
#define TSL258X_INTERRUPT               0x02
#define TSL258X_GAIN                    0x07
#define TSL258X_REVID                   0x11
#define TSL258X_CHIPID                  0x12
#define TSL258X_ALS_CHAN0LO             0x14
#define TSL258X_ALS_CHAN0HI             0x15
#define TSL258X_ALS_CHAN1LO             0x16
#define TSL258X_ALS_CHAN1HI             0x17
#define TSL258X_TMR_LO                  0x18
#define TSL258X_TMR_HI                  0x19

/* tsl2583 cmd reg masks */
#define TSL258X_CMD_REG                 0x80
#define TSL258X_CMD_SPL_FN              0x60
#define TSL258X_CMD_ALS_INT_CLR 0X01

/* tsl2583 cntrl reg masks */
#define TSL258X_CNTL_ADC_ENBL   0x02
#define TSL258X_CNTL_PWR_ON             0x01

/* tsl2583 status reg masks */
#define TSL258X_STA_ADC_VALID   0x01
#define TSL258X_STA_ADC_INTR    0x10

/* Lux calculation constants */
#define TSL258X_LUX_CALC_OVER_FLOW              65535

enum {
        TSL258X_CHIP_UNKNOWN = 0,
        TSL258X_CHIP_WORKING = 1,
        TSL258X_CHIP_SUSPENDED = 2
};

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

struct taos_settings {
        int als_time;
        int als_gain;
        int als_gain_trim;
        int als_cal_target;
};

struct tsl2583_chip {
        struct mutex als_mutex;
        struct i2c_client *client;
        struct taos_als_info als_cur_info;
        struct taos_settings taos_settings;
        int als_time_scale;
        int als_saturation;
        int taos_chip_status;
        u8 taos_config[8];
};

/*
 * Initial values for device - this values can/will be changed by driver.
 * and applications as needed.
 * These values are dynamic.
 */
static const u8 taos_config[8] = {
                0x00, 0xee, 0x00, 0x03, 0x00, 0xFF, 0xFF, 0x00
}; /*   cntrl atime intC  Athl0 Athl1 Athh0 Athh1 gain */

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

/* This structure is intentionally large to accommodate updates via sysfs. */
/* Sized to 11 = max 10 segments + 1 termination segment */
/* Assumption is one and only one type of glass used  */
static struct taos_lux taos_device_lux[11] = {
        {  9830,  8520, 15729 },
        { 12452, 10807, 23344 },
        { 14746,  6383, 11705 },
        { 17695,  4063,  6554 },
};

struct gainadj {
        s16 ch0;
        s16 ch1;
};

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

/*
 * Provides initial operational parameter defaults.
 * These defaults may be changed through the device's sysfs files.
 */
static void taos_defaults(struct tsl2583_chip *chip)
{
        /* Operational parameters */
        chip->taos_settings.als_time = 100;
        /* must be a multiple of 50mS */
        chip->taos_settings.als_gain = 0;
        /* this is actually an index into the gain table */
        /* assume clear glass as default */
        chip->taos_settings.als_gain_trim = 1000;
        /* default gain trim to account for aperture effects */
        chip->taos_settings.als_cal_target = 130;
        /* Known external ALS reading used for calibration */
}

/*
 * Read a number of bytes starting at register (reg) location.
 * Return 0, or i2c_smbus_write_byte ERROR code.
 */
static int
taos_i2c_read(struct i2c_client *client, u8 reg, u8 *val, unsigned int len)
{
        int i, ret;

        for (i = 0; i < len; i++) {
                /* select register to write */
                ret = i2c_smbus_write_byte(client, (TSL258X_CMD_REG | reg));
                if (ret < 0) {
                        dev_err(&client->dev,
                                "taos_i2c_read failed to write register %x\n",
                                reg);
                        return ret;
                }
                /* read the data */
                *val = i2c_smbus_read_byte(client);
                val++;
                reg++;
        }
        return 0;
}

/*
 * 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 taos_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 taos_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 taos_lux *p;
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        int i, ret;
        u32 ch0lux = 0;
        u32 ch1lux = 0;

        if (mutex_trylock(&chip->als_mutex) == 0) {
                dev_info(&chip->client->dev, "taos_get_lux device is busy\n");
                return chip->als_cur_info.lux; /* busy, so return LAST VALUE */
        }

        if (chip->taos_chip_status != TSL258X_CHIP_WORKING) {
                /* device is not enabled */
                dev_err(&chip->client->dev, "taos_get_lux device is not enabled\n");
                ret = -EBUSY;
                goto out_unlock;
        }

        ret = taos_i2c_read(chip->client, (TSL258X_CMD_REG), &buf[0], 1);
        if (ret < 0) {
                dev_err(&chip->client->dev, "taos_get_lux failed to read CMD_REG\n");
                goto out_unlock;
        }
        /* is data new & valid */
        if (!(buf[0] & TSL258X_STA_ADC_INTR)) {
                dev_err(&chip->client->dev, "taos_get_lux data not valid\n");
                ret = chip->als_cur_info.lux; /* return LAST VALUE */
                goto out_unlock;
        }

        for (i = 0; i < 4; i++) {
                int reg = TSL258X_CMD_REG | (TSL258X_ALS_CHAN0LO + i);

                ret = taos_i2c_read(chip->client, reg, &buf[i], 1);
                if (ret < 0) {
                        dev_err(&chip->client->dev,
                                "taos_get_lux failed to read register %x\n",
                                reg);
                        goto out_unlock;
                }
        }

        /*
         * clear status, really interrupt status (interrupts are off), but
         * we use the bit anyway - don't forget 0x80 - this is a command
         */
        ret = i2c_smbus_write_byte(chip->client,
                                   (TSL258X_CMD_REG | TSL258X_CMD_SPL_FN |
                                    TSL258X_CMD_ALS_INT_CLR));

        if (ret < 0) {
                dev_err(&chip->client->dev,
                        "taos_i2c_write_command failed in taos_get_lux, err = %d\n",
                        ret);
                goto out_unlock; /* 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) {
                /* have no data, so return LAST VALUE */
                ret = 0;
                chip->als_cur_info.lux = 0;
                goto out_unlock;
        }
        /* calculate ratio */
        ratio = (ch1 << 15) / ch0;
        /* convert to unscaled lux using the pointer to the table */
        for (p = (struct taos_lux *)taos_device_lux;
             p->ratio != 0 && p->ratio < ratio; p++)
                ;

        if (p->ratio == 0) {
                lux = 0;
        } else {
                ch0lux = ((ch0 * p->ch0) +
                          (gainadj[chip->taos_settings.als_gain].ch0 >> 1))
                         / gainadj[chip->taos_settings.als_gain].ch0;
                ch1lux = ((ch1 * p->ch1) +
                          (gainadj[chip->taos_settings.als_gain].ch1 >> 1))
                         / gainadj[chip->taos_settings.als_gain].ch1;
                lux = ch0lux - ch1lux;
        }

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

        /* 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 taos_device_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->taos_settings.als_gain_trim;
        lux64 >>= 13;
        lux = lux64;
        lux = (lux + 500) / 1000;
        if (lux > TSL258X_LUX_CALC_OVER_FLOW) { /* check for overflow */
return_max:
                lux = TSL258X_LUX_CALC_OVER_FLOW;
        }

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

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

/*
 * Obtain single reading and calculate the als_gain_trim (later used
 * to derive actual lux).
 * Return updated gain_trim value.
 */
static int taos_als_calibrate(struct iio_dev *indio_dev)
{
        struct tsl2583_chip *chip = iio_priv(indio_dev);
        u8 reg_val;
        unsigned int gain_trim_val;
        int ret;
        int lux_val;

        ret = i2c_smbus_write_byte(chip->client,
                                   (TSL258X_CMD_REG | TSL258X_CNTRL));
        if (ret < 0) {
                dev_err(&chip->client->dev,
                        "taos_als_calibrate failed to reach the CNTRL register, ret=%d\n",
                        ret);
                return ret;
        }

        reg_val = i2c_smbus_read_byte(chip->client);
        if ((reg_val & (TSL258X_CNTL_ADC_ENBL | TSL258X_CNTL_PWR_ON))
                        != (TSL258X_CNTL_ADC_ENBL | TSL258X_CNTL_PWR_ON)) {
                dev_err(&chip->client->dev,
                        "taos_als_calibrate failed: device not powered on with ADC enabled\n");
                return -1;
        }

        ret = i2c_smbus_write_byte(chip->client,
                                   (TSL258X_CMD_REG | TSL258X_CNTRL));
        if (ret < 0) {
                dev_err(&chip->client->dev,
                        "taos_als_calibrate failed to reach the STATUS register, ret=%d\n",
                        ret);
                return ret;
        }
        reg_val = i2c_smbus_read_byte(chip->client);

        if ((reg_val & TSL258X_STA_ADC_VALID) != TSL258X_STA_ADC_VALID) {
                dev_err(&chip->client->dev,
                        "taos_als_calibrate failed: STATUS - ADC not valid.\n");
                return -ENODATA;
        }
        lux_val = taos_get_lux(indio_dev);
        if (lux_val < 0) {
                dev_err(&chip->client->dev, "taos_als_calibrate failed to get lux\n");
                return lux_val;
        }
        gain_trim_val = (unsigned int)(((chip->taos_settings.als_cal_target)
                        * chip->taos_settings.als_gain_trim) / lux_val);

        if ((gain_trim_val < 250) || (gain_trim_val > 4000)) {
                dev_err(&chip->client->dev,
                        "taos_als_calibrate failed: trim_val of %d is out of range\n",
                        gain_trim_val);
                return -ENODATA;
        }
        chip->taos_settings.als_gain_trim = (int)gain_trim_val;

        return (int)gain_trim_val;
}

/*
 * Turn the device on.
 * Configuration must be set before calling this function.
 */
static int taos_chip_on(struct iio_dev *indio_dev)
{
        int i;
        int ret;
        u8 *uP;
        u8 utmp;
        int als_count;
        int als_time;
        struct tsl2583_chip *chip = iio_priv(indio_dev);

        /* and make sure we're not already on */
        if (chip->taos_chip_status == TSL258X_CHIP_WORKING) {
                /* if forcing a register update - turn off, then on */
                dev_info(&chip->client->dev, "device is already enabled\n");
                return -EINVAL;
        }

        /* determine als integration register */
        als_count = (chip->taos_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;
        chip->taos_config[TSL258X_ALS_TIME] = 256 - als_count;

        /* Set the gain based on taos_settings struct */
        chip->taos_config[TSL258X_GAIN] = chip->taos_settings.als_gain;

        /* 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;

        /*
         * TSL258x Specific power-on / adc enable sequence
         * Power on the device 1st.
         */
        utmp = TSL258X_CNTL_PWR_ON;
        ret = i2c_smbus_write_byte_data(chip->client,
                                        TSL258X_CMD_REG | TSL258X_CNTRL, utmp);
        if (ret < 0) {
                dev_err(&chip->client->dev, "taos_chip_on failed on CNTRL reg.\n");
                return ret;
        }

        /*
         * Use the following shadow copy for our delay before enabling ADC.
         * Write all the registers.
         */
        for (i = 0, uP = chip->taos_config; i < TSL258X_REG_MAX; i++) {
                ret = i2c_smbus_write_byte_data(chip->client,
                                                TSL258X_CMD_REG + i,
                                                *uP++);
                if (ret < 0) {
                        dev_err(&chip->client->dev,
                                "taos_chip_on failed on reg %d.\n", i);
                        return ret;
                }
        }

        usleep_range(3000, 3500);
        /*
         * NOW enable the ADC
         * initialize the desired mode of operation
         */
        utmp = TSL258X_CNTL_PWR_ON | TSL258X_CNTL_ADC_ENBL;
        ret = i2c_smbus_write_byte_data(chip->client,
                                        TSL258X_CMD_REG | TSL258X_CNTRL,
                                        utmp);
        if (ret < 0) {
                dev_err(&chip->client->dev, "taos_chip_on failed on 2nd CTRL reg.\n");
                return ret;
        }
        chip->taos_chip_status = TSL258X_CHIP_WORKING;

        return ret;
}

static int taos_chip_off(struct iio_dev *indio_dev)
{
        struct tsl2583_chip *chip = iio_priv(indio_dev);

        /* turn device off */
        chip->taos_chip_status = TSL258X_CHIP_SUSPENDED;
        return i2c_smbus_write_byte_data(chip->client,
                                        TSL258X_CMD_REG | TSL258X_CNTRL,
                                        0x00);
}

/* Sysfs Interface Functions */

static ssize_t taos_power_state_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);

        return sprintf(buf, "%d\n", chip->taos_chip_status);
}

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

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

        if (!value)
                taos_chip_off(indio_dev);
        else
                taos_chip_on(indio_dev);

        return len;
}

static ssize_t taos_gain_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);
        char gain[4] = {0};

        switch (chip->taos_settings.als_gain) {
        case 0:
                strcpy(gain, "001");
                break;
        case 1:
                strcpy(gain, "008");
                break;
        case 2:
                strcpy(gain, "016");
                break;
        case 3:
                strcpy(gain, "111");
                break;
        }

        return sprintf(buf, "%s\n", gain);
}

static ssize_t taos_gain_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))
                return -EINVAL;

        switch (value) {
        case 1:
                chip->taos_settings.als_gain = 0;
                break;
        case 8:
                chip->taos_settings.als_gain = 1;
                break;
        case 16:
                chip->taos_settings.als_gain = 2;
                break;
        case 111:
                chip->taos_settings.als_gain = 3;
                break;
        default:
                dev_err(dev, "Invalid Gain Index (must be 1,8,16,111)\n");
                return -1;
        }

        return len;
}

static ssize_t taos_gain_available_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        return sprintf(buf, "%s\n", "1 8 16 111");
}

static ssize_t taos_als_time_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);

        return sprintf(buf, "%d\n", chip->taos_settings.als_time);
}

static ssize_t taos_als_time_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))
                return -EINVAL;

        if ((value < 50) || (value > 650))
                return -EINVAL;

        if (value % 50)
                return -EINVAL;

        chip->taos_settings.als_time = value;

        return len;
}

static ssize_t taos_als_time_available_show(struct device *dev,
                                            struct device_attribute *attr,
                                            char *buf)
{
        return sprintf(buf, "%s\n",
                "50 100 150 200 250 300 350 400 450 500 550 600 650");
}

static ssize_t taos_als_trim_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);

        return sprintf(buf, "%d\n", chip->taos_settings.als_gain_trim);
}

static ssize_t taos_als_trim_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))
                return -EINVAL;

        if (value)
                chip->taos_settings.als_gain_trim = value;

        return len;
}

static ssize_t taos_als_cal_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);

        return sprintf(buf, "%d\n", chip->taos_settings.als_cal_target);
}

static ssize_t taos_als_cal_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))
                return -EINVAL;

        if (value)
                chip->taos_settings.als_cal_target = value;

        return len;
}

static ssize_t taos_lux_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        int ret;

        ret = taos_get_lux(dev_to_iio_dev(dev));
        if (ret < 0)
                return ret;

        return sprintf(buf, "%d\n", ret);
}

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

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

        if (value == 1)
                taos_als_calibrate(indio_dev);

        return len;
}

static ssize_t taos_luxtable_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        int i;
        int offset = 0;

        for (i = 0; i < ARRAY_SIZE(taos_device_lux); i++) {
                offset += sprintf(buf + offset, "%u,%u,%u,",
                                  taos_device_lux[i].ratio,
                                  taos_device_lux[i].ch0,
                                  taos_device_lux[i].ch1);
                if (taos_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 taos_luxtable_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[ARRAY_SIZE(taos_device_lux) * 3 + 1];
        int n;

        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 > ((ARRAY_SIZE(taos_device_lux) - 1) * 3)) {
                dev_info(dev, "LUX TABLE INPUT ERROR 1 Value[0]=%d\n", n);
                return -EINVAL;
        }
        if ((value[(n - 2)] | value[(n - 1)] | value[n]) != 0) {
                dev_info(dev, "LUX TABLE INPUT ERROR 2 Value[0]=%d\n", n);
                return -EINVAL;
        }

        if (chip->taos_chip_status == TSL258X_CHIP_WORKING)
                taos_chip_off(indio_dev);

        /* Zero out the table */
        memset(taos_device_lux, 0, sizeof(taos_device_lux));
        memcpy(taos_device_lux, &value[1], (value[0] * 4));

        taos_chip_on(indio_dev);

        return len;
}

static DEVICE_ATTR(power_state, S_IRUGO | S_IWUSR,
                taos_power_state_show, taos_power_state_store);

static DEVICE_ATTR(illuminance0_calibscale, S_IRUGO | S_IWUSR,
                taos_gain_show, taos_gain_store);
static DEVICE_ATTR(illuminance0_calibscale_available, S_IRUGO,
                taos_gain_available_show, NULL);

static DEVICE_ATTR(illuminance0_integration_time, S_IRUGO | S_IWUSR,
                taos_als_time_show, taos_als_time_store);
static DEVICE_ATTR(illuminance0_integration_time_available, S_IRUGO,
                taos_als_time_available_show, NULL);

static DEVICE_ATTR(illuminance0_calibbias, S_IRUGO | S_IWUSR,
                taos_als_trim_show, taos_als_trim_store);

static DEVICE_ATTR(illuminance0_input_target, S_IRUGO | S_IWUSR,
                taos_als_cal_target_show, taos_als_cal_target_store);

static DEVICE_ATTR(illuminance0_input, S_IRUGO, taos_lux_show, NULL);
static DEVICE_ATTR(illuminance0_calibrate, S_IWUSR, NULL, taos_do_calibrate);
static DEVICE_ATTR(illuminance0_lux_table, S_IRUGO | S_IWUSR,
                taos_luxtable_show, taos_luxtable_store);

static struct attribute *sysfs_attrs_ctrl[] = {
        &dev_attr_power_state.attr,
        &dev_attr_illuminance0_calibscale.attr,                 /* Gain  */
        &dev_attr_illuminance0_calibscale_available.attr,
        &dev_attr_illuminance0_integration_time.attr,   /* I time*/
        &dev_attr_illuminance0_integration_time_available.attr,
        &dev_attr_illuminance0_calibbias.attr,                  /* trim  */
        &dev_attr_illuminance0_input_target.attr,
        &dev_attr_illuminance0_input.attr,
        &dev_attr_illuminance0_calibrate.attr,
        &dev_attr_illuminance0_lux_table.attr,
        NULL
};

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

/* Use the default register values to identify the Taos device */
static int taos_tsl258x_device(unsigned char *bufp)
{
        return ((bufp[TSL258X_CHIPID] & 0xf0) == 0x90);
}

static const struct iio_info tsl2583_info = {
        .attrs = &tsl2583_attribute_group,
        .driver_module = THIS_MODULE,
};

/*
 * Client probe function - When a valid device is found, the driver's device
 * data structure is updated, and initialization completes successfully.
 */
static int taos_probe(struct i2c_client *clientp,
                      const struct i2c_device_id *idp)
{
        int i, ret;
        unsigned char buf[TSL258X_MAX_DEVICE_REGS];
        struct tsl2583_chip *chip;
        struct iio_dev *indio_dev;

        if (!i2c_check_functionality(clientp->adapter,
                                     I2C_FUNC_SMBUS_BYTE_DATA)) {
                dev_err(&clientp->dev, "taos_probe() - i2c smbus byte data func unsupported\n");
                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);
        chip->taos_chip_status = TSL258X_CHIP_UNKNOWN;
        memcpy(chip->taos_config, taos_config, sizeof(chip->taos_config));

        for (i = 0; i < TSL258X_MAX_DEVICE_REGS; i++) {
                ret = i2c_smbus_write_byte(clientp,
                                (TSL258X_CMD_REG | (TSL258X_CNTRL + i)));
                if (ret < 0) {
                        dev_err(&clientp->dev,
                                "i2c_smbus_write_byte to cmd reg failed in taos_probe(), err = %d\n",
                                ret);
                        return ret;
                }
                ret = i2c_smbus_read_byte(clientp);
                if (ret < 0) {
                        dev_err(&clientp->dev,
                                "i2c_smbus_read_byte from reg failed in taos_probe(), err = %d\n",
                                ret);
                        return ret;
                }
                buf[i] = ret;
        }

        if (!taos_tsl258x_device(buf)) {
                dev_info(&clientp->dev,
                         "i2c device found but does not match expected id in taos_probe()\n");
                return -EINVAL;
        }

        ret = i2c_smbus_write_byte(clientp, (TSL258X_CMD_REG | TSL258X_CNTRL));
        if (ret < 0) {
                dev_err(&clientp->dev,
                        "i2c_smbus_write_byte() to cmd reg failed in taos_probe(), err = %d\n",
                        ret);
                return ret;
        }

        indio_dev->info = &tsl2583_info;
        indio_dev->dev.parent = &clientp->dev;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->name = chip->client->name;
        ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
        if (ret) {
                dev_err(&clientp->dev, "iio registration failed\n");
                return ret;
        }

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

        /* Make sure the chip is on */
        taos_chip_on(indio_dev);

        dev_info(&clientp->dev, "Light sensor found.\n");
        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int taos_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 = 0;

        mutex_lock(&chip->als_mutex);

        if (chip->taos_chip_status == TSL258X_CHIP_WORKING) {
                ret = taos_chip_off(indio_dev);
                chip->taos_chip_status = TSL258X_CHIP_SUSPENDED;
        }

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

static int taos_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 = 0;

        mutex_lock(&chip->als_mutex);

        if (chip->taos_chip_status == TSL258X_CHIP_SUSPENDED)
                ret = taos_chip_on(indio_dev);

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

static SIMPLE_DEV_PM_OPS(taos_pm_ops, taos_suspend, taos_resume);
#define TAOS_PM_OPS (&taos_pm_ops)
#else
#define TAOS_PM_OPS NULL
#endif

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

/* Driver definition */
static struct i2c_driver taos_driver = {
        .driver = {
                .name = "tsl2583",
                .pm = TAOS_PM_OPS,
        },
        .id_table = taos_idtable,
        .probe = taos_probe,
};
module_i2c_driver(taos_driver);

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