// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Texas Instruments INA238 power monitor chip
 * Datasheet: https://www.ti.com/product/ina238
 *
 * Copyright (C) 2021 Nathan Rossi <nathan.rossi@digi.com>
 */

#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regmap.h>

/* INA238 register definitions */
#define INA238_CONFIG                   0x0
#define INA238_ADC_CONFIG               0x1
#define INA238_SHUNT_CALIBRATION        0x2
#define SQ52206_SHUNT_TEMPCO            0x3
#define INA238_SHUNT_VOLTAGE            0x4
#define INA238_BUS_VOLTAGE              0x5
#define INA238_DIE_TEMP                 0x6
#define INA238_CURRENT                  0x7
#define INA238_POWER                    0x8
#define SQ52206_ENERGY                  0x9
#define SQ52206_CHARGE                  0xa
#define INA238_DIAG_ALERT               0xb
#define INA238_SHUNT_OVER_VOLTAGE       0xc
#define INA238_SHUNT_UNDER_VOLTAGE      0xd
#define INA238_BUS_OVER_VOLTAGE         0xe
#define INA238_BUS_UNDER_VOLTAGE        0xf
#define INA238_TEMP_LIMIT               0x10
#define INA238_POWER_LIMIT              0x11
#define SQ52206_POWER_PEAK              0x20
#define INA238_DEVICE_ID                0x3f /* not available on INA237 */

#define INA238_CONFIG_ADCRANGE          BIT(4)
#define SQ52206_CONFIG_ADCRANGE_HIGH    BIT(4)
#define SQ52206_CONFIG_ADCRANGE_LOW     BIT(3)

#define INA238_DIAG_ALERT_TMPOL         BIT(7)
#define INA238_DIAG_ALERT_SHNTOL        BIT(6)
#define INA238_DIAG_ALERT_SHNTUL        BIT(5)
#define INA238_DIAG_ALERT_BUSOL         BIT(4)
#define INA238_DIAG_ALERT_BUSUL         BIT(3)
#define INA238_DIAG_ALERT_POL           BIT(2)

#define INA238_REGISTERS                0x20

#define INA238_RSHUNT_DEFAULT           2500    /* uOhm */

/* Default configuration of device on reset. */
#define INA238_CONFIG_DEFAULT           0
#define SQ52206_CONFIG_DEFAULT          0x0005
/* 16 sample averaging, 1052us conversion time, continuous mode */
#define INA238_ADC_CONFIG_DEFAULT       0xfb6a
/* Configure alerts to be based on averaged value (SLOWALERT) */
#define INA238_DIAG_ALERT_DEFAULT       0x2000
#define INA238_DIAG_ALERT_APOL          BIT(12)
/*
 * This driver uses a fixed calibration value in order to scale current/power
 * based on a fixed shunt resistor value. This allows for conversion within the
 * device to avoid integer limits whilst current/power accuracy is scaled
 * relative to the shunt resistor value within the driver. This is similar to
 * how the ina2xx driver handles current/power scaling.
 *
 * To achieve the best possible dynamic range, the value of the shunt voltage
 * register should match the value of the current register. With that, the shunt
 * voltage of 0x7fff = 32,767 uV = 163,785 uV matches the maximum current,
 * and no accuracy is lost. Experiments with a real chip show that this is
 * achieved by setting the SHUNT_CAL register to a value of 0x1000 = 4,096.
 * Per datasheet,
 *  SHUNT_CAL = 819.2 x 10^6 x CURRENT_LSB x Rshunt
 *            = 819,200,000 x CURRENT_LSB x Rshunt
 * With SHUNT_CAL set to 4,096, we get
 *  CURRENT_LSB = 4,096 / (819,200,000 x Rshunt)
 * Assuming an Rshunt value of 5 mOhm, we get
 *  CURRENT_LSB = 4,096 / (819,200,000 x 0.005) = 1mA
 * and thus a dynamic range of 1mA ... 32,767mA, which is sufficient for most
 * applications. The actual dynamic range is of course determined by the actual
 * shunt resistor value.
 *
 * Power and energy values are scaled accordingly.
 */
#define INA238_CALIBRATION_VALUE        4096
#define INA238_FIXED_SHUNT              5000

#define INA238_SHUNT_VOLTAGE_LSB        5000    /* 5 uV/lsb, in nV */
#define INA238_BUS_VOLTAGE_LSB          3125000 /* 3.125 mV/lsb, in nV */
#define SQ52206_BUS_VOLTAGE_LSB         3750000 /* 3.75 mV/lsb, in nV */

#define NUNIT_PER_MUNIT         1000000 /* n[AV] -> m[AV] */

static const struct regmap_config ina238_regmap_config = {
        .max_register = INA238_REGISTERS,
        .reg_bits = 8,
        .val_bits = 16,
};

enum ina238_ids { ina228, ina237, ina238, ina700, ina780, sq52206 };

struct ina238_config {
        bool has_20bit_voltage_current; /* vshunt, vbus and current are 20-bit fields */
        bool has_power_highest;         /* chip detection power peak */
        bool has_energy;                /* chip detection energy */
        u8 temp_resolution;             /* temperature register resolution in bit */
        u16 config_default;             /* Power-on default state */
        u32 power_calculate_factor;     /* fixed parameter for power calculation, from datasheet */
        u32 bus_voltage_lsb;            /* bus voltage LSB, in nV */
        int current_lsb;                /* current LSB, in uA */
};

struct ina238_data {
        const struct ina238_config *config;
        struct i2c_client *client;
        struct regmap *regmap;
        u32 rshunt;
        int gain;
        u32 voltage_lsb[2];             /* shunt, bus voltage LSB, in nV */
        int current_lsb;                /* current LSB, in uA */
        int power_lsb;                  /* power LSB, in uW */
        int energy_lsb;                 /* energy LSB, in uJ */
};

static const struct ina238_config ina238_config[] = {
        [ina228] = {
                .has_20bit_voltage_current = true,
                .has_energy = true,
                .has_power_highest = false,
                .power_calculate_factor = 20,
                .config_default = INA238_CONFIG_DEFAULT,
                .bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
                .temp_resolution = 16,
        },
        [ina237] = {
                .has_20bit_voltage_current = false,
                .has_energy = false,
                .has_power_highest = false,
                .power_calculate_factor = 20,
                .config_default = INA238_CONFIG_DEFAULT,
                .bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
                .temp_resolution = 12,
        },
        [ina238] = {
                .has_20bit_voltage_current = false,
                .has_energy = false,
                .has_power_highest = false,
                .power_calculate_factor = 20,
                .config_default = INA238_CONFIG_DEFAULT,
                .bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
                .temp_resolution = 12,
        },
        [ina700] = {
                .has_20bit_voltage_current = false,
                .has_energy = true,
                .has_power_highest = false,
                .power_calculate_factor = 20,
                .config_default = INA238_CONFIG_DEFAULT,
                .bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
                .temp_resolution = 12,
                .current_lsb = 480,
        },
        [ina780] = {
                .has_20bit_voltage_current = false,
                .has_energy = true,
                .has_power_highest = false,
                .power_calculate_factor = 20,
                .config_default = INA238_CONFIG_DEFAULT,
                .bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
                .temp_resolution = 12,
                .current_lsb = 2400,
        },
        [sq52206] = {
                .has_20bit_voltage_current = false,
                .has_energy = true,
                .has_power_highest = true,
                .power_calculate_factor = 24,
                .config_default = SQ52206_CONFIG_DEFAULT,
                .bus_voltage_lsb = SQ52206_BUS_VOLTAGE_LSB,
                .temp_resolution = 16,
        },
};

static int ina238_read_reg24(const struct i2c_client *client, u8 reg, u32 *val)
{
        u8 data[3];
        int err;

        /* 24-bit register read */
        err = i2c_smbus_read_i2c_block_data(client, reg, 3, data);
        if (err < 0)
                return err;
        if (err != 3)
                return -EIO;
        *val = (data[0] << 16) | (data[1] << 8) | data[2];

        return 0;
}

static int ina238_read_reg40(const struct i2c_client *client, u8 reg, u64 *val)
{
        u8 data[5];
        u32 low;
        int err;

        /* 40-bit register read */
        err = i2c_smbus_read_i2c_block_data(client, reg, 5, data);
        if (err < 0)
                return err;
        if (err != 5)
                return -EIO;
        low = (data[1] << 24) | (data[2] << 16) | (data[3] << 8) | data[4];
        *val = ((long long)data[0] << 32) | low;

        return 0;
}

static int ina238_read_field_s20(const struct i2c_client *client, u8 reg, s32 *val)
{
        u32 regval;
        int err;

        err = ina238_read_reg24(client, reg, &regval);
        if (err)
                return err;

        /* bits 3-0 Reserved, always zero */
        regval >>= 4;

        *val = sign_extend32(regval, 19);

        return 0;
}

static int ina228_read_voltage(struct ina238_data *data, int channel, long *val)
{
        int reg = channel ? INA238_BUS_VOLTAGE : INA238_CURRENT;
        u32 lsb = data->voltage_lsb[channel];
        u32 factor = NUNIT_PER_MUNIT;
        int err, regval;

        if (data->config->has_20bit_voltage_current) {
                err = ina238_read_field_s20(data->client, reg, &regval);
                if (err)
                        return err;
                /* Adjust accuracy: LSB in units of 500 pV */
                lsb /= 8;
                factor *= 2;
        } else {
                err = regmap_read(data->regmap, reg, &regval);
                if (err)
                        return err;
                regval = (s16)regval;
        }

        *val = DIV_S64_ROUND_CLOSEST((s64)regval * lsb, factor);
        return 0;
}

static int ina238_read_in(struct device *dev, u32 attr, int channel,
                          long *val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        int reg, mask = 0;
        int regval;
        int err;

        if (attr == hwmon_in_input)
                return ina228_read_voltage(data, channel, val);

        switch (channel) {
        case 0:
                switch (attr) {
                case hwmon_in_max:
                        reg = INA238_SHUNT_OVER_VOLTAGE;
                        break;
                case hwmon_in_min:
                        reg = INA238_SHUNT_UNDER_VOLTAGE;
                        break;
                case hwmon_in_max_alarm:
                        reg = INA238_DIAG_ALERT;
                        mask = INA238_DIAG_ALERT_SHNTOL;
                        break;
                case hwmon_in_min_alarm:
                        reg = INA238_DIAG_ALERT;
                        mask = INA238_DIAG_ALERT_SHNTUL;
                        break;
                default:
                        return -EOPNOTSUPP;
                }
                break;
        case 1:
                switch (attr) {
                case hwmon_in_max:
                        reg = INA238_BUS_OVER_VOLTAGE;
                        break;
                case hwmon_in_min:
                        reg = INA238_BUS_UNDER_VOLTAGE;
                        break;
                case hwmon_in_max_alarm:
                        reg = INA238_DIAG_ALERT;
                        mask = INA238_DIAG_ALERT_BUSOL;
                        break;
                case hwmon_in_min_alarm:
                        reg = INA238_DIAG_ALERT;
                        mask = INA238_DIAG_ALERT_BUSUL;
                        break;
                default:
                        return -EOPNOTSUPP;
                }
                break;
        default:
                return -EOPNOTSUPP;
        }

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

        if (mask)
                *val = !!(regval & mask);
        else
                *val = DIV_S64_ROUND_CLOSEST((s64)(s16)regval * data->voltage_lsb[channel],
                                             NUNIT_PER_MUNIT);

        return 0;
}

static int ina238_write_in(struct device *dev, u32 attr, int channel, long val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        static const int low_limits[2] = {-164, 0};
        static const int high_limits[2] = {164, 150000};
        static const u8 low_regs[2] = {INA238_SHUNT_UNDER_VOLTAGE, INA238_BUS_UNDER_VOLTAGE};
        static const u8 high_regs[2] = {INA238_SHUNT_OVER_VOLTAGE, INA238_BUS_OVER_VOLTAGE};
        int regval;

        /* Initial clamp to avoid overflows */
        val = clamp_val(val, low_limits[channel], high_limits[channel]);
        val = DIV_S64_ROUND_CLOSEST((s64)val * NUNIT_PER_MUNIT, data->voltage_lsb[channel]);
        /* Final clamp to register limits */
        regval = clamp_val(val, S16_MIN, S16_MAX) & 0xffff;

        switch (attr) {
        case hwmon_in_min:
                return regmap_write(data->regmap, low_regs[channel], regval);
        case hwmon_in_max:
                return regmap_write(data->regmap, high_regs[channel], regval);
        default:
                return -EOPNOTSUPP;
        }
}

static int __ina238_read_curr(struct ina238_data *data, long *val)
{
        u32 lsb = data->current_lsb;
        int err, regval;

        if (data->config->has_20bit_voltage_current) {
                err = ina238_read_field_s20(data->client, INA238_CURRENT, &regval);
                if (err)
                        return err;
                lsb /= 16;      /* Adjust accuracy */
        } else {
                err = regmap_read(data->regmap, INA238_CURRENT, &regval);
                if (err)
                        return err;
                regval = (s16)regval;
        }

        *val = DIV_S64_ROUND_CLOSEST((s64)regval * lsb, 1000);
        return 0;
}

static int ina238_read_curr(struct device *dev, u32 attr, long *val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        int reg, mask = 0;
        int regval;
        int err;

        if (attr == hwmon_curr_input)
                return __ina238_read_curr(data, val);

        switch (attr) {
        case hwmon_curr_min:
                reg = INA238_SHUNT_UNDER_VOLTAGE;
                break;
        case hwmon_curr_min_alarm:
                reg = INA238_DIAG_ALERT;
                mask = INA238_DIAG_ALERT_SHNTUL;
                break;
        case hwmon_curr_max:
                reg = INA238_SHUNT_OVER_VOLTAGE;
                break;
        case hwmon_curr_max_alarm:
                reg = INA238_DIAG_ALERT;
                mask = INA238_DIAG_ALERT_SHNTOL;
                break;
        default:
                return -EOPNOTSUPP;
        }

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

        if (mask)
                *val = !!(regval & mask);
        else
                *val = DIV_S64_ROUND_CLOSEST((s64)(s16)regval * data->current_lsb, 1000);

        return 0;
}

static int ina238_write_curr(struct device *dev, u32 attr, long val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        int regval;

        /* Set baseline range to avoid over/underflows */
        val = clamp_val(val, -1000000, 1000000);
        /* Scale */
        val = DIV_ROUND_CLOSEST(val * 1000, data->current_lsb);
        /* Clamp to register size */
        regval = clamp_val(val, S16_MIN, S16_MAX) & 0xffff;

        switch (attr) {
        case hwmon_curr_min:
                return regmap_write(data->regmap, INA238_SHUNT_UNDER_VOLTAGE,
                                    regval);
        case hwmon_curr_max:
                return regmap_write(data->regmap, INA238_SHUNT_OVER_VOLTAGE,
                                    regval);
        default:
                return -EOPNOTSUPP;
        }
}

static int ina238_read_power(struct device *dev, u32 attr, long *val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        long long power;
        int regval;
        int err;

        switch (attr) {
        case hwmon_power_input:
                err = ina238_read_reg24(data->client, INA238_POWER, &regval);
                if (err)
                        return err;

                power = (long long)regval * data->power_lsb;
                /* Clamp value to maximum value of long */
                *val = clamp_val(power, 0, LONG_MAX);
                break;
        case hwmon_power_input_highest:
                err = ina238_read_reg24(data->client, SQ52206_POWER_PEAK, &regval);
                if (err)
                        return err;

                power = (long long)regval * data->power_lsb;
                /* Clamp value to maximum value of long */
                *val = clamp_val(power, 0, LONG_MAX);
                break;
        case hwmon_power_max:
                err = regmap_read(data->regmap, INA238_POWER_LIMIT, &regval);
                if (err)
                        return err;

                /*
                 * Truncated 24-bit compare register, lower 8-bits are
                 * truncated. Same conversion to/from uW as POWER register.
                 */
                power = ((long long)regval << 8) * data->power_lsb;
                /* Clamp value to maximum value of long */
                *val = clamp_val(power, 0, LONG_MAX);
                break;
        case hwmon_power_max_alarm:
                err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
                if (err)
                        return err;

                *val = !!(regval & INA238_DIAG_ALERT_POL);
                break;
        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

static int ina238_write_power_max(struct device *dev, long val)
{
        struct ina238_data *data = dev_get_drvdata(dev);

        /*
         * Unsigned postive values. Compared against the 24-bit power register,
         * lower 8-bits are truncated. Same conversion to/from uW as POWER
         * register.
         * The first clamp_val() is to establish a baseline to avoid overflows.
         */
        val = clamp_val(val, 0, LONG_MAX / 2);
        val = DIV_ROUND_CLOSEST(val, data->power_lsb);
        val = clamp_val(val >> 8, 0, U16_MAX);

        return regmap_write(data->regmap, INA238_POWER_LIMIT, val);
}

static int ina238_temp_from_reg(s16 regval, u8 resolution)
{
        return ((regval >> (16 - resolution)) * 1000) >> (resolution - 9);
}

static int ina238_read_temp(struct device *dev, u32 attr, long *val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        int regval;
        int err;

        switch (attr) {
        case hwmon_temp_input:
                err = regmap_read(data->regmap, INA238_DIE_TEMP, &regval);
                if (err)
                        return err;
                *val = ina238_temp_from_reg(regval, data->config->temp_resolution);
                break;
        case hwmon_temp_max:
                err = regmap_read(data->regmap, INA238_TEMP_LIMIT, &regval);
                if (err)
                        return err;
                /* Signed, result in mC */
                *val = ina238_temp_from_reg(regval, data->config->temp_resolution);
                break;
        case hwmon_temp_max_alarm:
                err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
                if (err)
                        return err;

                *val = !!(regval & INA238_DIAG_ALERT_TMPOL);
                break;
        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

static u16 ina238_temp_to_reg(long val, u8 resolution)
{
        int fraction = 1000 - DIV_ROUND_CLOSEST(1000, BIT(resolution - 9));

        val = clamp_val(val, -255000 - fraction, 255000 + fraction);

        return (DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution)) & 0xffff;
}

static int ina238_write_temp_max(struct device *dev, long val)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        int regval;

        regval = ina238_temp_to_reg(val, data->config->temp_resolution);
        return regmap_write(data->regmap, INA238_TEMP_LIMIT, regval);
}

static int ina238_read_energy(struct device *dev, s64 *energy)
{
        struct ina238_data *data = dev_get_drvdata(dev);
        u64 regval;
        int ret;

        ret = ina238_read_reg40(data->client, SQ52206_ENERGY, &regval);
        if (ret)
                return ret;

        /* result in uJ */
        *energy = regval * data->energy_lsb;
        return 0;
}

static int ina238_read(struct device *dev, enum hwmon_sensor_types type,
                       u32 attr, int channel, long *val)
{
        switch (type) {
        case hwmon_in:
                return ina238_read_in(dev, attr, channel, val);
        case hwmon_curr:
                return ina238_read_curr(dev, attr, val);
        case hwmon_power:
                return ina238_read_power(dev, attr, val);
        case hwmon_energy64:
                return ina238_read_energy(dev, (s64 *)val);
        case hwmon_temp:
                return ina238_read_temp(dev, attr, val);
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int ina238_write(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long val)
{
        switch (type) {
        case hwmon_in:
                return ina238_write_in(dev, attr, channel, val);
        case hwmon_curr:
                return ina238_write_curr(dev, attr, val);
        case hwmon_power:
                return ina238_write_power_max(dev, val);
        case hwmon_temp:
                return ina238_write_temp_max(dev, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t ina238_is_visible(const void *drvdata,
                                 enum hwmon_sensor_types type,
                                 u32 attr, int channel)
{
        const struct ina238_data *data = drvdata;
        bool has_power_highest = data->config->has_power_highest;
        bool has_energy = data->config->has_energy;

        switch (type) {
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                case hwmon_in_max_alarm:
                case hwmon_in_min_alarm:
                        return 0444;
                case hwmon_in_max:
                case hwmon_in_min:
                        return 0644;
                default:
                        return 0;
                }
        case hwmon_curr:
                switch (attr) {
                case hwmon_curr_input:
                case hwmon_curr_max_alarm:
                case hwmon_curr_min_alarm:
                        return 0444;
                case hwmon_curr_max:
                case hwmon_curr_min:
                        return 0644;
                default:
                        return 0;
                }
        case hwmon_power:
                switch (attr) {
                case hwmon_power_input:
                case hwmon_power_max_alarm:
                        return 0444;
                case hwmon_power_max:
                        return 0644;
                case hwmon_power_input_highest:
                        if (has_power_highest)
                                return 0444;
                        return 0;
                default:
                        return 0;
                }
        case hwmon_energy64:
                /* hwmon_energy_input */
                if (has_energy)
                        return 0444;
                return 0;
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                case hwmon_temp_max_alarm:
                        return 0444;
                case hwmon_temp_max:
                        return 0644;
                default:
                        return 0;
                }
        default:
                return 0;
        }
}

#define INA238_HWMON_IN_CONFIG (HWMON_I_INPUT | \
                                HWMON_I_MAX | HWMON_I_MAX_ALARM | \
                                HWMON_I_MIN | HWMON_I_MIN_ALARM)

static const struct hwmon_channel_info * const ina238_info[] = {
        HWMON_CHANNEL_INFO(in,
                           /* 0: shunt voltage */
                           INA238_HWMON_IN_CONFIG,
                           /* 1: bus voltage */
                           INA238_HWMON_IN_CONFIG),
        HWMON_CHANNEL_INFO(curr,
                           /* 0: current through shunt */
                           HWMON_C_INPUT | HWMON_C_MIN | HWMON_C_MIN_ALARM |
                           HWMON_C_MAX | HWMON_C_MAX_ALARM),
        HWMON_CHANNEL_INFO(power,
                           /* 0: power */
                           HWMON_P_INPUT | HWMON_P_MAX |
                           HWMON_P_MAX_ALARM | HWMON_P_INPUT_HIGHEST),
        HWMON_CHANNEL_INFO(energy64,
                           HWMON_E_INPUT),
        HWMON_CHANNEL_INFO(temp,
                           /* 0: die temperature */
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_ALARM),
        NULL
};

static const struct hwmon_ops ina238_hwmon_ops = {
        .is_visible = ina238_is_visible,
        .read = ina238_read,
        .write = ina238_write,
};

static const struct hwmon_chip_info ina238_chip_info = {
        .ops = &ina238_hwmon_ops,
        .info = ina238_info,
};

static int ina238_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct ina238_data *data;
        enum ina238_ids chip;
        int config;
        int ret;

        chip = (uintptr_t)i2c_get_match_data(client);

        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->client = client;
        /* set the device type */
        data->config = &ina238_config[chip];

        data->regmap = devm_regmap_init_i2c(client, &ina238_regmap_config);
        if (IS_ERR(data->regmap)) {
                dev_err(dev, "failed to allocate register map\n");
                return PTR_ERR(data->regmap);
        }

        /* Setup CONFIG register */
        config = data->config->config_default;
        if (data->config->current_lsb) {
                data->voltage_lsb[0] = INA238_SHUNT_VOLTAGE_LSB;
                data->current_lsb = data->config->current_lsb;
        } else {
                /* load shunt value */
                if (device_property_read_u32(dev, "shunt-resistor", &data->rshunt) < 0)
                        data->rshunt = INA238_RSHUNT_DEFAULT;
                if (data->rshunt == 0) {
                        dev_err(dev, "invalid shunt resister value %u\n", data->rshunt);
                        return -EINVAL;
                }

                /* load shunt gain value */
                if (device_property_read_u32(dev, "ti,shunt-gain", &data->gain) < 0)
                        data->gain = 4; /* Default of ADCRANGE = 0 */
                if (data->gain != 1 && data->gain != 2 && data->gain != 4) {
                        dev_err(dev, "invalid shunt gain value %u\n", data->gain);
                        return -EINVAL;
                }

                /* Setup SHUNT_CALIBRATION register with fixed value */
                ret = regmap_write(data->regmap, INA238_SHUNT_CALIBRATION,
                                   INA238_CALIBRATION_VALUE);
                if (ret < 0) {
                        dev_err(dev, "error configuring the device: %d\n", ret);
                        return -ENODEV;
                }
                if (chip == sq52206) {
                        if (data->gain == 1)            /* ADCRANGE = 10/11 is /1 */
                                config |= SQ52206_CONFIG_ADCRANGE_HIGH;
                        else if (data->gain == 2)       /* ADCRANGE = 01 is /2 */
                                config |= SQ52206_CONFIG_ADCRANGE_LOW;
                } else if (data->gain == 1) {           /* ADCRANGE = 1 is /1 */
                        config |= INA238_CONFIG_ADCRANGE;
                }
                data->voltage_lsb[0] = INA238_SHUNT_VOLTAGE_LSB * data->gain / 4;
                data->current_lsb = DIV_U64_ROUND_CLOSEST(250ULL * INA238_FIXED_SHUNT * data->gain,
                                                          data->rshunt);
        }

        ret = regmap_write(data->regmap, INA238_CONFIG, config);
        if (ret < 0) {
                dev_err(dev, "error configuring the device: %d\n", ret);
                return -ENODEV;
        }

        /* Setup ADC_CONFIG register */
        ret = regmap_write(data->regmap, INA238_ADC_CONFIG,
                           INA238_ADC_CONFIG_DEFAULT);
        if (ret < 0) {
                dev_err(dev, "error configuring the device: %d\n", ret);
                return -ENODEV;
        }

        /* Setup alert/alarm configuration */
        config = INA238_DIAG_ALERT_DEFAULT;
        if (device_property_read_bool(dev, "ti,alert-polarity-active-high"))
                config |= INA238_DIAG_ALERT_APOL;

        ret = regmap_write(data->regmap, INA238_DIAG_ALERT, config);
        if (ret < 0) {
                dev_err(dev, "error configuring the device: %d\n", ret);
                return -ENODEV;
        }

        data->voltage_lsb[1] = data->config->bus_voltage_lsb;

        data->power_lsb = DIV_ROUND_CLOSEST(data->current_lsb *
                                            data->config->power_calculate_factor,
                                            100);

        data->energy_lsb = data->power_lsb * 16;

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
                                                         &ina238_chip_info, NULL);
        if (IS_ERR(hwmon_dev))
                return PTR_ERR(hwmon_dev);

        if (data->rshunt)
                dev_info(dev, "power monitor %s (Rshunt = %u uOhm, gain = %u)\n",
                         client->name, data->rshunt, data->gain);

        return 0;
}

static const struct i2c_device_id ina238_id[] = {
        { "ina228", ina228 },
        { "ina237", ina237 },
        { "ina238", ina238 },
        { "ina700", ina700 },
        { "ina780", ina780 },
        { "sq52206", sq52206 },
        { }
};
MODULE_DEVICE_TABLE(i2c, ina238_id);

static const struct of_device_id __maybe_unused ina238_of_match[] = {
        {
                .compatible = "ti,ina228",
                .data = (void *)ina228
        },
        {
                .compatible = "ti,ina237",
                .data = (void *)ina237
        },
        {
                .compatible = "ti,ina238",
                .data = (void *)ina238
        },
        {
                .compatible = "ti,ina700",
                .data = (void *)ina700
        },
        {
                .compatible = "ti,ina780",
                .data = (void *)ina780
        },
        {
                .compatible = "silergy,sq52206",
                .data = (void *)sq52206
        },
        { }
};
MODULE_DEVICE_TABLE(of, ina238_of_match);

static struct i2c_driver ina238_driver = {
        .driver = {
                .name   = "ina238",
                .of_match_table = of_match_ptr(ina238_of_match),
        },
        .probe          = ina238_probe,
        .id_table       = ina238_id,
};

module_i2c_driver(ina238_driver);

MODULE_AUTHOR("Nathan Rossi <nathan.rossi@digi.com>");
MODULE_DESCRIPTION("ina238 driver");
MODULE_LICENSE("GPL");