// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for Texas Instruments TMP512, TMP513 power monitor chips
 *
 * TMP513:
 * Thermal/Power Management with Triple Remote and
 * Local Temperature Sensor and Current Shunt Monitor
 * Datasheet: https://www.ti.com/lit/gpn/tmp513
 *
 * TMP512:
 * Thermal/Power Management with Dual Remote
 *      and Local Temperature Sensor and Current Shunt Monitor
 * Datasheet: https://www.ti.com/lit/gpn/tmp512
 *
 * Copyright (C) 2019 Eric Tremblay <etremblay@distech-controls.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 */

#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/math.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/units.h>

// Common register definition
#define TMP51X_SHUNT_CONFIG             0x00
#define TMP51X_TEMP_CONFIG              0x01
#define TMP51X_STATUS                   0x02
#define TMP51X_SMBUS_ALERT              0x03
#define TMP51X_SHUNT_CURRENT_RESULT     0x04
#define TMP51X_BUS_VOLTAGE_RESULT       0x05
#define TMP51X_POWER_RESULT             0x06
#define TMP51X_BUS_CURRENT_RESULT       0x07
#define TMP51X_LOCAL_TEMP_RESULT        0x08
#define TMP51X_REMOTE_TEMP_RESULT_1     0x09
#define TMP51X_REMOTE_TEMP_RESULT_2     0x0A
#define TMP51X_SHUNT_CURRENT_H_LIMIT    0x0C
#define TMP51X_SHUNT_CURRENT_L_LIMIT    0x0D
#define TMP51X_BUS_VOLTAGE_H_LIMIT      0x0E
#define TMP51X_BUS_VOLTAGE_L_LIMIT      0x0F
#define TMP51X_POWER_LIMIT              0x10
#define TMP51X_LOCAL_TEMP_LIMIT 0x11
#define TMP51X_REMOTE_TEMP_LIMIT_1      0x12
#define TMP51X_REMOTE_TEMP_LIMIT_2      0x13
#define TMP51X_SHUNT_CALIBRATION        0x15
#define TMP51X_N_FACTOR_AND_HYST_1      0x16
#define TMP51X_N_FACTOR_2               0x17
#define TMP51X_MAN_ID_REG               0xFE
#define TMP51X_DEVICE_ID_REG            0xFF

// TMP513 specific register definition
#define TMP513_REMOTE_TEMP_RESULT_3     0x0B
#define TMP513_REMOTE_TEMP_LIMIT_3      0x14
#define TMP513_N_FACTOR_3               0x18

// Common attrs, and NULL
#define TMP51X_MANUFACTURER_ID          0x55FF

#define TMP512_DEVICE_ID                0x22FF
#define TMP513_DEVICE_ID                0x23FF

// Default config
#define TMP51X_SHUNT_CONFIG_DEFAULT     0x399F
#define TMP51X_SHUNT_VALUE_DEFAULT      1000
#define TMP51X_VBUS_RANGE_DEFAULT       TMP51X_VBUS_RANGE_32V
#define TMP51X_PGA_DEFAULT              8
#define TMP51X_MAX_REGISTER_ADDR        0xFF

// Mask and shift
#define CURRENT_SENSE_VOLTAGE_320_MASK  0x1800
#define CURRENT_SENSE_VOLTAGE_160_MASK  0x1000
#define CURRENT_SENSE_VOLTAGE_80_MASK   0x0800
#define CURRENT_SENSE_VOLTAGE_40_MASK   0

#define TMP51X_BUS_VOLTAGE_MASK         0x2000
#define TMP51X_NFACTOR_MASK             0xFF00
#define TMP51X_HYST_MASK                0x00FF

#define TMP51X_BUS_VOLTAGE_SHIFT        3
#define TMP51X_TEMP_SHIFT               3

// Alarms
#define TMP51X_SHUNT_CURRENT_H_LIMIT_POS        15
#define TMP51X_SHUNT_CURRENT_L_LIMIT_POS        14
#define TMP51X_BUS_VOLTAGE_H_LIMIT_POS          13
#define TMP51X_BUS_VOLTAGE_L_LIMIT_POS          12
#define TMP51X_POWER_LIMIT_POS                  11
#define TMP51X_LOCAL_TEMP_LIMIT_POS             10
#define TMP51X_REMOTE_TEMP_LIMIT_1_POS          9
#define TMP51X_REMOTE_TEMP_LIMIT_2_POS          8
#define TMP513_REMOTE_TEMP_LIMIT_3_POS          7

#define TMP51X_VBUS_RANGE_32V           (32 * MICRO)
#define TMP51X_VBUS_RANGE_16V           (16 * MICRO)

// Max and Min value
#define MAX_BUS_VOLTAGE_32_LIMIT        32764
#define MAX_BUS_VOLTAGE_16_LIMIT        16382

// Max possible value is -256 to +256 but datasheet indicated -40 to 125.
#define MAX_TEMP_LIMIT                  125000
#define MIN_TEMP_LIMIT                  -40000

#define MAX_TEMP_HYST                   127500

#define TMP512_MAX_CHANNELS             3
#define TMP513_MAX_CHANNELS             4

#define TMP51X_TEMP_CONFIG_CONV_RATE    GENMASK(9, 7)
#define TMP51X_TEMP_CONFIG_RC           BIT(10)
#define TMP51X_TEMP_CHANNEL_MASK(n)     (GENMASK((n) - 1, 0) << 11)
#define TMP51X_TEMP_CONFIG_CONT         BIT(15)
#define TMP51X_TEMP_CONFIG_DEFAULT(n)                                   \
        (TMP51X_TEMP_CHANNEL_MASK(n) | TMP51X_TEMP_CONFIG_CONT |        \
         TMP51X_TEMP_CONFIG_CONV_RATE | TMP51X_TEMP_CONFIG_RC)

static const u8 TMP51X_TEMP_INPUT[4] = {
        TMP51X_LOCAL_TEMP_RESULT,
        TMP51X_REMOTE_TEMP_RESULT_1,
        TMP51X_REMOTE_TEMP_RESULT_2,
        TMP513_REMOTE_TEMP_RESULT_3
};

static const u8 TMP51X_TEMP_CRIT[4] = {
        TMP51X_LOCAL_TEMP_LIMIT,
        TMP51X_REMOTE_TEMP_LIMIT_1,
        TMP51X_REMOTE_TEMP_LIMIT_2,
        TMP513_REMOTE_TEMP_LIMIT_3
};

static const u8 TMP51X_TEMP_CRIT_ALARM[4] = {
        TMP51X_LOCAL_TEMP_LIMIT_POS,
        TMP51X_REMOTE_TEMP_LIMIT_1_POS,
        TMP51X_REMOTE_TEMP_LIMIT_2_POS,
        TMP513_REMOTE_TEMP_LIMIT_3_POS
};

static const u8 TMP51X_TEMP_CRIT_HYST[4] = {
        TMP51X_N_FACTOR_AND_HYST_1,
        TMP51X_N_FACTOR_AND_HYST_1,
        TMP51X_N_FACTOR_AND_HYST_1,
        TMP51X_N_FACTOR_AND_HYST_1
};

static const u8 TMP51X_CURR_INPUT[2] = {
        TMP51X_SHUNT_CURRENT_RESULT,
        TMP51X_BUS_CURRENT_RESULT
};

static const struct regmap_config tmp51x_regmap_config = {
        .reg_bits = 8,
        .val_bits = 16,
        .max_register = TMP51X_MAX_REGISTER_ADDR,
};

struct tmp51x_data {
        u16 shunt_config;
        u16 pga_gain;
        u32 vbus_range_uvolt;

        u16 temp_config;
        u32 nfactor[3];

        u32 shunt_uohms;

        u32 curr_lsb_ua;
        u32 pwr_lsb_uw;

        u8 max_channels;
        struct regmap *regmap;
};

// Set the shift based on the gain: 8 -> 1, 4 -> 2, 2 -> 3, 1 -> 4
static inline u8 tmp51x_get_pga_shift(struct tmp51x_data *data)
{
        return 5 - ffs(data->pga_gain);
}

static int tmp51x_get_value(struct tmp51x_data *data, u8 reg, u8 pos,
                            unsigned int regval, long *val)
{
        switch (reg) {
        case TMP51X_STATUS:
                *val = (regval >> pos) & 1;
                break;
        case TMP51X_SHUNT_CURRENT_RESULT:
        case TMP51X_SHUNT_CURRENT_H_LIMIT:
        case TMP51X_SHUNT_CURRENT_L_LIMIT:
                /*
                 * The valus is read in voltage in the chip but reported as
                 * current to the user.
                 * 2's complement number shifted by one to four depending
                 * on the pga gain setting. 1lsb = 10uV
                 */
                *val = sign_extend32(regval,
                                     reg == TMP51X_SHUNT_CURRENT_RESULT ?
                                     16 - tmp51x_get_pga_shift(data) : 15);
                *val = DIV_ROUND_CLOSEST(*val * 10 * (long)MILLI, (long)data->shunt_uohms);

                break;
        case TMP51X_BUS_VOLTAGE_RESULT:
        case TMP51X_BUS_VOLTAGE_H_LIMIT:
        case TMP51X_BUS_VOLTAGE_L_LIMIT:
                // 1lsb = 4mV
                *val = (regval >> TMP51X_BUS_VOLTAGE_SHIFT) * 4;
                break;
        case TMP51X_POWER_RESULT:
        case TMP51X_POWER_LIMIT:
                // Power = (current * BusVoltage) / 5000
                *val = regval * data->pwr_lsb_uw;
                break;
        case TMP51X_BUS_CURRENT_RESULT:
                // Current = (ShuntVoltage * CalibrationRegister) / 4096
                *val = sign_extend32(regval, 15) * (long)data->curr_lsb_ua;
                *val = DIV_ROUND_CLOSEST(*val, (long)MILLI);
                break;
        case TMP51X_LOCAL_TEMP_RESULT:
        case TMP51X_REMOTE_TEMP_RESULT_1:
        case TMP51X_REMOTE_TEMP_RESULT_2:
        case TMP513_REMOTE_TEMP_RESULT_3:
        case TMP51X_LOCAL_TEMP_LIMIT:
        case TMP51X_REMOTE_TEMP_LIMIT_1:
        case TMP51X_REMOTE_TEMP_LIMIT_2:
        case TMP513_REMOTE_TEMP_LIMIT_3:
                // 1lsb = 0.0625 degrees centigrade
                *val = sign_extend32(regval, 15) >> TMP51X_TEMP_SHIFT;
                *val = DIV_ROUND_CLOSEST(*val * 625, 10);
                break;
        case TMP51X_N_FACTOR_AND_HYST_1:
                // 1lsb = 0.5 degrees centigrade
                *val = (regval & TMP51X_HYST_MASK) * 500;
                break;
        default:
                // Programmer goofed
                WARN_ON_ONCE(1);
                *val = 0;
                return -EOPNOTSUPP;
        }

        return 0;
}

static int tmp51x_set_value(struct tmp51x_data *data, u8 reg, long val)
{
        int regval, max_val;
        u32 mask = 0;

        switch (reg) {
        case TMP51X_SHUNT_CURRENT_H_LIMIT:
        case TMP51X_SHUNT_CURRENT_L_LIMIT:
                /*
                 * The user enter current value and we convert it to
                 * voltage. 1lsb = 10uV
                 */
                val = DIV_ROUND_CLOSEST(val * (long)data->shunt_uohms, 10 * (long)MILLI);
                max_val = U16_MAX >> tmp51x_get_pga_shift(data);
                regval = clamp_val(val, -max_val, max_val);
                break;
        case TMP51X_BUS_VOLTAGE_H_LIMIT:
        case TMP51X_BUS_VOLTAGE_L_LIMIT:
                // 1lsb = 4mV
                max_val = (data->vbus_range_uvolt == TMP51X_VBUS_RANGE_32V) ?
                        MAX_BUS_VOLTAGE_32_LIMIT : MAX_BUS_VOLTAGE_16_LIMIT;

                val = clamp_val(DIV_ROUND_CLOSEST(val, 4), 0, max_val);
                regval = val << TMP51X_BUS_VOLTAGE_SHIFT;
                break;
        case TMP51X_POWER_LIMIT:
                regval = clamp_val(DIV_ROUND_CLOSEST(val, data->pwr_lsb_uw), 0,
                                   U16_MAX);
                break;
        case TMP51X_LOCAL_TEMP_LIMIT:
        case TMP51X_REMOTE_TEMP_LIMIT_1:
        case TMP51X_REMOTE_TEMP_LIMIT_2:
        case TMP513_REMOTE_TEMP_LIMIT_3:
                // 1lsb = 0.0625 degrees centigrade
                val = clamp_val(val, MIN_TEMP_LIMIT, MAX_TEMP_LIMIT);
                regval = DIV_ROUND_CLOSEST(val * 10, 625) << TMP51X_TEMP_SHIFT;
                break;
        case TMP51X_N_FACTOR_AND_HYST_1:
                // 1lsb = 0.5 degrees centigrade
                val = clamp_val(val, 0, MAX_TEMP_HYST);
                regval = DIV_ROUND_CLOSEST(val, 500);
                mask = TMP51X_HYST_MASK;
                break;
        default:
                // Programmer goofed
                WARN_ON_ONCE(1);
                return -EOPNOTSUPP;
        }

        if (mask == 0)
                return regmap_write(data->regmap, reg, regval);
        else
                return regmap_update_bits(data->regmap, reg, mask, regval);
}

static u8 tmp51x_get_reg(enum hwmon_sensor_types type, u32 attr, int channel)
{
        switch (type) {
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        return TMP51X_TEMP_INPUT[channel];
                case hwmon_temp_crit_alarm:
                        return TMP51X_STATUS;
                case hwmon_temp_crit:
                        return TMP51X_TEMP_CRIT[channel];
                case hwmon_temp_crit_hyst:
                        return TMP51X_TEMP_CRIT_HYST[channel];
                }
                break;
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                        return TMP51X_BUS_VOLTAGE_RESULT;
                case hwmon_in_lcrit_alarm:
                case hwmon_in_crit_alarm:
                        return TMP51X_STATUS;
                case hwmon_in_lcrit:
                        return TMP51X_BUS_VOLTAGE_L_LIMIT;
                case hwmon_in_crit:
                        return TMP51X_BUS_VOLTAGE_H_LIMIT;
                }
                break;
        case hwmon_curr:
                switch (attr) {
                case hwmon_curr_input:
                        return TMP51X_CURR_INPUT[channel];
                case hwmon_curr_lcrit_alarm:
                case hwmon_curr_crit_alarm:
                        return TMP51X_STATUS;
                case hwmon_curr_lcrit:
                        return TMP51X_SHUNT_CURRENT_L_LIMIT;
                case hwmon_curr_crit:
                        return TMP51X_SHUNT_CURRENT_H_LIMIT;
                }
                break;
        case hwmon_power:
                switch (attr) {
                case hwmon_power_input:
                        return TMP51X_POWER_RESULT;
                case hwmon_power_crit_alarm:
                        return TMP51X_STATUS;
                case hwmon_power_crit:
                        return TMP51X_POWER_LIMIT;
                }
                break;
        default:
                break;
        }

        return 0;
}

static u8 tmp51x_get_status_pos(enum hwmon_sensor_types type, u32 attr,
                                int channel)
{
        switch (type) {
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_crit_alarm:
                        return TMP51X_TEMP_CRIT_ALARM[channel];
                }
                break;
        case hwmon_in:
                switch (attr) {
                case hwmon_in_lcrit_alarm:
                        return TMP51X_BUS_VOLTAGE_L_LIMIT_POS;
                case hwmon_in_crit_alarm:
                        return TMP51X_BUS_VOLTAGE_H_LIMIT_POS;
                }
                break;
        case hwmon_curr:
                switch (attr) {
                case hwmon_curr_lcrit_alarm:
                        return TMP51X_SHUNT_CURRENT_L_LIMIT_POS;
                case hwmon_curr_crit_alarm:
                        return TMP51X_SHUNT_CURRENT_H_LIMIT_POS;
                }
                break;
        case hwmon_power:
                switch (attr) {
                case hwmon_power_crit_alarm:
                        return TMP51X_POWER_LIMIT_POS;
                }
                break;
        default:
                break;
        }

        return 0;
}

static int tmp51x_read(struct device *dev, enum hwmon_sensor_types type,
                       u32 attr, int channel, long *val)
{
        struct tmp51x_data *data = dev_get_drvdata(dev);
        int ret;
        u32 regval;
        u8 pos = 0, reg = 0;

        reg = tmp51x_get_reg(type, attr, channel);
        if (reg == 0)
                return -EOPNOTSUPP;

        if (reg == TMP51X_STATUS)
                pos = tmp51x_get_status_pos(type, attr, channel);

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

        return tmp51x_get_value(data, reg, pos, regval, val);
}

static int tmp51x_write(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long val)
{
        u8 reg = 0;

        reg = tmp51x_get_reg(type, attr, channel);
        if (reg == 0)
                return -EOPNOTSUPP;

        return tmp51x_set_value(dev_get_drvdata(dev), reg, val);
}

static umode_t tmp51x_is_visible(const void *_data,
                                 enum hwmon_sensor_types type, u32 attr,
                                 int channel)
{
        const struct tmp51x_data *data = _data;

        switch (type) {
        case hwmon_temp:
                if (channel >= data->max_channels)
                        return 0;
                switch (attr) {
                case hwmon_temp_input:
                case hwmon_temp_crit_alarm:
                        return 0444;
                case hwmon_temp_crit:
                        return 0644;
                case hwmon_temp_crit_hyst:
                        if (channel == 0)
                                return 0644;
                        return 0444;
                }
                break;
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                case hwmon_in_lcrit_alarm:
                case hwmon_in_crit_alarm:
                        return 0444;
                case hwmon_in_lcrit:
                case hwmon_in_crit:
                        return 0644;
                }
                break;
        case hwmon_curr:
                if (!data->shunt_uohms)
                        return 0;

                switch (attr) {
                case hwmon_curr_input:
                case hwmon_curr_lcrit_alarm:
                case hwmon_curr_crit_alarm:
                        return 0444;
                case hwmon_curr_lcrit:
                case hwmon_curr_crit:
                        return 0644;
                }
                break;
        case hwmon_power:
                if (!data->shunt_uohms)
                        return 0;

                switch (attr) {
                case hwmon_power_input:
                case hwmon_power_crit_alarm:
                        return 0444;
                case hwmon_power_crit:
                        return 0644;
                }
                break;
        default:
                break;
        }
        return 0;
}

static const struct hwmon_channel_info * const tmp51x_info[] = {
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
                           HWMON_T_CRIT_HYST,
                           HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
                           HWMON_T_CRIT_HYST,
                           HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
                           HWMON_T_CRIT_HYST,
                           HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
                           HWMON_T_CRIT_HYST),
        HWMON_CHANNEL_INFO(in,
                           HWMON_I_INPUT | HWMON_I_LCRIT | HWMON_I_LCRIT_ALARM |
                           HWMON_I_CRIT | HWMON_I_CRIT_ALARM),
        HWMON_CHANNEL_INFO(curr,
                           HWMON_C_INPUT | HWMON_C_LCRIT | HWMON_C_LCRIT_ALARM |
                           HWMON_C_CRIT | HWMON_C_CRIT_ALARM,
                           HWMON_C_INPUT),
        HWMON_CHANNEL_INFO(power,
                           HWMON_P_INPUT | HWMON_P_CRIT | HWMON_P_CRIT_ALARM),
        NULL
};

static const struct hwmon_ops tmp51x_hwmon_ops = {
        .is_visible = tmp51x_is_visible,
        .read = tmp51x_read,
        .write = tmp51x_write,
};

static const struct hwmon_chip_info tmp51x_chip_info = {
        .ops = &tmp51x_hwmon_ops,
        .info = tmp51x_info,
};

/*
 * Calibrate the tmp51x following the datasheet method
 */
static int tmp51x_calibrate(struct tmp51x_data *data)
{
        int vshunt_max = data->pga_gain * 40;
        u64 max_curr_ma;
        u32 div;

        /*
         * If shunt_uohms is equal to 0, the calibration should be set to 0.
         * The consequence will be that the current and power measurement engine
         * of the sensor will not work. Temperature and voltage sensing will
         * continue to work.
         */
        if (data->shunt_uohms == 0)
                return regmap_write(data->regmap, TMP51X_SHUNT_CALIBRATION, 0);

        max_curr_ma = DIV_ROUND_CLOSEST_ULL(vshunt_max * MICRO, data->shunt_uohms);

        /*
         * Calculate the minimal bit resolution for the current and the power.
         * Those values will be used during register interpretation.
         */
        data->curr_lsb_ua = DIV_ROUND_CLOSEST_ULL(max_curr_ma * MILLI, 32767);
        data->pwr_lsb_uw = 20 * data->curr_lsb_ua;

        div = DIV_ROUND_CLOSEST_ULL(data->curr_lsb_ua * data->shunt_uohms, MICRO);

        return regmap_write(data->regmap, TMP51X_SHUNT_CALIBRATION,
                            DIV_ROUND_CLOSEST(40960, div));
}

/*
 * Initialize the configuration and calibration registers.
 */
static int tmp51x_init(struct tmp51x_data *data)
{
        unsigned int regval;
        int ret = regmap_write(data->regmap, TMP51X_SHUNT_CONFIG,
                               data->shunt_config);
        if (ret < 0)
                return ret;

        ret = regmap_write(data->regmap, TMP51X_TEMP_CONFIG, data->temp_config);
        if (ret < 0)
                return ret;

        // nFactor configuration
        ret = regmap_update_bits(data->regmap, TMP51X_N_FACTOR_AND_HYST_1,
                                 TMP51X_NFACTOR_MASK, data->nfactor[0] << 8);
        if (ret < 0)
                return ret;

        ret = regmap_write(data->regmap, TMP51X_N_FACTOR_2,
                           data->nfactor[1] << 8);
        if (ret < 0)
                return ret;

        if (data->max_channels == TMP513_MAX_CHANNELS) {
                ret = regmap_write(data->regmap, TMP513_N_FACTOR_3,
                                   data->nfactor[2] << 8);
                if (ret < 0)
                        return ret;
        }

        ret = tmp51x_calibrate(data);
        if (ret < 0)
                return ret;

        // Read the status register before using as the datasheet propose
        return regmap_read(data->regmap, TMP51X_STATUS, &regval);
}

static const struct i2c_device_id tmp51x_id[] = {
        { "tmp512", TMP512_MAX_CHANNELS },
        { "tmp513", TMP513_MAX_CHANNELS },
        { }
};
MODULE_DEVICE_TABLE(i2c, tmp51x_id);

static const struct of_device_id tmp51x_of_match[] = {
        { .compatible = "ti,tmp512", .data = (void *)TMP512_MAX_CHANNELS },
        { .compatible = "ti,tmp513", .data = (void *)TMP513_MAX_CHANNELS },
        { }
};
MODULE_DEVICE_TABLE(of, tmp51x_of_match);

static int tmp51x_vbus_range_to_reg(struct device *dev,
                                    struct tmp51x_data *data)
{
        if (data->vbus_range_uvolt == TMP51X_VBUS_RANGE_32V) {
                data->shunt_config |= TMP51X_BUS_VOLTAGE_MASK;
        } else if (data->vbus_range_uvolt == TMP51X_VBUS_RANGE_16V) {
                data->shunt_config &= ~TMP51X_BUS_VOLTAGE_MASK;
        } else {
                return dev_err_probe(dev, -EINVAL,
                                     "ti,bus-range-microvolt is invalid: %u\n",
                                     data->vbus_range_uvolt);
        }
        return 0;
}

static int tmp51x_pga_gain_to_reg(struct device *dev, struct tmp51x_data *data)
{
        if (data->pga_gain == 8) {
                data->shunt_config |= CURRENT_SENSE_VOLTAGE_320_MASK;
        } else if (data->pga_gain == 4) {
                data->shunt_config |= CURRENT_SENSE_VOLTAGE_160_MASK;
        } else if (data->pga_gain == 2) {
                data->shunt_config |= CURRENT_SENSE_VOLTAGE_80_MASK;
        } else if (data->pga_gain == 1) {
                data->shunt_config |= CURRENT_SENSE_VOLTAGE_40_MASK;
        } else {
                return dev_err_probe(dev, -EINVAL,
                                     "ti,pga-gain is invalid: %u\n", data->pga_gain);
        }
        return 0;
}

static int tmp51x_read_properties(struct device *dev, struct tmp51x_data *data)
{
        int ret;
        u32 val;

        ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", &val);
        data->shunt_uohms = (ret >= 0) ? val : TMP51X_SHUNT_VALUE_DEFAULT;

        ret = device_property_read_u32(dev, "ti,bus-range-microvolt", &val);
        data->vbus_range_uvolt = (ret >= 0) ? val : TMP51X_VBUS_RANGE_DEFAULT;
        ret = tmp51x_vbus_range_to_reg(dev, data);
        if (ret < 0)
                return ret;

        ret = device_property_read_u32(dev, "ti,pga-gain", &val);
        data->pga_gain = (ret >= 0) ? val : TMP51X_PGA_DEFAULT;
        ret = tmp51x_pga_gain_to_reg(dev, data);
        if (ret < 0)
                return ret;

        device_property_read_u32_array(dev, "ti,nfactor", data->nfactor,
                                       data->max_channels - 1);

        // Check if shunt value is compatible with pga-gain
        if (data->shunt_uohms > data->pga_gain * 40 * MICRO) {
                return dev_err_probe(dev, -EINVAL,
                                     "shunt-resistor: %u too big for pga_gain: %u\n",
                                     data->shunt_uohms, data->pga_gain);
        }

        return 0;
}

static void tmp51x_use_default(struct tmp51x_data *data)
{
        data->vbus_range_uvolt = TMP51X_VBUS_RANGE_DEFAULT;
        data->pga_gain = TMP51X_PGA_DEFAULT;
        data->shunt_uohms = TMP51X_SHUNT_VALUE_DEFAULT;
}

static int tmp51x_configure(struct device *dev, struct tmp51x_data *data)
{
        data->shunt_config = TMP51X_SHUNT_CONFIG_DEFAULT;
        data->temp_config = TMP51X_TEMP_CONFIG_DEFAULT(data->max_channels);

        if (dev->of_node)
                return tmp51x_read_properties(dev, data);

        tmp51x_use_default(data);

        return 0;
}

static int tmp51x_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct tmp51x_data *data;
        struct device *hwmon_dev;
        int ret;

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

        data->max_channels = (uintptr_t)i2c_get_match_data(client);

        ret = tmp51x_configure(dev, data);
        if (ret < 0)
                return dev_err_probe(dev, ret, "error configuring the device\n");

        data->regmap = devm_regmap_init_i2c(client, &tmp51x_regmap_config);
        if (IS_ERR(data->regmap))
                return dev_err_probe(dev, PTR_ERR(data->regmap),
                                     "failed to allocate register map\n");

        ret = tmp51x_init(data);
        if (ret < 0)
                return dev_err_probe(dev, ret, "error configuring the device\n");

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         data,
                                                         &tmp51x_chip_info,
                                                         NULL);
        if (IS_ERR(hwmon_dev))
                return PTR_ERR(hwmon_dev);

        dev_dbg(dev, "power monitor %s\n", client->name);

        return 0;
}

static struct i2c_driver tmp51x_driver = {
        .driver = {
                .name   = "tmp51x",
                .of_match_table = tmp51x_of_match,
        },
        .probe          = tmp51x_probe,
        .id_table       = tmp51x_id,
};

module_i2c_driver(tmp51x_driver);

MODULE_AUTHOR("Eric Tremblay <etremblay@distechcontrols.com>");
MODULE_DESCRIPTION("tmp51x driver");
MODULE_LICENSE("GPL");