// SPDX-License-Identifier: GPL-2.0
/*
 * mlx90635.c - Melexis MLX90635 contactless IR temperature sensor
 *
 * Copyright (c) 2023 Melexis <cmo@melexis.com>
 *
 * Driver for the Melexis MLX90635 I2C 16-bit IR thermopile sensor
 */
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/iopoll.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/limits.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/math64.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>

/* Memory sections addresses */
#define MLX90635_ADDR_RAM       0x0000 /* Start address of ram */
#define MLX90635_ADDR_EEPROM    0x0018 /* Start address of user eeprom */

/* EEPROM addresses - used at startup */
#define MLX90635_EE_I2C_CFG     0x0018 /* I2C address register initial value */
#define MLX90635_EE_CTRL1       0x001A /* Control register1 initial value */
#define MLX90635_EE_CTRL2       0x001C /* Control register2 initial value */

#define MLX90635_EE_Ha          0x001E /* Ha customer calib value reg 16bit */
#define MLX90635_EE_Hb          0x0020 /* Hb customer calib value reg 16bit */
#define MLX90635_EE_Fa          0x0026 /* Fa calibration register 32bit */
#define MLX90635_EE_FASCALE     0x002A /* Scaling coefficient for Fa register 16bit */
#define MLX90635_EE_Ga          0x002C /* Ga calibration register 16bit */
#define MLX90635_EE_Fb          0x002E /* Fb calibration register 16bit */
#define MLX90635_EE_Ea          0x0030 /* Ea calibration register 32bit */
#define MLX90635_EE_Eb          0x0034 /* Eb calibration register 32bit */
#define MLX90635_EE_P_G         0x0038 /* P_G calibration register 16bit */
#define MLX90635_EE_P_O         0x003A /* P_O calibration register 16bit */
#define MLX90635_EE_Aa          0x003C /* Aa calibration register 16bit */
#define MLX90635_EE_VERSION     0x003E /* Version bits 4:7 and 12:15 */
#define MLX90635_EE_Gb          0x0040 /* Gb calibration register 16bit */

/* Device status register - volatile */
#define MLX90635_REG_STATUS     0x0000
#define   MLX90635_STAT_BUSY BIT(6) /* Device busy indicator */
#define   MLX90635_STAT_BRST BIT(5) /* Brown out reset indicator */
#define   MLX90635_STAT_CYCLE_POS GENMASK(4, 2) /* Data position */
#define   MLX90635_STAT_END_CONV BIT(1) /* End of conversion indicator */
#define   MLX90635_STAT_DATA_RDY BIT(0) /* Data ready indicator */

/* EEPROM control register address - volatile */
#define MLX90635_REG_EE         0x000C
#define   MLX90635_EE_ACTIVE BIT(4) /* Power-on EEPROM */
#define   MLX90635_EE_BUSY_MASK BIT(15)

#define MLX90635_REG_CMD        0x0010 /* Command register address */

/* Control register1 address - volatile */
#define MLX90635_REG_CTRL1      0x0014
#define   MLX90635_CTRL1_REFRESH_RATE_MASK GENMASK(2, 0)
#define   MLX90635_CTRL1_RES_CTRL_MASK GENMASK(4, 3)
#define   MLX90635_CTRL1_TABLE_MASK BIT(15) /* Table select */

/* Control register2 address - volatile */
#define   MLX90635_REG_CTRL2    0x0016
#define   MLX90635_CTRL2_BURST_CNT_MASK GENMASK(10, 6) /* Burst count */
#define   MLX90635_CTRL2_MODE_MASK GENMASK(12, 11) /* Power mode */
#define   MLX90635_CTRL2_SOB_MASK BIT(15)

/* PowerModes statuses */
#define MLX90635_PWR_STATUS_HALT 0
#define MLX90635_PWR_STATUS_SLEEP_STEP 1
#define MLX90635_PWR_STATUS_STEP 2
#define MLX90635_PWR_STATUS_CONTINUOUS 3

/* Measurement data addresses */
#define MLX90635_RESULT_1   0x0002
#define MLX90635_RESULT_2   0x0004
#define MLX90635_RESULT_3   0x0006
#define MLX90635_RESULT_4   0x0008
#define MLX90635_RESULT_5   0x000A

/* Timings (ms) */
#define MLX90635_TIMING_RST_MIN 200 /* Minimum time after addressed reset command */
#define MLX90635_TIMING_RST_MAX 250 /* Maximum time after addressed reset command */
#define MLX90635_TIMING_POLLING 10000 /* Time between bit polling*/
#define MLX90635_TIMING_EE_ACTIVE_MIN 100 /* Minimum time after activating the EEPROM for read */
#define MLX90635_TIMING_EE_ACTIVE_MAX 150 /* Maximum time after activating the EEPROM for read */

/* Magic constants */
#define MLX90635_ID_DSPv1 0x01 /* EEPROM DSP version */
#define MLX90635_RESET_CMD  0x0006 /* Reset sensor (address or global) */
#define MLX90635_MAX_MEAS_NUM   31 /* Maximum number of measurements in list */
#define MLX90635_PTAT_DIV 12   /* Used to divide the PTAT value in pre-processing */
#define MLX90635_IR_DIV 24   /* Used to divide the IR value in pre-processing */
#define MLX90635_SLEEP_DELAY_MS 6000 /* Autosleep delay */
#define MLX90635_MEAS_MAX_TIME 2000 /* Max measurement time in ms for the lowest refresh rate */
#define MLX90635_READ_RETRIES 100 /* Number of read retries before quitting with timeout error */
#define MLX90635_VERSION_MASK (GENMASK(15, 12) | GENMASK(7, 4))
#define MLX90635_DSP_VERSION(reg) (((reg & GENMASK(14, 12)) >> 9) | ((reg & GENMASK(6, 4)) >> 4))
#define MLX90635_DSP_FIXED BIT(15)


/**
 * struct mlx90635_data - private data for the MLX90635 device
 * @client: I2C client of the device
 * @lock: Internal mutex because multiple reads are needed for single triggered
 *        measurement to ensure data consistency
 * @regmap: Regmap of the device registers
 * @regmap_ee: Regmap of the device EEPROM which can be cached
 * @emissivity: Object emissivity from 0 to 1000 where 1000 = 1
 * @regulator: Regulator of the device
 * @powerstatus: Current POWER status of the device
 * @interaction_ts: Timestamp of the last temperature read that is used
 *                  for power management in jiffies
 */
struct mlx90635_data {
        struct i2c_client *client;
        struct mutex lock;
        struct regmap *regmap;
        struct regmap *regmap_ee;
        u16 emissivity;
        struct regulator *regulator;
        int powerstatus;
        unsigned long interaction_ts;
};

static const struct regmap_range mlx90635_volatile_reg_range[] = {
        regmap_reg_range(MLX90635_REG_STATUS, MLX90635_REG_STATUS),
        regmap_reg_range(MLX90635_RESULT_1, MLX90635_RESULT_5),
        regmap_reg_range(MLX90635_REG_EE, MLX90635_REG_EE),
        regmap_reg_range(MLX90635_REG_CMD, MLX90635_REG_CMD),
        regmap_reg_range(MLX90635_REG_CTRL1, MLX90635_REG_CTRL2),
};

static const struct regmap_access_table mlx90635_volatile_regs_tbl = {
        .yes_ranges = mlx90635_volatile_reg_range,
        .n_yes_ranges = ARRAY_SIZE(mlx90635_volatile_reg_range),
};

static const struct regmap_range mlx90635_read_reg_range[] = {
        regmap_reg_range(MLX90635_REG_STATUS, MLX90635_REG_STATUS),
        regmap_reg_range(MLX90635_RESULT_1, MLX90635_RESULT_5),
        regmap_reg_range(MLX90635_REG_EE, MLX90635_REG_EE),
        regmap_reg_range(MLX90635_REG_CMD, MLX90635_REG_CMD),
        regmap_reg_range(MLX90635_REG_CTRL1, MLX90635_REG_CTRL2),
};

static const struct regmap_access_table mlx90635_readable_regs_tbl = {
        .yes_ranges = mlx90635_read_reg_range,
        .n_yes_ranges = ARRAY_SIZE(mlx90635_read_reg_range),
};

static const struct regmap_range mlx90635_no_write_reg_range[] = {
        regmap_reg_range(MLX90635_RESULT_1, MLX90635_RESULT_5),
};

static const struct regmap_access_table mlx90635_writeable_regs_tbl = {
        .no_ranges = mlx90635_no_write_reg_range,
        .n_no_ranges = ARRAY_SIZE(mlx90635_no_write_reg_range),
};

static const struct regmap_config mlx90635_regmap = {
        .name = "mlx90635-registers",
        .reg_stride = 1,
        .reg_bits = 16,
        .val_bits = 16,

        .volatile_table = &mlx90635_volatile_regs_tbl,
        .rd_table = &mlx90635_readable_regs_tbl,
        .wr_table = &mlx90635_writeable_regs_tbl,

        .use_single_read = true,
        .use_single_write = true,
        .can_multi_write = false,
        .reg_format_endian = REGMAP_ENDIAN_BIG,
        .val_format_endian = REGMAP_ENDIAN_BIG,
        .cache_type = REGCACHE_RBTREE,
};

static const struct regmap_range mlx90635_read_ee_range[] = {
        regmap_reg_range(MLX90635_EE_I2C_CFG, MLX90635_EE_CTRL2),
        regmap_reg_range(MLX90635_EE_Ha, MLX90635_EE_Gb),
};

static const struct regmap_access_table mlx90635_readable_ees_tbl = {
        .yes_ranges = mlx90635_read_ee_range,
        .n_yes_ranges = ARRAY_SIZE(mlx90635_read_ee_range),
};

static const struct regmap_range mlx90635_no_write_ee_range[] = {
        regmap_reg_range(MLX90635_ADDR_EEPROM, MLX90635_EE_Gb),
};

static const struct regmap_access_table mlx90635_writeable_ees_tbl = {
        .no_ranges = mlx90635_no_write_ee_range,
        .n_no_ranges = ARRAY_SIZE(mlx90635_no_write_ee_range),
};

static const struct regmap_config mlx90635_regmap_ee = {
        .name = "mlx90635-eeprom",
        .reg_stride = 1,
        .reg_bits = 16,
        .val_bits = 16,

        .volatile_table = NULL,
        .rd_table = &mlx90635_readable_ees_tbl,
        .wr_table = &mlx90635_writeable_ees_tbl,

        .use_single_read = true,
        .use_single_write = true,
        .can_multi_write = false,
        .reg_format_endian = REGMAP_ENDIAN_BIG,
        .val_format_endian = REGMAP_ENDIAN_BIG,
        .cache_type = REGCACHE_RBTREE,
};

/**
 * mlx90635_reset_delay() - Give the mlx90635 some time to reset properly
 * If this is not done, the following I2C command(s) will not be accepted.
 */
static void mlx90635_reset_delay(void)
{
        usleep_range(MLX90635_TIMING_RST_MIN, MLX90635_TIMING_RST_MAX);
}

static int mlx90635_pwr_sleep_step(struct mlx90635_data *data)
{
        int ret;

        if (data->powerstatus == MLX90635_PWR_STATUS_SLEEP_STEP)
                return 0;

        ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL2, MLX90635_CTRL2_MODE_MASK,
                                FIELD_PREP(MLX90635_CTRL2_MODE_MASK, MLX90635_PWR_STATUS_SLEEP_STEP));
        if (ret < 0)
                return ret;

        data->powerstatus = MLX90635_PWR_STATUS_SLEEP_STEP;
        return 0;
}

static int mlx90635_pwr_continuous(struct mlx90635_data *data)
{
        int ret;

        if (data->powerstatus == MLX90635_PWR_STATUS_CONTINUOUS)
                return 0;

        ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL2, MLX90635_CTRL2_MODE_MASK,
                                FIELD_PREP(MLX90635_CTRL2_MODE_MASK, MLX90635_PWR_STATUS_CONTINUOUS));
        if (ret < 0)
                return ret;

        data->powerstatus = MLX90635_PWR_STATUS_CONTINUOUS;
        return 0;
}

static int mlx90635_read_ee_register(struct regmap *regmap, u16 reg_lsb,
                                     s32 *reg_value)
{
        unsigned int read;
        u32 value;
        int ret;

        ret = regmap_read(regmap, reg_lsb + 2, &read);
        if (ret < 0)
                return ret;

        value = read;

        ret = regmap_read(regmap, reg_lsb, &read);
        if (ret < 0)
                return ret;

        *reg_value = (read << 16) | (value & 0xffff);

        return 0;
}

static int mlx90635_read_ee_ambient(struct regmap *regmap, s16 *PG, s16 *PO, s16 *Gb)
{
        unsigned int read_tmp;
        int ret;

        ret = regmap_read(regmap, MLX90635_EE_P_O, &read_tmp);
        if (ret < 0)
                return ret;
        *PO = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_P_G, &read_tmp);
        if (ret < 0)
                return ret;
        *PG = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_Gb, &read_tmp);
        if (ret < 0)
                return ret;
        *Gb = (u16)read_tmp;

        return 0;
}

static int mlx90635_read_ee_object(struct regmap *regmap, u32 *Ea, u32 *Eb, u32 *Fa, s16 *Fb,
                                   s16 *Ga, s16 *Gb, s16 *Ha, s16 *Hb, u16 *Fa_scale)
{
        unsigned int read_tmp;
        int ret;

        ret = mlx90635_read_ee_register(regmap, MLX90635_EE_Ea, Ea);
        if (ret < 0)
                return ret;

        ret = mlx90635_read_ee_register(regmap, MLX90635_EE_Eb, Eb);
        if (ret < 0)
                return ret;

        ret = mlx90635_read_ee_register(regmap, MLX90635_EE_Fa, Fa);
        if (ret < 0)
                return ret;

        ret = regmap_read(regmap, MLX90635_EE_Ha, &read_tmp);
        if (ret < 0)
                return ret;
        *Ha = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_Hb, &read_tmp);
        if (ret < 0)
                return ret;
        *Hb = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_Ga, &read_tmp);
        if (ret < 0)
                return ret;
        *Ga = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_Gb, &read_tmp);
        if (ret < 0)
                return ret;
        *Gb = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_Fb, &read_tmp);
        if (ret < 0)
                return ret;
        *Fb = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_EE_FASCALE, &read_tmp);
        if (ret < 0)
                return ret;
        *Fa_scale = (u16)read_tmp;

        return 0;
}

static int mlx90635_calculate_dataset_ready_time(struct mlx90635_data *data, int *refresh_time)
{
        unsigned int reg;
        int ret;

        ret = regmap_read(data->regmap, MLX90635_REG_CTRL1, &reg);
        if (ret < 0)
                return ret;

        *refresh_time = 2 * (MLX90635_MEAS_MAX_TIME >> FIELD_GET(MLX90635_CTRL1_REFRESH_RATE_MASK, reg)) + 80;

        return 0;
}

static int mlx90635_perform_measurement_burst(struct mlx90635_data *data)
{
        unsigned int reg_status;
        int refresh_time;
        int ret;

        ret = regmap_write_bits(data->regmap, MLX90635_REG_STATUS,
                                MLX90635_STAT_END_CONV, MLX90635_STAT_END_CONV);
        if (ret < 0)
                return ret;

        ret = mlx90635_calculate_dataset_ready_time(data, &refresh_time);
        if (ret < 0)
                return ret;

        ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL2,
                                FIELD_PREP(MLX90635_CTRL2_SOB_MASK, 1),
                                FIELD_PREP(MLX90635_CTRL2_SOB_MASK, 1));
        if (ret < 0)
                return ret;

        msleep(refresh_time); /* Wait minimum time for dataset to be ready */

        ret = regmap_read_poll_timeout(data->regmap, MLX90635_REG_STATUS, reg_status,
                                       (!(reg_status & MLX90635_STAT_END_CONV)) == 0,
                                       MLX90635_TIMING_POLLING, MLX90635_READ_RETRIES * 10000);
        if (ret < 0) {
                dev_err(&data->client->dev, "data not ready");
                return -ETIMEDOUT;
        }

        return 0;
}

static int mlx90635_read_ambient_raw(struct regmap *regmap,
                                     s16 *ambient_new_raw, s16 *ambient_old_raw)
{
        unsigned int read_tmp;
        int ret;

        ret = regmap_read(regmap, MLX90635_RESULT_2, &read_tmp);
        if (ret < 0)
                return ret;
        *ambient_new_raw = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_RESULT_3, &read_tmp);
        if (ret < 0)
                return ret;
        *ambient_old_raw = (s16)read_tmp;

        return 0;
}

static int mlx90635_read_object_raw(struct regmap *regmap, s16 *object_raw)
{
        unsigned int read_tmp;
        s16 read;
        int ret;

        ret = regmap_read(regmap, MLX90635_RESULT_1, &read_tmp);
        if (ret < 0)
                return ret;

        read = (s16)read_tmp;

        ret = regmap_read(regmap, MLX90635_RESULT_4, &read_tmp);
        if (ret < 0)
                return ret;
        *object_raw = (read - (s16)read_tmp) / 2;

        return 0;
}

static int mlx90635_read_all_channel(struct mlx90635_data *data,
                                     s16 *ambient_new_raw, s16 *ambient_old_raw,
                                     s16 *object_raw)
{
        int ret;

        mutex_lock(&data->lock);
        if (data->powerstatus == MLX90635_PWR_STATUS_SLEEP_STEP) {
                /* Trigger measurement in Sleep Step mode */
                ret = mlx90635_perform_measurement_burst(data);
                if (ret < 0)
                        goto read_unlock;
        }

        ret = mlx90635_read_ambient_raw(data->regmap, ambient_new_raw,
                                        ambient_old_raw);
        if (ret < 0)
                goto read_unlock;

        ret = mlx90635_read_object_raw(data->regmap, object_raw);
read_unlock:
        mutex_unlock(&data->lock);
        return ret;
}

static s64 mlx90635_preprocess_temp_amb(s16 ambient_new_raw,
                                        s16 ambient_old_raw, s16 Gb)
{
        s64 VR_Ta, kGb, tmp;

        kGb = ((s64)Gb * 1000LL) >> 10ULL;
        VR_Ta = (s64)ambient_old_raw * 1000000LL +
                kGb * div64_s64(((s64)ambient_new_raw * 1000LL),
                        (MLX90635_PTAT_DIV));
        tmp = div64_s64(
                         div64_s64(((s64)ambient_new_raw * 1000000000000LL),
                                   (MLX90635_PTAT_DIV)), VR_Ta);
        return div64_s64(tmp << 19ULL, 1000LL);
}

static s64 mlx90635_preprocess_temp_obj(s16 object_raw,
                                        s16 ambient_new_raw,
                                        s16 ambient_old_raw, s16 Gb)
{
        s64 VR_IR, kGb, tmp;

        kGb = ((s64)Gb * 1000LL) >> 10ULL;
        VR_IR = (s64)ambient_old_raw * 1000000LL +
                kGb * (div64_s64((s64)ambient_new_raw * 1000LL,
                        MLX90635_PTAT_DIV));
        tmp = div64_s64(
                        div64_s64((s64)(object_raw * 1000000LL),
                                   MLX90635_IR_DIV) * 1000000LL,
                        VR_IR);
        return div64_s64((tmp << 19ULL), 1000LL);
}

static s32 mlx90635_calc_temp_ambient(s16 ambient_new_raw, s16 ambient_old_raw,
                                      u16 P_G, u16 P_O, s16 Gb)
{
        s64 kPG, kPO, AMB;

        AMB = mlx90635_preprocess_temp_amb(ambient_new_raw, ambient_old_raw,
                                           Gb);
        kPG = ((s64)P_G * 1000000LL) >> 9ULL;
        kPO = AMB - (((s64)P_O * 1000LL) >> 1ULL);

        return 30 * 1000LL + div64_s64(kPO * 1000000LL, kPG);
}

static s32 mlx90635_calc_temp_object_iteration(s32 prev_object_temp, s64 object,
                                               s64 TAdut, s64 TAdut4, s16 Ga,
                                               u32 Fa, u16 Fa_scale, s16 Fb,
                                               s16 Ha, s16 Hb, u16 emissivity)
{
        s64 calcedGa, calcedGb, calcedFa, Alpha_corr;
        s64 Ha_customer, Hb_customer;

        Ha_customer = ((s64)Ha * 1000000LL) >> 14ULL;
        Hb_customer = ((s64)Hb * 100) >> 10ULL;

        calcedGa = ((s64)((s64)Ga * (prev_object_temp - 35 * 1000LL)
                             * 1000LL)) >> 24LL;
        calcedGb = ((s64)(Fb * (TAdut - 30 * 1000000LL))) >> 24LL;

        Alpha_corr = ((s64)((s64)Fa * Ha_customer * 10000LL) >> Fa_scale);
        Alpha_corr *= ((s64)(1 * 1000000LL + calcedGa + calcedGb));

        Alpha_corr = div64_s64(Alpha_corr, 1000LL);
        Alpha_corr *= emissivity;
        Alpha_corr = div64_s64(Alpha_corr, 100LL);
        calcedFa = div64_s64((s64)object * 100000000000LL, Alpha_corr);

        return (int_sqrt64(int_sqrt64(calcedFa * 100000000LL + TAdut4))
                - 27315 - Hb_customer) * 10;
}

static s64 mlx90635_calc_ta4(s64 TAdut, s64 scale)
{
        return (div64_s64(TAdut, scale) + 27315) *
                (div64_s64(TAdut, scale) + 27315) *
                (div64_s64(TAdut, scale) + 27315) *
                (div64_s64(TAdut, scale) + 27315);
}

static s32 mlx90635_calc_temp_object(s64 object, s64 ambient, u32 Ea, u32 Eb,
                                     s16 Ga, u32 Fa, u16 Fa_scale, s16 Fb, s16 Ha, s16 Hb,
                                     u16 tmp_emi)
{
        s64 kTA, kTA0, TAdut, TAdut4;
        s64 temp = 35000;
        s8 i;

        kTA = (Ea * 1000LL) >> 16LL;
        kTA0 = (Eb * 1000LL) >> 8LL;
        TAdut = div64_s64(((ambient - kTA0) * 1000000LL), kTA) + 30 * 1000000LL;
        TAdut4 = mlx90635_calc_ta4(TAdut, 10000LL);

        /* Iterations of calculation as described in datasheet */
        for (i = 0; i < 5; ++i) {
                temp = mlx90635_calc_temp_object_iteration(temp, object, TAdut, TAdut4,
                                                           Ga, Fa, Fa_scale, Fb, Ha, Hb,
                                                           tmp_emi);
        }
        return temp;
}

static int mlx90635_calc_object(struct mlx90635_data *data, int *val)
{
        s16 ambient_new_raw, ambient_old_raw, object_raw;
        s16 Fb, Ga, Gb, Ha, Hb;
        s64 object, ambient;
        u32 Ea, Eb, Fa;
        u16 Fa_scale;
        int ret;

        ret = mlx90635_read_ee_object(data->regmap_ee, &Ea, &Eb, &Fa, &Fb, &Ga, &Gb, &Ha, &Hb, &Fa_scale);
        if (ret < 0)
                return ret;

        ret = mlx90635_read_all_channel(data,
                                        &ambient_new_raw, &ambient_old_raw,
                                        &object_raw);
        if (ret < 0)
                return ret;

        ambient = mlx90635_preprocess_temp_amb(ambient_new_raw,
                                               ambient_old_raw, Gb);
        object = mlx90635_preprocess_temp_obj(object_raw,
                                              ambient_new_raw,
                                              ambient_old_raw, Gb);

        *val = mlx90635_calc_temp_object(object, ambient, Ea, Eb, Ga, Fa, Fa_scale, Fb,
                                         Ha, Hb, data->emissivity);
        return 0;
}

static int mlx90635_calc_ambient(struct mlx90635_data *data, int *val)
{
        s16 ambient_new_raw, ambient_old_raw;
        s16 PG, PO, Gb;
        int ret;

        ret = mlx90635_read_ee_ambient(data->regmap_ee, &PG, &PO, &Gb);
        if (ret < 0)
                return ret;

        mutex_lock(&data->lock);
        if (data->powerstatus == MLX90635_PWR_STATUS_SLEEP_STEP) {
                ret = mlx90635_perform_measurement_burst(data);
                if (ret < 0)
                        goto read_ambient_unlock;
        }

        ret = mlx90635_read_ambient_raw(data->regmap, &ambient_new_raw,
                                        &ambient_old_raw);
read_ambient_unlock:
        mutex_unlock(&data->lock);
        if (ret < 0)
                return ret;

        *val = mlx90635_calc_temp_ambient(ambient_new_raw, ambient_old_raw,
                                          PG, PO, Gb);
        return ret;
}

static int mlx90635_get_refresh_rate(struct mlx90635_data *data,
                                     unsigned int *refresh_rate)
{
        unsigned int reg;
        int ret;

        ret = regmap_read(data->regmap, MLX90635_REG_CTRL1, &reg);
        if (ret < 0)
                return ret;

        *refresh_rate = FIELD_GET(MLX90635_CTRL1_REFRESH_RATE_MASK, reg);

        return 0;
}

static const struct {
        int val;
        int val2;
} mlx90635_freqs[] = {
        { 0, 200000 },
        { 0, 500000 },
        { 0, 900000 },
        { 1, 700000 },
        { 3, 0 },
        { 4, 800000 },
        { 6, 900000 },
        { 8, 900000 }
};

/**
 * mlx90635_pm_interaction_wakeup() - Measure time between user interactions to change powermode
 * @data: pointer to mlx90635_data object containing interaction_ts information
 *
 * Switch to continuous mode when interaction is faster than MLX90635_MEAS_MAX_TIME. Update the
 * interaction_ts for each function call with the jiffies to enable measurement between function
 * calls. Initial value of the interaction_ts needs to be set before this function call.
 */
static int mlx90635_pm_interaction_wakeup(struct mlx90635_data *data)
{
        unsigned long now;
        int ret;

        now = jiffies;
        if (time_in_range(now, data->interaction_ts,
                          data->interaction_ts +
                          msecs_to_jiffies(MLX90635_MEAS_MAX_TIME + 100))) {
                ret = mlx90635_pwr_continuous(data);
                if (ret < 0)
                        return ret;
        }

        data->interaction_ts = now;

        return 0;
}

static int mlx90635_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *channel, int *val,
                             int *val2, long mask)
{
        struct mlx90635_data *data = iio_priv(indio_dev);
        int ret;
        int cr;

        pm_runtime_get_sync(&data->client->dev);
        ret = mlx90635_pm_interaction_wakeup(data);
        if (ret < 0)
                goto mlx90635_read_raw_pm;

        switch (mask) {
        case IIO_CHAN_INFO_PROCESSED:
                switch (channel->channel2) {
                case IIO_MOD_TEMP_AMBIENT:
                        ret = mlx90635_calc_ambient(data, val);
                        if (ret < 0)
                                goto mlx90635_read_raw_pm;

                        ret = IIO_VAL_INT;
                        break;
                case IIO_MOD_TEMP_OBJECT:
                        ret = mlx90635_calc_object(data, val);
                        if (ret < 0)
                                goto mlx90635_read_raw_pm;

                        ret = IIO_VAL_INT;
                        break;
                default:
                        ret = -EINVAL;
                        break;
                }
                break;
        case IIO_CHAN_INFO_CALIBEMISSIVITY:
                if (data->emissivity == 1000) {
                        *val = 1;
                        *val2 = 0;
                } else {
                        *val = 0;
                        *val2 = data->emissivity * 1000;
                }
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        case IIO_CHAN_INFO_SAMP_FREQ:
                ret = mlx90635_get_refresh_rate(data, &cr);
                if (ret < 0)
                        goto mlx90635_read_raw_pm;

                *val = mlx90635_freqs[cr].val;
                *val2 = mlx90635_freqs[cr].val2;
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        default:
                ret = -EINVAL;
                break;
        }

mlx90635_read_raw_pm:
        pm_runtime_put_autosuspend(&data->client->dev);
        return ret;
}

static int mlx90635_write_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *channel, int val,
                              int val2, long mask)
{
        struct mlx90635_data *data = iio_priv(indio_dev);
        int ret;
        int i;

        switch (mask) {
        case IIO_CHAN_INFO_CALIBEMISSIVITY:
                /* Confirm we are within 0 and 1.0 */
                if (val < 0 || val2 < 0 || val > 1 ||
                    (val == 1 && val2 != 0))
                        return -EINVAL;
                data->emissivity = val * 1000 + val2 / 1000;
                return 0;
        case IIO_CHAN_INFO_SAMP_FREQ:
                for (i = 0; i < ARRAY_SIZE(mlx90635_freqs); i++) {
                        if (val == mlx90635_freqs[i].val &&
                            val2 == mlx90635_freqs[i].val2)
                                break;
                }
                if (i == ARRAY_SIZE(mlx90635_freqs))
                        return -EINVAL;

                ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL1,
                                        MLX90635_CTRL1_REFRESH_RATE_MASK, i);

                return ret;
        default:
                return -EINVAL;
        }
}

static int mlx90635_read_avail(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_SAMP_FREQ:
                *vals = (int *)mlx90635_freqs;
                *type = IIO_VAL_INT_PLUS_MICRO;
                *length = 2 * ARRAY_SIZE(mlx90635_freqs);
                return IIO_AVAIL_LIST;
        default:
                return -EINVAL;
        }
}

static const struct iio_chan_spec mlx90635_channels[] = {
        {
                .type = IIO_TEMP,
                .modified = 1,
                .channel2 = IIO_MOD_TEMP_AMBIENT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
        },
        {
                .type = IIO_TEMP,
                .modified = 1,
                .channel2 = IIO_MOD_TEMP_OBJECT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
                        BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
        },
};

static const struct iio_info mlx90635_info = {
        .read_raw = mlx90635_read_raw,
        .write_raw = mlx90635_write_raw,
        .read_avail = mlx90635_read_avail,
};

static void mlx90635_sleep(void *_data)
{
        struct mlx90635_data *data = _data;

        mlx90635_pwr_sleep_step(data);
}

static int mlx90635_suspend(struct mlx90635_data *data)
{
        return mlx90635_pwr_sleep_step(data);
}

static int mlx90635_wakeup(struct mlx90635_data *data)
{
        s16 Fb, Ga, Gb, Ha, Hb, PG, PO;
        unsigned int dsp_version;
        u32 Ea, Eb, Fa;
        u16 Fa_scale;
        int ret;

        regcache_cache_bypass(data->regmap_ee, false);
        regcache_cache_only(data->regmap_ee, false);
        regcache_cache_only(data->regmap, false);

        ret = mlx90635_pwr_continuous(data);
        if (ret < 0) {
                dev_err(&data->client->dev, "Switch to continuous mode failed\n");
                return ret;
        }
        ret = regmap_write_bits(data->regmap, MLX90635_REG_EE,
                                MLX90635_EE_ACTIVE, MLX90635_EE_ACTIVE);
        if (ret < 0) {
                dev_err(&data->client->dev, "Powering EEPROM failed\n");
                return ret;
        }
        usleep_range(MLX90635_TIMING_EE_ACTIVE_MIN, MLX90635_TIMING_EE_ACTIVE_MAX);

        regcache_mark_dirty(data->regmap_ee);

        ret = regcache_sync(data->regmap_ee);
        if (ret < 0) {
                dev_err(&data->client->dev,
                        "Failed to sync cache: %d\n", ret);
                return ret;
        }

        ret = mlx90635_read_ee_ambient(data->regmap_ee, &PG, &PO, &Gb);
        if (ret < 0) {
                dev_err(&data->client->dev,
                        "Failed to read to cache Ambient coefficients EEPROM region: %d\n", ret);
                return ret;
        }

        ret = mlx90635_read_ee_object(data->regmap_ee, &Ea, &Eb, &Fa, &Fb, &Ga, &Gb, &Ha, &Hb, &Fa_scale);
        if (ret < 0) {
                dev_err(&data->client->dev,
                        "Failed to read to cache Object coefficients EEPROM region: %d\n", ret);
                return ret;
        }

        ret = regmap_read(data->regmap_ee, MLX90635_EE_VERSION, &dsp_version);
        if (ret < 0) {
                dev_err(&data->client->dev,
                        "Failed to read to cache of EEPROM version: %d\n", ret);
                return ret;
        }

        regcache_cache_only(data->regmap_ee, true);

        return ret;
}

static void mlx90635_disable_regulator(void *_data)
{
        struct mlx90635_data *data = _data;
        int ret;

        ret = regulator_disable(data->regulator);
        if (ret < 0)
                dev_err(regmap_get_device(data->regmap),
                        "Failed to disable power regulator: %d\n", ret);
}

static int mlx90635_enable_regulator(struct mlx90635_data *data)
{
        int ret;

        ret = regulator_enable(data->regulator);
        if (ret < 0) {
                dev_err(regmap_get_device(data->regmap), "Failed to enable power regulator!\n");
                return ret;
        }

        mlx90635_reset_delay();

        return ret;
}

static int mlx90635_probe(struct i2c_client *client)
{
        struct mlx90635_data *mlx90635;
        struct iio_dev *indio_dev;
        unsigned int dsp_version;
        struct regmap *regmap;
        struct regmap *regmap_ee;
        int ret;

        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*mlx90635));
        if (!indio_dev)
                return -ENOMEM;

        regmap = devm_regmap_init_i2c(client, &mlx90635_regmap);
        if (IS_ERR(regmap))
                return dev_err_probe(&client->dev, PTR_ERR(regmap),
                                     "failed to allocate regmap\n");

        regmap_ee = devm_regmap_init_i2c(client, &mlx90635_regmap_ee);
        if (IS_ERR(regmap_ee))
                return dev_err_probe(&client->dev, PTR_ERR(regmap_ee),
                                     "failed to allocate EEPROM regmap\n");

        mlx90635 = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        mlx90635->client = client;
        mlx90635->regmap = regmap;
        mlx90635->regmap_ee = regmap_ee;
        mlx90635->powerstatus = MLX90635_PWR_STATUS_SLEEP_STEP;

        mutex_init(&mlx90635->lock);
        indio_dev->name = "mlx90635";
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &mlx90635_info;
        indio_dev->channels = mlx90635_channels;
        indio_dev->num_channels = ARRAY_SIZE(mlx90635_channels);

        mlx90635->regulator = devm_regulator_get(&client->dev, "vdd");
        if (IS_ERR(mlx90635->regulator))
                return dev_err_probe(&client->dev, PTR_ERR(mlx90635->regulator),
                                     "failed to get vdd regulator");

        ret = mlx90635_enable_regulator(mlx90635);
        if (ret < 0)
                return ret;

        ret = devm_add_action_or_reset(&client->dev, mlx90635_disable_regulator,
                                       mlx90635);
        if (ret < 0)
                return ret;

        ret = mlx90635_wakeup(mlx90635);
        if (ret < 0)
                return dev_err_probe(&client->dev, ret, "wakeup failed\n");

        ret = devm_add_action_or_reset(&client->dev, mlx90635_sleep, mlx90635);
        if (ret < 0)
                return ret;

        ret = regmap_read(mlx90635->regmap_ee, MLX90635_EE_VERSION, &dsp_version);
        if (ret < 0)
                return dev_err_probe(&client->dev, ret, "read of version failed\n");

        dsp_version = dsp_version & MLX90635_VERSION_MASK;

        if (FIELD_GET(MLX90635_DSP_FIXED, dsp_version)) {
                if (MLX90635_DSP_VERSION(dsp_version) == MLX90635_ID_DSPv1) {
                        dev_dbg(&client->dev,
                                "Detected DSP v1 calibration %x\n", dsp_version);
                } else {
                        dev_dbg(&client->dev,
                                "Detected Unknown EEPROM calibration %lx\n",
                                MLX90635_DSP_VERSION(dsp_version));
                }
        } else {
                return dev_err_probe(&client->dev, -EPROTONOSUPPORT,
                        "Wrong fixed top bit %x (expected 0x8X0X)\n",
                        dsp_version);
        }

        mlx90635->emissivity = 1000;
        mlx90635->interaction_ts = jiffies; /* Set initial value */

        pm_runtime_get_noresume(&client->dev);
        pm_runtime_set_active(&client->dev);

        ret = devm_pm_runtime_enable(&client->dev);
        if (ret)
                return dev_err_probe(&client->dev, ret,
                                     "failed to enable powermanagement\n");

        pm_runtime_set_autosuspend_delay(&client->dev, MLX90635_SLEEP_DELAY_MS);
        pm_runtime_use_autosuspend(&client->dev);
        pm_runtime_put_autosuspend(&client->dev);

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

static const struct i2c_device_id mlx90635_id[] = {
        { "mlx90635" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mlx90635_id);

static const struct of_device_id mlx90635_of_match[] = {
        { .compatible = "melexis,mlx90635" },
        { }
};
MODULE_DEVICE_TABLE(of, mlx90635_of_match);

static int mlx90635_pm_suspend(struct device *dev)
{
        struct mlx90635_data *data = iio_priv(dev_get_drvdata(dev));
        int ret;

        ret = mlx90635_suspend(data);
        if (ret < 0)
                return ret;

        ret = regulator_disable(data->regulator);
        if (ret < 0)
                dev_err(regmap_get_device(data->regmap),
                        "Failed to disable power regulator: %d\n", ret);

        return ret;
}

static int mlx90635_pm_resume(struct device *dev)
{
        struct mlx90635_data *data = iio_priv(dev_get_drvdata(dev));
        int ret;

        ret = mlx90635_enable_regulator(data);
        if (ret < 0)
                return ret;

        return mlx90635_wakeup(data);
}

static int mlx90635_pm_runtime_suspend(struct device *dev)
{
        struct mlx90635_data *data = iio_priv(dev_get_drvdata(dev));

        return mlx90635_pwr_sleep_step(data);
}

static const struct dev_pm_ops mlx90635_pm_ops = {
        SYSTEM_SLEEP_PM_OPS(mlx90635_pm_suspend, mlx90635_pm_resume)
        RUNTIME_PM_OPS(mlx90635_pm_runtime_suspend, NULL, NULL)
};

static struct i2c_driver mlx90635_driver = {
        .driver = {
                .name   = "mlx90635",
                .of_match_table = mlx90635_of_match,
                .pm     = pm_ptr(&mlx90635_pm_ops),
        },
        .probe = mlx90635_probe,
        .id_table = mlx90635_id,
};
module_i2c_driver(mlx90635_driver);

MODULE_AUTHOR("Crt Mori <cmo@melexis.com>");
MODULE_DESCRIPTION("Melexis MLX90635 contactless Infra Red temperature sensor driver");
MODULE_LICENSE("GPL");