// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Texas Instruments INA219, INA226 power monitor chips
 *
 * INA219:
 * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
 * Datasheet: https://www.ti.com/product/ina219
 *
 * INA220:
 * Bi-Directional Current/Power Monitor with I2C Interface
 * Datasheet: https://www.ti.com/product/ina220
 *
 * INA226:
 * Bi-Directional Current/Power Monitor with I2C Interface
 * Datasheet: https://www.ti.com/product/ina226
 *
 * INA230:
 * Bi-directional Current/Power Monitor with I2C Interface
 * Datasheet: https://www.ti.com/product/ina230
 *
 * Copyright (C) 2012 Lothar Felten <lothar.felten@gmail.com>
 * Thanks to Jan Volkering
 */

#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/device.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/property.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/util_macros.h>

/* common register definitions */
#define INA2XX_CONFIG                   0x00
#define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
#define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
#define INA2XX_POWER                    0x03 /* readonly */
#define INA2XX_CURRENT                  0x04 /* readonly */
#define INA2XX_CALIBRATION              0x05

/* INA226 register definitions */
#define INA226_MASK_ENABLE              0x06
#define INA226_ALERT_LIMIT              0x07
#define INA226_DIE_ID                   0xFF

/* SY24655 register definitions */
#define SY24655_EIN                             0x0A
#define SY24655_ACCUM_CONFIG    0x0D
#define INA2XX_MAX_REGISTERS            0x0D

/* settings - depend on use case */
#define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
#define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
#define INA260_CONFIG_DEFAULT           0x6527  /* averages=16 */
#define SY24655_CONFIG_DEFAULT          0x4527  /* averages=16 */

/* (only for sy24655) */
#define SY24655_ACCUM_CONFIG_DEFAULT    0x044C  /* continuous mode, clear after read*/

/* worst case is 68.10 ms (~14.6Hz, ina219) */
#define INA2XX_CONVERSION_RATE          15
#define INA2XX_MAX_DELAY                69 /* worst case delay in ms */

#define INA2XX_RSHUNT_DEFAULT           10000
#define INA260_RSHUNT                   2000

/* bit mask for reading the averaging setting in the configuration register */
#define INA226_AVG_RD_MASK              GENMASK(11, 9)

#define INA226_READ_AVG(reg)            FIELD_GET(INA226_AVG_RD_MASK, reg)

#define INA226_ALERT_LATCH_ENABLE       BIT(0)
#define INA226_ALERT_POLARITY           BIT(1)

/* bit number of alert functions in Mask/Enable Register */
#define INA226_SHUNT_OVER_VOLTAGE_MASK  BIT(15)
#define INA226_SHUNT_UNDER_VOLTAGE_MASK BIT(14)
#define INA226_BUS_OVER_VOLTAGE_MASK    BIT(13)
#define INA226_BUS_UNDER_VOLTAGE_MASK   BIT(12)
#define INA226_POWER_OVER_LIMIT_MASK    BIT(11)

/* bit mask for alert config bits of Mask/Enable Register */
#define INA226_ALERT_CONFIG_MASK        GENMASK(15, 10)
#define INA226_ALERT_FUNCTION_FLAG      BIT(4)

/*
 * Both bus voltage and shunt voltage conversion times for ina226 are set
 * to 0b0100 on POR, which translates to 2200 microseconds in total.
 */
#define INA226_TOTAL_CONV_TIME_DEFAULT  2200

static bool ina2xx_writeable_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case INA2XX_CONFIG:
        case INA2XX_CALIBRATION:
        case INA226_MASK_ENABLE:
        case INA226_ALERT_LIMIT:
        case SY24655_ACCUM_CONFIG:
                return true;
        default:
                return false;
        }
}

static bool ina2xx_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case INA2XX_SHUNT_VOLTAGE:
        case INA2XX_BUS_VOLTAGE:
        case INA2XX_POWER:
        case INA2XX_CURRENT:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config ina2xx_regmap_config = {
        .reg_bits = 8,
        .val_bits = 16,
        .use_single_write = true,
        .use_single_read = true,
        .max_register = INA2XX_MAX_REGISTERS,
        .cache_type = REGCACHE_MAPLE,
        .volatile_reg = ina2xx_volatile_reg,
        .writeable_reg = ina2xx_writeable_reg,
};

enum ina2xx_ids { ina219, ina226, ina260, sy24655 };

struct ina2xx_config {
        u16 config_default;
        bool has_alerts;        /* chip supports alerts and limits */
        bool has_ishunt;        /* chip has internal shunt resistor */
        bool has_power_average; /* chip has internal shunt resistor */
        int calibration_value;
        int shunt_div;
        int bus_voltage_shift;
        int bus_voltage_lsb;    /* uV */
        int power_lsb_factor;
};

struct ina2xx_data {
        const struct ina2xx_config *config;
        enum ina2xx_ids chip;

        long rshunt;
        long current_lsb_uA;
        long power_lsb_uW;
        struct regmap *regmap;
        struct i2c_client *client;
};

static const struct ina2xx_config ina2xx_config[] = {
        [ina219] = {
                .config_default = INA219_CONFIG_DEFAULT,
                .calibration_value = 4096,
                .shunt_div = 100,
                .bus_voltage_shift = 3,
                .bus_voltage_lsb = 4000,
                .power_lsb_factor = 20,
                .has_alerts = false,
                .has_ishunt = false,
                .has_power_average = false,
        },
        [ina226] = {
                .config_default = INA226_CONFIG_DEFAULT,
                .calibration_value = 2048,
                .shunt_div = 400,
                .bus_voltage_shift = 0,
                .bus_voltage_lsb = 1250,
                .power_lsb_factor = 25,
                .has_alerts = true,
                .has_ishunt = false,
                .has_power_average = false,
        },
        [ina260] = {
                .config_default = INA260_CONFIG_DEFAULT,
                .shunt_div = 400,
                .bus_voltage_shift = 0,
                .bus_voltage_lsb = 1250,
                .power_lsb_factor = 8,
                .has_alerts = true,
                .has_ishunt = true,
                .has_power_average = false,
        },
        [sy24655] = {
                .config_default = SY24655_CONFIG_DEFAULT,
                .calibration_value = 4096,
                .shunt_div = 400,
                .bus_voltage_shift = 0,
                .bus_voltage_lsb = 1250,
                .power_lsb_factor = 25,
                .has_alerts = true,
                .has_ishunt = false,
                .has_power_average = true,
        },
};

/*
 * Available averaging rates for ina226. The indices correspond with
 * the bit values expected by the chip (according to the ina226 datasheet,
 * table 3 AVG bit settings, found at
 * https://www.ti.com/lit/ds/symlink/ina226.pdf.
 */
static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };

static int ina226_reg_to_interval(u16 config)
{
        int avg = ina226_avg_tab[INA226_READ_AVG(config)];

        /*
         * Multiply the total conversion time by the number of averages.
         * Return the result in milliseconds.
         */
        return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
}

/*
 * Return the new, shifted AVG field value of CONFIG register,
 * to use with regmap_update_bits
 */
static u16 ina226_interval_to_reg(long interval)
{
        int avg, avg_bits;

        /*
         * The maximum supported interval is 1,024 * (2 * 8.244ms) ~= 16.8s.
         * Clamp to 32 seconds before calculations to avoid overflows.
         */
        interval = clamp_val(interval, 0, 32000);

        avg = DIV_ROUND_CLOSEST(interval * 1000,
                                INA226_TOTAL_CONV_TIME_DEFAULT);
        avg_bits = find_closest(avg, ina226_avg_tab,
                                ARRAY_SIZE(ina226_avg_tab));

        return FIELD_PREP(INA226_AVG_RD_MASK, avg_bits);
}

static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
                            unsigned int regval)
{
        int val;

        switch (reg) {
        case INA2XX_SHUNT_VOLTAGE:
                /* signed register */
                val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
                break;
        case INA2XX_BUS_VOLTAGE:
                val = (regval >> data->config->bus_voltage_shift) *
                  data->config->bus_voltage_lsb;
                val = DIV_ROUND_CLOSEST(val, 1000);
                break;
        case INA2XX_POWER:
                val = regval * data->power_lsb_uW;
                break;
        case INA2XX_CURRENT:
                /* signed register, result in mA */
                val = (s16)regval * data->current_lsb_uA;
                val = DIV_ROUND_CLOSEST(val, 1000);
                break;
        case INA2XX_CALIBRATION:
                val = regval;
                break;
        default:
                /* programmer goofed */
                WARN_ON_ONCE(1);
                val = 0;
                break;
        }

        return val;
}

/*
 * Read and convert register value from chip. If the register value is 0,
 * check if the chip has been power cycled or reset. If so, re-initialize it.
 */
static int ina2xx_read_init(struct device *dev, int reg, long *val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);
        struct regmap *regmap = data->regmap;
        unsigned int regval;
        int ret, retry;

        if (data->config->has_ishunt) {
                /* No calibration needed */
                ret = regmap_read(regmap, reg, &regval);
                if (ret < 0)
                        return ret;
                *val = ina2xx_get_value(data, reg, regval);
                return 0;
        }

        for (retry = 5; retry; retry--) {
                ret = regmap_read(regmap, reg, &regval);
                if (ret < 0)
                        return ret;

                /*
                 * If the current value in the calibration register is 0, the
                 * power and current registers will also remain at 0. In case
                 * the chip has been reset let's check the calibration
                 * register and reinitialize if needed.
                 * We do that extra read of the calibration register if there
                 * is some hint of a chip reset.
                 */
                if (regval == 0) {
                        unsigned int cal;

                        ret = regmap_read_bypassed(regmap, INA2XX_CALIBRATION, &cal);
                        if (ret < 0)
                                return ret;

                        if (cal == 0) {
                                dev_warn(dev, "chip not calibrated, reinitializing\n");

                                regcache_mark_dirty(regmap);
                                regcache_sync(regmap);

                                /*
                                 * Let's make sure the power and current
                                 * registers have been updated before trying
                                 * again.
                                 */
                                msleep(INA2XX_MAX_DELAY);
                                continue;
                        }
                }
                *val = ina2xx_get_value(data, reg, regval);
                return 0;
        }

        /*
         * If we're here then although all write operations succeeded, the
         * chip still returns 0 in the calibration register. Nothing more we
         * can do here.
         */
        dev_err(dev, "unable to reinitialize the chip\n");
        return -ENODEV;
}

/*
 * Turns alert limit values into register values.
 * Opposite of the formula in ina2xx_get_value().
 */
static u16 ina226_alert_to_reg(struct ina2xx_data *data, int reg, long val)
{
        switch (reg) {
        case INA2XX_SHUNT_VOLTAGE:
                val = clamp_val(val, 0, SHRT_MAX * data->config->shunt_div);
                val *= data->config->shunt_div;
                return clamp_val(val, 0, SHRT_MAX);
        case INA2XX_BUS_VOLTAGE:
                val = clamp_val(val, 0, 200000);
                val = (val * 1000) << data->config->bus_voltage_shift;
                val = DIV_ROUND_CLOSEST(val, data->config->bus_voltage_lsb);
                return clamp_val(val, 0, USHRT_MAX);
        case INA2XX_POWER:
                val = clamp_val(val, 0, UINT_MAX - data->power_lsb_uW);
                val = DIV_ROUND_CLOSEST(val, data->power_lsb_uW);
                return clamp_val(val, 0, USHRT_MAX);
        case INA2XX_CURRENT:
                val = clamp_val(val, INT_MIN / 1000, INT_MAX / 1000);
                /* signed register, result in mA */
                val = DIV_ROUND_CLOSEST(val * 1000, data->current_lsb_uA);
                return clamp_val(val, SHRT_MIN, SHRT_MAX);
        default:
                /* programmer goofed */
                WARN_ON_ONCE(1);
                return 0;
        }
}

static int ina226_alert_limit_read(struct ina2xx_data *data, u32 mask, int reg, long *val)
{
        struct regmap *regmap = data->regmap;
        int regval;
        int ret;

        ret = regmap_read(regmap, INA226_MASK_ENABLE, &regval);
        if (ret)
                return ret;

        if (regval & mask) {
                ret = regmap_read(regmap, INA226_ALERT_LIMIT, &regval);
                if (ret)
                        return ret;
                *val = ina2xx_get_value(data, reg, regval);
        } else {
                *val = 0;
        }
        return 0;
}

static int ina226_alert_limit_write(struct ina2xx_data *data, u32 mask, int reg, long val)
{
        struct regmap *regmap = data->regmap;
        int ret;

        if (val < 0)
                return -EINVAL;

        /*
         * Clear all alerts first to avoid accidentally triggering ALERT pin
         * due to register write sequence. Then, only enable the alert
         * if the value is non-zero.
         */
        ret = regmap_update_bits(regmap, INA226_MASK_ENABLE,
                                 INA226_ALERT_CONFIG_MASK, 0);
        if (ret < 0)
                return ret;

        ret = regmap_write(regmap, INA226_ALERT_LIMIT,
                           ina226_alert_to_reg(data, reg, val));
        if (ret < 0)
                return ret;

        if (val)
                return regmap_update_bits(regmap, INA226_MASK_ENABLE,
                                          INA226_ALERT_CONFIG_MASK, mask);
        return 0;
}

static int ina2xx_chip_read(struct device *dev, u32 attr, long *val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);
        u32 regval;
        int ret;

        switch (attr) {
        case hwmon_chip_update_interval:
                ret = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
                if (ret)
                        return ret;

                *val = ina226_reg_to_interval(regval);
                break;
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int ina226_alert_read(struct regmap *regmap, u32 mask, long *val)
{
        unsigned int regval;
        int ret;

        ret = regmap_read_bypassed(regmap, INA226_MASK_ENABLE, &regval);
        if (ret)
                return ret;

        *val = (regval & mask) && (regval & INA226_ALERT_FUNCTION_FLAG);

        return 0;
}

static int ina2xx_in_read(struct device *dev, u32 attr, int channel, long *val)
{
        int voltage_reg = channel ? INA2XX_BUS_VOLTAGE : INA2XX_SHUNT_VOLTAGE;
        u32 under_voltage_mask = channel ? INA226_BUS_UNDER_VOLTAGE_MASK
                                         : INA226_SHUNT_UNDER_VOLTAGE_MASK;
        u32 over_voltage_mask = channel ? INA226_BUS_OVER_VOLTAGE_MASK
                                        : INA226_SHUNT_OVER_VOLTAGE_MASK;
        struct ina2xx_data *data = dev_get_drvdata(dev);
        struct regmap *regmap = data->regmap;
        unsigned int regval;
        int ret;

        switch (attr) {
        case hwmon_in_input:
                ret = regmap_read(regmap, voltage_reg, &regval);
                if (ret)
                        return ret;
                *val = ina2xx_get_value(data, voltage_reg, regval);
                break;
        case hwmon_in_lcrit:
                return ina226_alert_limit_read(data, under_voltage_mask,
                                               voltage_reg, val);
        case hwmon_in_crit:
                return ina226_alert_limit_read(data, over_voltage_mask,
                                               voltage_reg, val);
        case hwmon_in_lcrit_alarm:
                return ina226_alert_read(regmap, under_voltage_mask, val);
        case hwmon_in_crit_alarm:
                return ina226_alert_read(regmap, over_voltage_mask, val);
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

/*
 * Configuring the READ_EIN (bit 10) of the ACCUM_CONFIG register to 1
 * can clear accumulator and sample_count after reading the EIN register.
 * This way, the average power between the last read and the current
 * read can be obtained. By combining with accurate time data from
 * outside, the energy consumption during that period can be calculated.
 */
static int sy24655_average_power_read(struct ina2xx_data *data, u8 reg, long *val)
{
        u8 template[6];
        int ret;
        long accumulator_24, sample_count;

        /* 48-bit register read */
        ret = i2c_smbus_read_i2c_block_data(data->client, reg, 6, template);
        if (ret < 0)
                return ret;
        if (ret != 6)
                return -EIO;
        accumulator_24 = ((template[3] << 16) |
                                (template[4] << 8) |
                                template[5]);
        sample_count = ((template[0] << 16) |
                                (template[1] << 8) |
                                template[2]);
        if (sample_count <= 0) {
                *val = 0;
                return 0;
        }

        *val = DIV_ROUND_CLOSEST(accumulator_24, sample_count) * data->power_lsb_uW;

        return 0;
}

static int ina2xx_power_read(struct device *dev, u32 attr, long *val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_power_input:
                return ina2xx_read_init(dev, INA2XX_POWER, val);
        case hwmon_power_average:
                return sy24655_average_power_read(data, SY24655_EIN, val);
        case hwmon_power_crit:
                return ina226_alert_limit_read(data, INA226_POWER_OVER_LIMIT_MASK,
                                               INA2XX_POWER, val);
        case hwmon_power_crit_alarm:
                return ina226_alert_read(data->regmap, INA226_POWER_OVER_LIMIT_MASK, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int ina2xx_curr_read(struct device *dev, u32 attr, long *val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);
        struct regmap *regmap = data->regmap;
        unsigned int regval;
        int ret;

        /*
         * While the chips supported by this driver do not directly support
         * current limits, they do support setting shunt voltage limits.
         * The shunt voltage divided by the shunt resistor value is the current.
         * On top of that, calibration values are set such that in the shunt
         * voltage register and the current register report the same values.
         * That means we can report and configure current limits based on shunt
         * voltage limits.
         */
        switch (attr) {
        case hwmon_curr_input:
                /*
                 * Since the shunt voltage and the current register report the
                 * same values when the chip is calibrated, we can calculate
                 * the current directly from the shunt voltage without relying
                 * on chip calibration.
                 */
                ret = regmap_read(regmap, INA2XX_SHUNT_VOLTAGE, &regval);
                if (ret)
                        return ret;
                *val = ina2xx_get_value(data, INA2XX_CURRENT, regval);
                return 0;
        case hwmon_curr_lcrit:
                return ina226_alert_limit_read(data, INA226_SHUNT_UNDER_VOLTAGE_MASK,
                                               INA2XX_CURRENT, val);
        case hwmon_curr_crit:
                return ina226_alert_limit_read(data, INA226_SHUNT_OVER_VOLTAGE_MASK,
                                               INA2XX_CURRENT, val);
        case hwmon_curr_lcrit_alarm:
                return ina226_alert_read(regmap, INA226_SHUNT_UNDER_VOLTAGE_MASK, val);
        case hwmon_curr_crit_alarm:
                return ina226_alert_read(regmap, INA226_SHUNT_OVER_VOLTAGE_MASK, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int ina2xx_read(struct device *dev, enum hwmon_sensor_types type,
                       u32 attr, int channel, long *val)
{
        switch (type) {
        case hwmon_chip:
                return ina2xx_chip_read(dev, attr, val);
        case hwmon_in:
                return ina2xx_in_read(dev, attr, channel, val);
        case hwmon_power:
                return ina2xx_power_read(dev, attr, val);
        case hwmon_curr:
                return ina2xx_curr_read(dev, attr, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int ina2xx_chip_write(struct device *dev, u32 attr, long val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_chip_update_interval:
                return regmap_update_bits(data->regmap, INA2XX_CONFIG,
                                          INA226_AVG_RD_MASK,
                                          ina226_interval_to_reg(val));
        default:
                return -EOPNOTSUPP;
        }
}

static int ina2xx_in_write(struct device *dev, u32 attr, int channel, long val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_in_lcrit:
                return ina226_alert_limit_write(data,
                        channel ? INA226_BUS_UNDER_VOLTAGE_MASK : INA226_SHUNT_UNDER_VOLTAGE_MASK,
                        channel ? INA2XX_BUS_VOLTAGE : INA2XX_SHUNT_VOLTAGE,
                        val);
        case hwmon_in_crit:
                return ina226_alert_limit_write(data,
                        channel ? INA226_BUS_OVER_VOLTAGE_MASK : INA226_SHUNT_OVER_VOLTAGE_MASK,
                        channel ? INA2XX_BUS_VOLTAGE : INA2XX_SHUNT_VOLTAGE,
                        val);
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int ina2xx_power_write(struct device *dev, u32 attr, long val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_power_crit:
                return ina226_alert_limit_write(data, INA226_POWER_OVER_LIMIT_MASK,
                                                INA2XX_POWER, val);
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int ina2xx_curr_write(struct device *dev, u32 attr, long val)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_curr_lcrit:
                return ina226_alert_limit_write(data, INA226_SHUNT_UNDER_VOLTAGE_MASK,
                                                INA2XX_CURRENT, val);
        case hwmon_curr_crit:
                return ina226_alert_limit_write(data, INA226_SHUNT_OVER_VOLTAGE_MASK,
                                                INA2XX_CURRENT, val);
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int ina2xx_write(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long val)
{
        switch (type) {
        case hwmon_chip:
                return ina2xx_chip_write(dev, attr, val);
        case hwmon_in:
                return ina2xx_in_write(dev, attr, channel, val);
        case hwmon_power:
                return ina2xx_power_write(dev, attr, val);
        case hwmon_curr:
                return ina2xx_curr_write(dev, attr, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t ina2xx_is_visible(const void *_data, enum hwmon_sensor_types type,
                                 u32 attr, int channel)
{
        const struct ina2xx_data *data = _data;
        bool has_alerts = data->config->has_alerts;
        bool has_power_average = data->config->has_power_average;
        enum ina2xx_ids chip = data->chip;

        switch (type) {
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                        return 0444;
                case hwmon_in_lcrit:
                case hwmon_in_crit:
                        if (has_alerts)
                                return 0644;
                        break;
                case hwmon_in_lcrit_alarm:
                case hwmon_in_crit_alarm:
                        if (has_alerts)
                                return 0444;
                        break;
                default:
                        break;
                }
                break;
        case hwmon_curr:
                switch (attr) {
                case hwmon_curr_input:
                        return 0444;
                case hwmon_curr_lcrit:
                case hwmon_curr_crit:
                        if (has_alerts)
                                return 0644;
                        break;
                case hwmon_curr_lcrit_alarm:
                case hwmon_curr_crit_alarm:
                        if (has_alerts)
                                return 0444;
                        break;
                default:
                        break;
                }
                break;
        case hwmon_power:
                switch (attr) {
                case hwmon_power_input:
                        return 0444;
                case hwmon_power_crit:
                        if (has_alerts)
                                return 0644;
                        break;
                case hwmon_power_crit_alarm:
                        if (has_alerts)
                                return 0444;
                        break;
                case hwmon_power_average:
                        if (has_power_average)
                                return 0444;
                        break;
                default:
                        break;
                }
                break;
        case hwmon_chip:
                switch (attr) {
                case hwmon_chip_update_interval:
                        if (chip == ina226 || chip == ina260)
                                return 0644;
                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }
        return 0;
}

static const struct hwmon_channel_info * const ina2xx_info[] = {
        HWMON_CHANNEL_INFO(chip,
                           HWMON_C_UPDATE_INTERVAL),
        HWMON_CHANNEL_INFO(in,
                           HWMON_I_INPUT | HWMON_I_CRIT | HWMON_I_CRIT_ALARM |
                           HWMON_I_LCRIT | HWMON_I_LCRIT_ALARM,
                           HWMON_I_INPUT | HWMON_I_CRIT | HWMON_I_CRIT_ALARM |
                           HWMON_I_LCRIT | HWMON_I_LCRIT_ALARM
                           ),
        HWMON_CHANNEL_INFO(curr, HWMON_C_INPUT | HWMON_C_CRIT | HWMON_C_CRIT_ALARM |
                           HWMON_C_LCRIT | HWMON_C_LCRIT_ALARM),
        HWMON_CHANNEL_INFO(power,
                           HWMON_P_INPUT | HWMON_P_CRIT | HWMON_P_CRIT_ALARM |
                           HWMON_P_AVERAGE),
        NULL
};

static const struct hwmon_ops ina2xx_hwmon_ops = {
        .is_visible = ina2xx_is_visible,
        .read = ina2xx_read,
        .write = ina2xx_write,
};

static const struct hwmon_chip_info ina2xx_chip_info = {
        .ops = &ina2xx_hwmon_ops,
        .info = ina2xx_info,
};

/* shunt resistance */

/*
 * In order to keep calibration register value fixed, the product
 * of current_lsb and shunt_resistor should also be fixed and equal
 * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
 * to keep the scale.
 */
static int ina2xx_set_shunt(struct ina2xx_data *data, unsigned long val)
{
        unsigned int dividend = DIV_ROUND_CLOSEST(1000000000,
                                                  data->config->shunt_div);
        if (!val || val > dividend)
                return -EINVAL;

        data->rshunt = val;
        data->current_lsb_uA = DIV_ROUND_CLOSEST(dividend, val);
        data->power_lsb_uW = data->config->power_lsb_factor *
                             data->current_lsb_uA;

        return 0;
}

static ssize_t shunt_resistor_show(struct device *dev,
                                   struct device_attribute *da, char *buf)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);

        return sysfs_emit(buf, "%li\n", data->rshunt);
}

static ssize_t shunt_resistor_store(struct device *dev,
                                    struct device_attribute *da,
                                    const char *buf, size_t count)
{
        struct ina2xx_data *data = dev_get_drvdata(dev);
        unsigned long val;
        int status;

        status = kstrtoul(buf, 10, &val);
        if (status < 0)
                return status;

        hwmon_lock(dev);
        status = ina2xx_set_shunt(data, val);
        hwmon_unlock(dev);
        if (status < 0)
                return status;
        return count;
}

static DEVICE_ATTR_RW(shunt_resistor);

/* pointers to created device attributes */
static struct attribute *ina2xx_attrs[] = {
        &dev_attr_shunt_resistor.attr,
        NULL,
};
ATTRIBUTE_GROUPS(ina2xx);

/*
 * Initialize chip
 */
static int ina2xx_init(struct device *dev, struct ina2xx_data *data)
{
        struct regmap *regmap = data->regmap;
        u32 shunt;
        int ret;

        if (data->config->has_ishunt)
                shunt = INA260_RSHUNT;
        else if (device_property_read_u32(dev, "shunt-resistor", &shunt) < 0)
                shunt = INA2XX_RSHUNT_DEFAULT;

        ret = ina2xx_set_shunt(data, shunt);
        if (ret < 0)
                return ret;

        ret = regmap_write(regmap, INA2XX_CONFIG, data->config->config_default);
        if (ret < 0)
                return ret;

        if (data->config->has_alerts) {
                bool active_high = device_property_read_bool(dev, "ti,alert-polarity-active-high");

                regmap_update_bits(regmap, INA226_MASK_ENABLE,
                                   INA226_ALERT_LATCH_ENABLE | INA226_ALERT_POLARITY,
                                   INA226_ALERT_LATCH_ENABLE |
                                                FIELD_PREP(INA226_ALERT_POLARITY, active_high));
        }
        if (data->config->has_power_average) {
                if (data->chip == sy24655) {
                        /*
                         * Initialize the power accumulation method to continuous
                         * mode and clear the EIN register after each read of the
                         * EIN register
                         */
                        ret = regmap_write(regmap, SY24655_ACCUM_CONFIG,
                                           SY24655_ACCUM_CONFIG_DEFAULT);
                        if (ret < 0)
                                return ret;
                }
        }

        if (data->config->has_ishunt)
                return 0;

        /*
         * Calibration register is set to the best value, which eliminates
         * truncation errors on calculating current register in hardware.
         * According to datasheet (eq. 3) the best values are 2048 for
         * ina226 and 4096 for ina219. They are hardcoded as calibration_value.
         */
        return regmap_write(regmap, INA2XX_CALIBRATION,
                            data->config->calibration_value);
}

static int ina2xx_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct ina2xx_data *data;
        struct device *hwmon_dev;
        enum ina2xx_ids chip;
        int ret;

        chip = (uintptr_t)i2c_get_match_data(client);

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

        /* set the device type */
        data->client = client;
        data->config = &ina2xx_config[chip];
        data->chip = chip;

        data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
        if (IS_ERR(data->regmap)) {
                dev_err(dev, "failed to allocate register map\n");
                return PTR_ERR(data->regmap);
        }

        /*
         * Regulator core returns -ENODEV if the 'vs' is not available.
         * Hence the check for -ENODEV return code is necessary.
         */
        ret = devm_regulator_get_enable_optional(dev, "vs");
        if (ret < 0 && ret != -ENODEV)
                return dev_err_probe(dev, ret, "failed to enable vs regulator\n");

        ret = ina2xx_init(dev, data);
        if (ret < 0)
                return dev_err_probe(dev, ret, "failed to configure device\n");

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         data, &ina2xx_chip_info,
                                                         data->config->has_ishunt ?
                                                                NULL : ina2xx_groups);
        if (IS_ERR(hwmon_dev))
                return PTR_ERR(hwmon_dev);

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

        return 0;
}

static const struct i2c_device_id ina2xx_id[] = {
        { "ina219", ina219 },
        { "ina220", ina219 },
        { "ina226", ina226 },
        { "ina230", ina226 },
        { "ina231", ina226 },
        { "ina260", ina260 },
        { "sy24655", sy24655 },
        { }
};
MODULE_DEVICE_TABLE(i2c, ina2xx_id);

static const struct of_device_id __maybe_unused ina2xx_of_match[] = {
        {
                .compatible = "silergy,sy24655",
                .data = (void *)sy24655
        },
        {
                .compatible = "ti,ina219",
                .data = (void *)ina219
        },
        {
                .compatible = "ti,ina220",
                .data = (void *)ina219
        },
        {
                .compatible = "ti,ina226",
                .data = (void *)ina226
        },
        {
                .compatible = "ti,ina230",
                .data = (void *)ina226
        },
        {
                .compatible = "ti,ina231",
                .data = (void *)ina226
        },
        {
                .compatible = "ti,ina260",
                .data = (void *)ina260
        },
        { }
};
MODULE_DEVICE_TABLE(of, ina2xx_of_match);

static struct i2c_driver ina2xx_driver = {
        .driver = {
                .name   = "ina2xx",
                .of_match_table = of_match_ptr(ina2xx_of_match),
        },
        .probe          = ina2xx_probe,
        .id_table       = ina2xx_id,
};

module_i2c_driver(ina2xx_driver);

MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
MODULE_DESCRIPTION("ina2xx driver");
MODULE_LICENSE("GPL");