// SPDX-License-Identifier: GPL-2.0+
/*
 * Fuel gauge driver for Maxim 17201/17205
 *
 * based on max1721x_battery.c
 *
 * Copyright (C) 2024 Liebherr-Electronics and Drives GmbH
 */

#include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>

#include <linux/unaligned.h>

/* SBS compliant registers */
#define MAX172XX_TEMP1                  0x34
#define MAX172XX_INT_TEMP               0x35
#define MAX172XX_TEMP2                  0x3B

/* Nonvolatile registers */
#define MAX1720X_NXTABLE0               0x80
#define MAX1720X_NRSENSE                0xCF    /* RSense in 10^-5 Ohm */
#define MAX1720X_NDEVICE_NAME4          0xDF

/* ModelGauge m5 */
#define MAX172XX_STATUS                 0x00    /* Status */
#define MAX172XX_STATUS_BAT_ABSENT      BIT(3)  /* Battery absent */
#define MAX172XX_STATUS_IMX             BIT(6)  /* Maximum Current Alert Threshold Exceeded */
#define MAX172XX_STATUS_VMN             BIT(8)  /* Minimum Voltage Alert Threshold Exceeded */
#define MAX172XX_STATUS_TMN             BIT(9)  /* Minimum Temperature Alert Threshold Exceeded */
#define MAX172XX_STATUS_VMX             BIT(12) /* Maximum Voltage Alert Threshold Exceeded */
#define MAX172XX_STATUS_TMX             BIT(13) /* Maximum Temperature Alert Threshold Exceeded */
#define MAX172XX_REPCAP                 0x05    /* Average capacity */
#define MAX172XX_REPSOC                 0x06    /* Percentage of charge */
#define MAX172XX_TEMP                   0x08    /* Temperature */
#define MAX172XX_CURRENT                0x0A    /* Actual current */
#define MAX172XX_AVG_CURRENT            0x0B    /* Average current */
#define MAX172XX_FULL_CAP               0x10    /* Calculated full capacity */
#define MAX172XX_TTE                    0x11    /* Time to empty */
#define MAX172XX_AVG_TA                 0x16    /* Average temperature */
#define MAX172XX_CYCLES                 0x17
#define MAX172XX_DESIGN_CAP             0x18    /* Design capacity */
#define MAX172XX_AVG_VCELL              0x19
#define MAX172XX_TTF                    0x20    /* Time to full */
#define MAX172XX_DEV_NAME               0x21    /* Device name */
#define MAX172XX_DEV_NAME_TYPE_MASK     GENMASK(3, 0)
#define MAX172XX_DEV_NAME_TYPE_MAX17201 BIT(0)
#define MAX172XX_DEV_NAME_TYPE_MAX17205 (BIT(0) | BIT(2))
#define MAX172XX_QR_TABLE10             0x22
#define MAX172XX_BATT                   0xDA    /* Battery voltage */
#define MAX172XX_ATAVCAP                0xDF

static const char *const max1720x_manufacturer = "Maxim Integrated";
static const char *const max17201_model = "MAX17201";
static const char *const max17205_model = "MAX17205";

struct max1720x_device_info {
        struct regmap *regmap;
        struct regmap *regmap_nv;
        struct i2c_client *ancillary;
        int rsense;
};

/*
 * Model Gauge M5 Algorithm output register
 * Volatile data (must not be cached)
 */
static const struct regmap_range max1720x_volatile_allow[] = {
        regmap_reg_range(MAX172XX_STATUS, MAX172XX_CYCLES),
        regmap_reg_range(MAX172XX_AVG_VCELL, MAX172XX_TTF),
        regmap_reg_range(MAX172XX_QR_TABLE10, MAX172XX_ATAVCAP),
};

static const struct regmap_range max1720x_readable_allow[] = {
        regmap_reg_range(MAX172XX_STATUS, MAX172XX_ATAVCAP),
};

static const struct regmap_range max1720x_readable_deny[] = {
        /* unused registers */
        regmap_reg_range(0x24, 0x26),
        regmap_reg_range(0x30, 0x31),
        regmap_reg_range(0x33, 0x34),
        regmap_reg_range(0x37, 0x37),
        regmap_reg_range(0x3B, 0x3C),
        regmap_reg_range(0x40, 0x41),
        regmap_reg_range(0x43, 0x44),
        regmap_reg_range(0x47, 0x49),
        regmap_reg_range(0x4B, 0x4C),
        regmap_reg_range(0x4E, 0xAF),
        regmap_reg_range(0xB1, 0xB3),
        regmap_reg_range(0xB5, 0xB7),
        regmap_reg_range(0xBF, 0xD0),
        regmap_reg_range(0xDB, 0xDB),
        regmap_reg_range(0xE0, 0xFF),
};

static const struct regmap_access_table max1720x_readable_regs = {
        .yes_ranges     = max1720x_readable_allow,
        .n_yes_ranges   = ARRAY_SIZE(max1720x_readable_allow),
        .no_ranges      = max1720x_readable_deny,
        .n_no_ranges    = ARRAY_SIZE(max1720x_readable_deny),
};

static const struct regmap_access_table max1720x_volatile_regs = {
        .yes_ranges     = max1720x_volatile_allow,
        .n_yes_ranges   = ARRAY_SIZE(max1720x_volatile_allow),
        .no_ranges      = max1720x_readable_deny,
        .n_no_ranges    = ARRAY_SIZE(max1720x_readable_deny),
};

static const struct regmap_config max1720x_regmap_cfg = {
        .reg_bits = 8,
        .val_bits = 16,
        .max_register = MAX172XX_ATAVCAP,
        .val_format_endian = REGMAP_ENDIAN_LITTLE,
        .rd_table = &max1720x_readable_regs,
        .volatile_table = &max1720x_volatile_regs,
        .cache_type = REGCACHE_MAPLE,
};

static const struct regmap_range max1720x_nvmem_allow[] = {
        regmap_reg_range(MAX172XX_TEMP1, MAX172XX_INT_TEMP),
        regmap_reg_range(MAX172XX_TEMP2, MAX172XX_TEMP2),
        regmap_reg_range(MAX1720X_NXTABLE0, MAX1720X_NDEVICE_NAME4),
};

static const struct regmap_range max1720x_nvmem_deny[] = {
        regmap_reg_range(0x00, 0x33),
        regmap_reg_range(0x36, 0x3A),
        regmap_reg_range(0x3C, 0x7F),
        regmap_reg_range(0xE0, 0xFF),
};

static const struct regmap_access_table max1720x_nvmem_regs = {
        .yes_ranges     = max1720x_nvmem_allow,
        .n_yes_ranges   = ARRAY_SIZE(max1720x_nvmem_allow),
        .no_ranges      = max1720x_nvmem_deny,
        .n_no_ranges    = ARRAY_SIZE(max1720x_nvmem_deny),
};

static const struct regmap_config max1720x_nvmem_regmap_cfg = {
        .reg_bits = 8,
        .val_bits = 16,
        .max_register = MAX1720X_NDEVICE_NAME4,
        .val_format_endian = REGMAP_ENDIAN_LITTLE,
        .rd_table = &max1720x_nvmem_regs,
};

static const struct nvmem_cell_info max1720x_nvmem_cells[] = {
        { .name = "nXTable0",  .offset = 0,  .bytes = 2, },
        { .name = "nXTable1",  .offset = 2,  .bytes = 2, },
        { .name = "nXTable2",  .offset = 4,  .bytes = 2, },
        { .name = "nXTable3",  .offset = 6,  .bytes = 2, },
        { .name = "nXTable4",  .offset = 8,  .bytes = 2, },
        { .name = "nXTable5",  .offset = 10, .bytes = 2, },
        { .name = "nXTable6",  .offset = 12, .bytes = 2, },
        { .name = "nXTable7",  .offset = 14, .bytes = 2, },
        { .name = "nXTable8",  .offset = 16, .bytes = 2, },
        { .name = "nXTable9",  .offset = 18, .bytes = 2, },
        { .name = "nXTable10", .offset = 20, .bytes = 2, },
        { .name = "nXTable11", .offset = 22, .bytes = 2, },
        { .name = "nUser18C",  .offset = 24, .bytes = 2, },
        { .name = "nUser18D",  .offset = 26, .bytes = 2, },
        { .name = "nODSCTh",   .offset = 28, .bytes = 2, },
        { .name = "nODSCCfg",  .offset = 30, .bytes = 2, },

        { .name = "nOCVTable0",  .offset = 32, .bytes = 2, },
        { .name = "nOCVTable1",  .offset = 34, .bytes = 2, },
        { .name = "nOCVTable2",  .offset = 36, .bytes = 2, },
        { .name = "nOCVTable3",  .offset = 38, .bytes = 2, },
        { .name = "nOCVTable4",  .offset = 40, .bytes = 2, },
        { .name = "nOCVTable5",  .offset = 42, .bytes = 2, },
        { .name = "nOCVTable6",  .offset = 44, .bytes = 2, },
        { .name = "nOCVTable7",  .offset = 46, .bytes = 2, },
        { .name = "nOCVTable8",  .offset = 48, .bytes = 2, },
        { .name = "nOCVTable9",  .offset = 50, .bytes = 2, },
        { .name = "nOCVTable10", .offset = 52, .bytes = 2, },
        { .name = "nOCVTable11", .offset = 54, .bytes = 2, },
        { .name = "nIChgTerm",   .offset = 56, .bytes = 2, },
        { .name = "nFilterCfg",  .offset = 58, .bytes = 2, },
        { .name = "nVEmpty",     .offset = 60, .bytes = 2, },
        { .name = "nLearnCfg",   .offset = 62, .bytes = 2, },

        { .name = "nQRTable00",  .offset = 64, .bytes = 2, },
        { .name = "nQRTable10",  .offset = 66, .bytes = 2, },
        { .name = "nQRTable20",  .offset = 68, .bytes = 2, },
        { .name = "nQRTable30",  .offset = 70, .bytes = 2, },
        { .name = "nCycles",     .offset = 72, .bytes = 2, },
        { .name = "nFullCapNom", .offset = 74, .bytes = 2, },
        { .name = "nRComp0",     .offset = 76, .bytes = 2, },
        { .name = "nTempCo",     .offset = 78, .bytes = 2, },
        { .name = "nIAvgEmpty",  .offset = 80, .bytes = 2, },
        { .name = "nFullCapRep", .offset = 82, .bytes = 2, },
        { .name = "nVoltTemp",   .offset = 84, .bytes = 2, },
        { .name = "nMaxMinCurr", .offset = 86, .bytes = 2, },
        { .name = "nMaxMinVolt", .offset = 88, .bytes = 2, },
        { .name = "nMaxMinTemp", .offset = 90, .bytes = 2, },
        { .name = "nSOC",        .offset = 92, .bytes = 2, },
        { .name = "nTimerH",     .offset = 94, .bytes = 2, },

        { .name = "nConfig",    .offset = 96,  .bytes = 2, },
        { .name = "nRippleCfg", .offset = 98,  .bytes = 2, },
        { .name = "nMiscCfg",   .offset = 100, .bytes = 2, },
        { .name = "nDesignCap", .offset = 102, .bytes = 2, },
        { .name = "nHibCfg",    .offset = 104, .bytes = 2, },
        { .name = "nPackCfg",   .offset = 106, .bytes = 2, },
        { .name = "nRelaxCfg",  .offset = 108, .bytes = 2, },
        { .name = "nConvgCfg",  .offset = 110, .bytes = 2, },
        { .name = "nNVCfg0",    .offset = 112, .bytes = 2, },
        { .name = "nNVCfg1",    .offset = 114, .bytes = 2, },
        { .name = "nNVCfg2",    .offset = 116, .bytes = 2, },
        { .name = "nSBSCfg",    .offset = 118, .bytes = 2, },
        { .name = "nROMID0",    .offset = 120, .bytes = 2, },
        { .name = "nROMID1",    .offset = 122, .bytes = 2, },
        { .name = "nROMID2",    .offset = 124, .bytes = 2, },
        { .name = "nROMID3",    .offset = 126, .bytes = 2, },

        { .name = "nVAlrtTh",      .offset = 128, .bytes = 2, },
        { .name = "nTAlrtTh",      .offset = 130, .bytes = 2, },
        { .name = "nSAlrtTh",      .offset = 132, .bytes = 2, },
        { .name = "nIAlrtTh",      .offset = 134, .bytes = 2, },
        { .name = "nUser1C4",      .offset = 136, .bytes = 2, },
        { .name = "nUser1C5",      .offset = 138, .bytes = 2, },
        { .name = "nFullSOCThr",   .offset = 140, .bytes = 2, },
        { .name = "nTTFCfg",       .offset = 142, .bytes = 2, },
        { .name = "nCGain",        .offset = 144, .bytes = 2, },
        { .name = "nTCurve",       .offset = 146, .bytes = 2, },
        { .name = "nTGain",        .offset = 148, .bytes = 2, },
        { .name = "nTOff",         .offset = 150, .bytes = 2, },
        { .name = "nManfctrName0", .offset = 152, .bytes = 2, },
        { .name = "nManfctrName1", .offset = 154, .bytes = 2, },
        { .name = "nManfctrName2", .offset = 156, .bytes = 2, },
        { .name = "nRSense",       .offset = 158, .bytes = 2, },

        { .name = "nUser1D0",       .offset = 160, .bytes = 2, },
        { .name = "nUser1D1",       .offset = 162, .bytes = 2, },
        { .name = "nAgeFcCfg",      .offset = 164, .bytes = 2, },
        { .name = "nDesignVoltage", .offset = 166, .bytes = 2, },
        { .name = "nUser1D4",       .offset = 168, .bytes = 2, },
        { .name = "nRFastVShdn",    .offset = 170, .bytes = 2, },
        { .name = "nManfctrDate",   .offset = 172, .bytes = 2, },
        { .name = "nFirstUsed",     .offset = 174, .bytes = 2, },
        { .name = "nSerialNumber0", .offset = 176, .bytes = 2, },
        { .name = "nSerialNumber1", .offset = 178, .bytes = 2, },
        { .name = "nSerialNumber2", .offset = 180, .bytes = 2, },
        { .name = "nDeviceName0",   .offset = 182, .bytes = 2, },
        { .name = "nDeviceName1",   .offset = 184, .bytes = 2, },
        { .name = "nDeviceName2",   .offset = 186, .bytes = 2, },
        { .name = "nDeviceName3",   .offset = 188, .bytes = 2, },
        { .name = "nDeviceName4",   .offset = 190, .bytes = 2, },
};

static const enum power_supply_property max1720x_battery_props[] = {
        POWER_SUPPLY_PROP_HEALTH,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
        POWER_SUPPLY_PROP_CHARGE_AVG,
        POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
        POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
        POWER_SUPPLY_PROP_TEMP,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CURRENT_AVG,
        POWER_SUPPLY_PROP_CHARGE_FULL,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
};

/* Convert regs value to power_supply units */

static int max172xx_time_to_ps(unsigned int reg)
{
        return reg * 5625 / 1000;       /* in sec. */
}

static int max172xx_percent_to_ps(unsigned int reg)
{
        return reg / 256;       /* in percent from 0 to 100 */
}

static int max172xx_voltage_to_ps(unsigned int reg)
{
        return reg * 1250;      /* in uV */
}

static int max172xx_capacity_to_ps(unsigned int reg,
                                   struct max1720x_device_info *info)
{
        return reg * (500000 / info->rsense);   /* in uAh */
}

/*
 * Current and temperature is signed values, so unsigned regs
 * value must be converted to signed type
 */

static int max172xx_temperature_to_ps(unsigned int reg)
{
        int val = (int16_t)reg;

        return val * 10 / 256; /* in tenths of deg. C */
}

/*
 * Calculating current registers resolution:
 *
 * RSense stored in 10^-5 Ohm, so measurement voltage must be
 * in 10^-11 Volts for get current in uA.
 * 16 bit current reg fullscale +/-51.2mV is 102400 uV.
 * So: 102400 / 65535 * 10^5 = 156252
 */
static int max172xx_current_to_voltage(unsigned int reg)
{
        int val = (int16_t)reg;

        return val * 156252;
}

static int max172xx_battery_health(struct max1720x_device_info *info,
                                   unsigned int *health)
{
        unsigned int status;
        int ret;

        ret = regmap_read(info->regmap, MAX172XX_STATUS, &status);
        if (ret < 0)
                return ret;

        if (status & MAX172XX_STATUS_VMN)
                *health = POWER_SUPPLY_HEALTH_DEAD;
        else if (status & MAX172XX_STATUS_VMX)
                *health = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
        else if (status & MAX172XX_STATUS_TMN)
                *health = POWER_SUPPLY_HEALTH_COLD;
        else if (status & MAX172XX_STATUS_TMX)
                *health = POWER_SUPPLY_HEALTH_OVERHEAT;
        else if (status & MAX172XX_STATUS_IMX)
                *health = POWER_SUPPLY_HEALTH_OVERCURRENT;
        else
                *health = POWER_SUPPLY_HEALTH_GOOD;

        /* Clear events which are not self-clearing to detect next events */
        if (status > 0 && status != MAX172XX_STATUS_IMX) {
                ret = regmap_set_bits(info->regmap, MAX172XX_STATUS,
                                      MAX172XX_STATUS_VMN |
                                      MAX172XX_STATUS_VMX |
                                      MAX172XX_STATUS_TMN |
                                      MAX172XX_STATUS_TMX);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int max1720x_battery_get_property(struct power_supply *psy,
                                         enum power_supply_property psp,
                                         union power_supply_propval *val)
{
        struct max1720x_device_info *info = power_supply_get_drvdata(psy);
        unsigned int reg_val;
        int ret = 0;

        switch (psp) {
        case POWER_SUPPLY_PROP_HEALTH:
                ret = max172xx_battery_health(info, &reg_val);
                val->intval = reg_val;
                break;
        case POWER_SUPPLY_PROP_PRESENT:
                /*
                 * POWER_SUPPLY_PROP_PRESENT will always readable via
                 * sysfs interface. Value return 0 if battery not
                 * present or unaccesable via I2c.
                 */
                ret = regmap_read(info->regmap, MAX172XX_STATUS, &reg_val);
                if (ret < 0) {
                        val->intval = 0;
                        return 0;
                }

                val->intval = !FIELD_GET(MAX172XX_STATUS_BAT_ABSENT, reg_val);
                break;
        case POWER_SUPPLY_PROP_CAPACITY:
                ret = regmap_read(info->regmap, MAX172XX_REPSOC, &reg_val);
                val->intval = max172xx_percent_to_ps(reg_val);
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                ret = regmap_read(info->regmap, MAX172XX_BATT, &reg_val);
                val->intval = max172xx_voltage_to_ps(reg_val);
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
                ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
                val->intval = max172xx_capacity_to_ps(reg_val, info);
                break;
        case POWER_SUPPLY_PROP_CHARGE_AVG:
                ret = regmap_read(info->regmap, MAX172XX_REPCAP, &reg_val);
                val->intval = max172xx_capacity_to_ps(reg_val, info);
                break;
        case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
                ret = regmap_read(info->regmap, MAX172XX_TTE, &reg_val);
                val->intval = max172xx_time_to_ps(reg_val);
                break;
        case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
                ret = regmap_read(info->regmap, MAX172XX_TTF, &reg_val);
                val->intval = max172xx_time_to_ps(reg_val);
                break;
        case POWER_SUPPLY_PROP_TEMP:
                ret = regmap_read(info->regmap, MAX172XX_TEMP, &reg_val);
                val->intval = max172xx_temperature_to_ps(reg_val);
                break;
        case POWER_SUPPLY_PROP_CURRENT_NOW:
                ret = regmap_read(info->regmap, MAX172XX_CURRENT, &reg_val);
                val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
                break;
        case POWER_SUPPLY_PROP_CURRENT_AVG:
                ret = regmap_read(info->regmap, MAX172XX_AVG_CURRENT, &reg_val);
                val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL:
                ret = regmap_read(info->regmap, MAX172XX_FULL_CAP, &reg_val);
                val->intval = max172xx_capacity_to_ps(reg_val, info);
                break;
        case POWER_SUPPLY_PROP_MODEL_NAME:
                ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);
                if (ret)
                        return ret;
                reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
                if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
                        val->strval = max17201_model;
                else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
                        val->strval = max17205_model;
                else
                        return -ENODEV;
                break;
        case POWER_SUPPLY_PROP_MANUFACTURER:
                val->strval = max1720x_manufacturer;
                break;
        default:
                return -EINVAL;
        }

        return ret;
}

static int max1720x_read_temp(struct device *dev, u8 reg, char *buf)
{
        struct power_supply *psy = dev_get_drvdata(dev);
        struct max1720x_device_info *info = power_supply_get_drvdata(psy);
        unsigned int val;
        int ret;

        ret = regmap_read(info->regmap_nv, reg, &val);
        if (ret < 0)
                return ret;

        /*
         * Temperature in degrees Celsius starting at absolute zero, -273C or
         * 0K with an LSb of 0.1C
         */
        return sysfs_emit(buf, "%d\n", val - 2730);
}

static ssize_t temp_ain1_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
{
        return max1720x_read_temp(dev, MAX172XX_TEMP1, buf);
}

static ssize_t temp_ain2_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
{
        return max1720x_read_temp(dev, MAX172XX_TEMP2, buf);
}

static ssize_t temp_int_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        return max1720x_read_temp(dev, MAX172XX_INT_TEMP, buf);
}

static DEVICE_ATTR_RO(temp_ain1);
static DEVICE_ATTR_RO(temp_ain2);
static DEVICE_ATTR_RO(temp_int);

static struct attribute *max1720x_attrs[] = {
        &dev_attr_temp_ain1.attr,
        &dev_attr_temp_ain2.attr,
        &dev_attr_temp_int.attr,
        NULL
};
ATTRIBUTE_GROUPS(max1720x);

static
int max1720x_nvmem_reg_read(void *priv, unsigned int off, void *val, size_t len)
{
        struct max1720x_device_info *info = priv;
        unsigned int reg = MAX1720X_NXTABLE0 + (off / 2);

        return regmap_bulk_read(info->regmap_nv, reg, val, len / 2);
}

static void max1720x_unregister_ancillary(void *data)
{
        struct max1720x_device_info *info = data;

        i2c_unregister_device(info->ancillary);
}

static int max1720x_probe_nvmem(struct i2c_client *client,
                                struct max1720x_device_info *info)
{
        struct device *dev = &client->dev;
        struct nvmem_config nvmem_config = {
                .dev = dev,
                .name = "max1720x_nvmem",
                .cells = max1720x_nvmem_cells,
                .ncells = ARRAY_SIZE(max1720x_nvmem_cells),
                .read_only = true,
                .root_only = true,
                .reg_read = max1720x_nvmem_reg_read,
                .size = ARRAY_SIZE(max1720x_nvmem_cells) * 2,
                .word_size = 2,
                .stride = 2,
                .priv = info,
        };
        struct nvmem_device *nvmem;
        unsigned int val;
        int ret;

        info->ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
        if (IS_ERR(info->ancillary)) {
                dev_err(dev, "Failed to initialize ancillary i2c device\n");
                return PTR_ERR(info->ancillary);
        }

        ret = devm_add_action_or_reset(dev, max1720x_unregister_ancillary, info);
        if (ret) {
                dev_err(dev, "Failed to add unregister callback\n");
                return ret;
        }

        info->regmap_nv = devm_regmap_init_i2c(info->ancillary,
                                               &max1720x_nvmem_regmap_cfg);
        if (IS_ERR(info->regmap_nv)) {
                dev_err(dev, "regmap initialization of nvmem failed\n");
                return PTR_ERR(info->regmap_nv);
        }

        ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
        if (ret < 0) {
                dev_err(dev, "Failed to read sense resistor value\n");
                return ret;
        }

        info->rsense = val;
        if (!info->rsense) {
                dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
                info->rsense = 1000; /* in regs in 10^-5 */
        }

        nvmem = devm_nvmem_register(dev, &nvmem_config);
        if (IS_ERR(nvmem)) {
                dev_err(dev, "Could not register nvmem!");
                return PTR_ERR(nvmem);
        }

        return 0;
}

static const struct power_supply_desc max1720x_bat_desc = {
        .name = "max1720x",
        .no_thermal = true,
        .type = POWER_SUPPLY_TYPE_BATTERY,
        .properties = max1720x_battery_props,
        .num_properties = ARRAY_SIZE(max1720x_battery_props),
        .get_property = max1720x_battery_get_property,
};

static int max1720x_probe(struct i2c_client *client)
{
        struct power_supply_config psy_cfg = {};
        struct device *dev = &client->dev;
        struct max1720x_device_info *info;
        struct power_supply *bat;
        int ret;

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

        psy_cfg.drv_data = info;
        psy_cfg.fwnode = dev_fwnode(dev);
        psy_cfg.attr_grp = max1720x_groups;
        i2c_set_clientdata(client, info);
        info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
        if (IS_ERR(info->regmap))
                return dev_err_probe(dev, PTR_ERR(info->regmap),
                                     "regmap initialization failed\n");

        ret = max1720x_probe_nvmem(client, info);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to probe nvmem\n");

        bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
        if (IS_ERR(bat))
                return dev_err_probe(dev, PTR_ERR(bat),
                                     "Failed to register power supply\n");

        return 0;
}

static const struct of_device_id max1720x_of_match[] = {
        { .compatible = "maxim,max17201" },
        {}
};
MODULE_DEVICE_TABLE(of, max1720x_of_match);

static struct i2c_driver max1720x_i2c_driver = {
        .driver = {
                .name = "max1720x",
                .of_match_table = max1720x_of_match,
        },
        .probe = max1720x_probe,
};
module_i2c_driver(max1720x_i2c_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dimitri Fedrau <dima.fedrau@gmail.com>");
MODULE_DESCRIPTION("Maxim MAX17201/MAX17205 Fuel Gauge IC driver");