// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Spreadtrum Communications Inc.

#include <linux/gpio/consumer.h>
#include <linux/iio/consumer.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#include <linux/slab.h>

/* PMIC global control registers definition */
#define SC27XX_MODULE_EN0               0xc08
#define SC27XX_CLK_EN0                  0xc18
#define SC27XX_FGU_EN                   BIT(7)
#define SC27XX_FGU_RTC_EN               BIT(6)

/* FGU registers definition */
#define SC27XX_FGU_START                0x0
#define SC27XX_FGU_CONFIG               0x4
#define SC27XX_FGU_ADC_CONFIG           0x8
#define SC27XX_FGU_STATUS               0xc
#define SC27XX_FGU_INT_EN               0x10
#define SC27XX_FGU_INT_CLR              0x14
#define SC27XX_FGU_INT_STS              0x1c
#define SC27XX_FGU_VOLTAGE              0x20
#define SC27XX_FGU_OCV                  0x24
#define SC27XX_FGU_POCV                 0x28
#define SC27XX_FGU_CURRENT              0x2c
#define SC27XX_FGU_LOW_OVERLOAD         0x34
#define SC27XX_FGU_CLBCNT_SETH          0x50
#define SC27XX_FGU_CLBCNT_SETL          0x54
#define SC27XX_FGU_CLBCNT_DELTH         0x58
#define SC27XX_FGU_CLBCNT_DELTL         0x5c
#define SC27XX_FGU_CLBCNT_VALH          0x68
#define SC27XX_FGU_CLBCNT_VALL          0x6c
#define SC27XX_FGU_CLBCNT_QMAXL         0x74
#define SC27XX_FGU_USER_AREA_SET        0xa0
#define SC27XX_FGU_USER_AREA_CLEAR      0xa4
#define SC27XX_FGU_USER_AREA_STATUS     0xa8
#define SC27XX_FGU_VOLTAGE_BUF          0xd0
#define SC27XX_FGU_CURRENT_BUF          0xf0

#define SC27XX_WRITE_SELCLB_EN          BIT(0)
#define SC27XX_FGU_CLBCNT_MASK          GENMASK(15, 0)
#define SC27XX_FGU_CLBCNT_SHIFT         16
#define SC27XX_FGU_LOW_OVERLOAD_MASK    GENMASK(12, 0)

#define SC27XX_FGU_INT_MASK             GENMASK(9, 0)
#define SC27XX_FGU_LOW_OVERLOAD_INT     BIT(0)
#define SC27XX_FGU_CLBCNT_DELTA_INT     BIT(2)

#define SC27XX_FGU_MODE_AREA_MASK       GENMASK(15, 12)
#define SC27XX_FGU_CAP_AREA_MASK        GENMASK(11, 0)
#define SC27XX_FGU_MODE_AREA_SHIFT      12

#define SC27XX_FGU_FIRST_POWERTON       GENMASK(3, 0)
#define SC27XX_FGU_DEFAULT_CAP          GENMASK(11, 0)
#define SC27XX_FGU_NORMAIL_POWERTON     0x5

#define SC27XX_FGU_CUR_BASIC_ADC        8192
#define SC27XX_FGU_SAMPLE_HZ            2
/* micro Ohms */
#define SC27XX_FGU_IDEAL_RESISTANCE     20000

/*
 * struct sc27xx_fgu_data: describe the FGU device
 * @regmap: regmap for register access
 * @dev: platform device
 * @battery: battery power supply
 * @base: the base offset for the controller
 * @lock: protect the structure
 * @gpiod: GPIO for battery detection
 * @channel: IIO channel to get battery temperature
 * @charge_chan: IIO channel to get charge voltage
 * @internal_resist: the battery internal resistance in mOhm
 * @total_cap: the total capacity of the battery in mAh
 * @init_cap: the initial capacity of the battery in mAh
 * @alarm_cap: the alarm capacity
 * @init_clbcnt: the initial coulomb counter
 * @max_volt: the maximum constant input voltage in millivolt
 * @min_volt: the minimum drained battery voltage in microvolt
 * @boot_volt: the voltage measured during boot in microvolt
 * @table_len: the capacity table length
 * @resist_table_len: the resistance table length
 * @cur_1000ma_adc: ADC value corresponding to 1000 mA
 * @vol_1000mv_adc: ADC value corresponding to 1000 mV
 * @calib_resist: the real resistance of coulomb counter chip in uOhm
 * @cap_table: capacity table with corresponding ocv
 * @resist_table: resistance percent table with corresponding temperature
 */
struct sc27xx_fgu_data {
        struct regmap *regmap;
        struct device *dev;
        struct power_supply *battery;
        u32 base;
        struct mutex lock;
        struct gpio_desc *gpiod;
        struct iio_channel *channel;
        struct iio_channel *charge_chan;
        bool bat_present;
        int internal_resist;
        int total_cap;
        int init_cap;
        int alarm_cap;
        int init_clbcnt;
        int max_volt;
        int min_volt;
        int boot_volt;
        int table_len;
        int resist_table_len;
        int cur_1000ma_adc;
        int vol_1000mv_adc;
        int calib_resist;
        struct power_supply_battery_ocv_table *cap_table;
        struct power_supply_resistance_temp_table *resist_table;
};

static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity);
static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
                                            int cap, bool int_mode);
static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap);
static int sc27xx_fgu_get_temp(struct sc27xx_fgu_data *data, int *temp);

static const char * const sc27xx_charger_supply_name[] = {
        "sc2731_charger",
        "sc2720_charger",
        "sc2721_charger",
        "sc2723_charger",
};

static int sc27xx_fgu_adc_to_current(struct sc27xx_fgu_data *data, s64 adc)
{
        return DIV_S64_ROUND_CLOSEST(adc * 1000, data->cur_1000ma_adc);
}

static int sc27xx_fgu_adc_to_voltage(struct sc27xx_fgu_data *data, s64 adc)
{
        return DIV_S64_ROUND_CLOSEST(adc * 1000, data->vol_1000mv_adc);
}

static int sc27xx_fgu_voltage_to_adc(struct sc27xx_fgu_data *data, int vol)
{
        return DIV_ROUND_CLOSEST(vol * data->vol_1000mv_adc, 1000);
}

static bool sc27xx_fgu_is_first_poweron(struct sc27xx_fgu_data *data)
{
        int ret, status, cap, mode;

        ret = regmap_read(data->regmap,
                          data->base + SC27XX_FGU_USER_AREA_STATUS, &status);
        if (ret)
                return false;

        /*
         * We use low 4 bits to save the last battery capacity and high 12 bits
         * to save the system boot mode.
         */
        mode = (status & SC27XX_FGU_MODE_AREA_MASK) >> SC27XX_FGU_MODE_AREA_SHIFT;
        cap = status & SC27XX_FGU_CAP_AREA_MASK;

        /*
         * When FGU has been powered down, the user area registers became
         * default value (0xffff), which can be used to valid if the system is
         * first power on or not.
         */
        if (mode == SC27XX_FGU_FIRST_POWERTON || cap == SC27XX_FGU_DEFAULT_CAP)
                return true;

        return false;
}

static int sc27xx_fgu_save_boot_mode(struct sc27xx_fgu_data *data,
                                     int boot_mode)
{
        int ret;

        ret = regmap_update_bits(data->regmap,
                                 data->base + SC27XX_FGU_USER_AREA_CLEAR,
                                 SC27XX_FGU_MODE_AREA_MASK,
                                 SC27XX_FGU_MODE_AREA_MASK);
        if (ret)
                return ret;

        /*
         * Since the user area registers are put on power always-on region,
         * then these registers changing time will be a little long. Thus
         * here we should delay 200us to wait until values are updated
         * successfully according to the datasheet.
         */
        udelay(200);

        ret = regmap_update_bits(data->regmap,
                                 data->base + SC27XX_FGU_USER_AREA_SET,
                                 SC27XX_FGU_MODE_AREA_MASK,
                                 boot_mode << SC27XX_FGU_MODE_AREA_SHIFT);
        if (ret)
                return ret;

        /*
         * Since the user area registers are put on power always-on region,
         * then these registers changing time will be a little long. Thus
         * here we should delay 200us to wait until values are updated
         * successfully according to the datasheet.
         */
        udelay(200);

        /*
         * According to the datasheet, we should set the USER_AREA_CLEAR to 0 to
         * make the user area data available, otherwise we can not save the user
         * area data.
         */
        return regmap_update_bits(data->regmap,
                                  data->base + SC27XX_FGU_USER_AREA_CLEAR,
                                  SC27XX_FGU_MODE_AREA_MASK, 0);
}

static int sc27xx_fgu_save_last_cap(struct sc27xx_fgu_data *data, int cap)
{
        int ret;

        ret = regmap_update_bits(data->regmap,
                                 data->base + SC27XX_FGU_USER_AREA_CLEAR,
                                 SC27XX_FGU_CAP_AREA_MASK,
                                 SC27XX_FGU_CAP_AREA_MASK);
        if (ret)
                return ret;

        /*
         * Since the user area registers are put on power always-on region,
         * then these registers changing time will be a little long. Thus
         * here we should delay 200us to wait until values are updated
         * successfully according to the datasheet.
         */
        udelay(200);

        ret = regmap_update_bits(data->regmap,
                                 data->base + SC27XX_FGU_USER_AREA_SET,
                                 SC27XX_FGU_CAP_AREA_MASK, cap);
        if (ret)
                return ret;

        /*
         * Since the user area registers are put on power always-on region,
         * then these registers changing time will be a little long. Thus
         * here we should delay 200us to wait until values are updated
         * successfully according to the datasheet.
         */
        udelay(200);

        /*
         * According to the datasheet, we should set the USER_AREA_CLEAR to 0 to
         * make the user area data available, otherwise we can not save the user
         * area data.
         */
        return regmap_update_bits(data->regmap,
                                  data->base + SC27XX_FGU_USER_AREA_CLEAR,
                                  SC27XX_FGU_CAP_AREA_MASK, 0);
}

static int sc27xx_fgu_read_last_cap(struct sc27xx_fgu_data *data, int *cap)
{
        int ret, value;

        ret = regmap_read(data->regmap,
                          data->base + SC27XX_FGU_USER_AREA_STATUS, &value);
        if (ret)
                return ret;

        *cap = value & SC27XX_FGU_CAP_AREA_MASK;
        return 0;
}

/*
 * When system boots on, we can not read battery capacity from coulomb
 * registers, since now the coulomb registers are invalid. So we should
 * calculate the battery open circuit voltage, and get current battery
 * capacity according to the capacity table.
 */
static int sc27xx_fgu_get_boot_capacity(struct sc27xx_fgu_data *data, int *cap)
{
        int volt, cur, oci, ocv, ret;
        bool is_first_poweron = sc27xx_fgu_is_first_poweron(data);

        /*
         * If system is not the first power on, we should use the last saved
         * battery capacity as the initial battery capacity. Otherwise we should
         * re-calculate the initial battery capacity.
         */
        if (!is_first_poweron) {
                ret = sc27xx_fgu_read_last_cap(data, cap);
                if (ret)
                        return ret;

                return sc27xx_fgu_save_boot_mode(data, SC27XX_FGU_NORMAIL_POWERTON);
        }

        /*
         * After system booting on, the SC27XX_FGU_CLBCNT_QMAXL register saved
         * the first sampled open circuit current.
         */
        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CLBCNT_QMAXL,
                          &cur);
        if (ret)
                return ret;

        cur <<= 1;
        oci = sc27xx_fgu_adc_to_current(data, cur - SC27XX_FGU_CUR_BASIC_ADC);

        /*
         * Should get the OCV from SC27XX_FGU_POCV register at the system
         * beginning. It is ADC values reading from registers which need to
         * convert the corresponding voltage.
         */
        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_POCV, &volt);
        if (ret)
                return ret;

        volt = sc27xx_fgu_adc_to_voltage(data, volt);
        ocv = volt * 1000 - oci * data->internal_resist;
        data->boot_volt = ocv;

        /*
         * Parse the capacity table to look up the correct capacity percent
         * according to current battery's corresponding OCV values.
         */
        *cap = power_supply_ocv2cap_simple(data->cap_table, data->table_len,
                                           ocv);

        ret = sc27xx_fgu_save_last_cap(data, *cap);
        if (ret)
                return ret;

        return sc27xx_fgu_save_boot_mode(data, SC27XX_FGU_NORMAIL_POWERTON);
}

static int sc27xx_fgu_set_clbcnt(struct sc27xx_fgu_data *data, int clbcnt)
{
        int ret;

        ret = regmap_update_bits(data->regmap,
                                 data->base + SC27XX_FGU_CLBCNT_SETL,
                                 SC27XX_FGU_CLBCNT_MASK, clbcnt);
        if (ret)
                return ret;

        ret = regmap_update_bits(data->regmap,
                                 data->base + SC27XX_FGU_CLBCNT_SETH,
                                 SC27XX_FGU_CLBCNT_MASK,
                                 clbcnt >> SC27XX_FGU_CLBCNT_SHIFT);
        if (ret)
                return ret;

        return regmap_update_bits(data->regmap, data->base + SC27XX_FGU_START,
                                 SC27XX_WRITE_SELCLB_EN,
                                 SC27XX_WRITE_SELCLB_EN);
}

static int sc27xx_fgu_get_clbcnt(struct sc27xx_fgu_data *data, int *clb_cnt)
{
        int ccl, cch, ret;

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CLBCNT_VALL,
                          &ccl);
        if (ret)
                return ret;

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CLBCNT_VALH,
                          &cch);
        if (ret)
                return ret;

        *clb_cnt = ccl & SC27XX_FGU_CLBCNT_MASK;
        *clb_cnt |= (cch & SC27XX_FGU_CLBCNT_MASK) << SC27XX_FGU_CLBCNT_SHIFT;

        return 0;
}

static int sc27xx_fgu_get_vol_now(struct sc27xx_fgu_data *data, int *val)
{
        int ret;
        u32 vol;

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_VOLTAGE_BUF,
                          &vol);
        if (ret)
                return ret;

        /*
         * It is ADC values reading from registers which need to convert to
         * corresponding voltage values.
         */
        *val = sc27xx_fgu_adc_to_voltage(data, vol);

        return 0;
}

static int sc27xx_fgu_get_cur_now(struct sc27xx_fgu_data *data, int *val)
{
        int ret;
        u32 cur;

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CURRENT_BUF,
                          &cur);
        if (ret)
                return ret;

        /*
         * It is ADC values reading from registers which need to convert to
         * corresponding current values.
         */
        *val = sc27xx_fgu_adc_to_current(data, cur - SC27XX_FGU_CUR_BASIC_ADC);

        return 0;
}

static int sc27xx_fgu_get_capacity(struct sc27xx_fgu_data *data, int *cap)
{
        int ret, cur_clbcnt, delta_clbcnt, delta_cap, temp;

        /* Get current coulomb counters firstly */
        ret = sc27xx_fgu_get_clbcnt(data, &cur_clbcnt);
        if (ret)
                return ret;

        delta_clbcnt = cur_clbcnt - data->init_clbcnt;

        /*
         * Convert coulomb counter to delta capacity (mAh), and set multiplier
         * as 10 to improve the precision.
         */
        temp = DIV_ROUND_CLOSEST(delta_clbcnt * 10, 36 * SC27XX_FGU_SAMPLE_HZ);
        temp = sc27xx_fgu_adc_to_current(data, temp / 1000);

        /*
         * Convert to capacity percent of the battery total capacity,
         * and multiplier is 100 too.
         */
        delta_cap = DIV_ROUND_CLOSEST(temp * 100, data->total_cap);
        *cap = delta_cap + data->init_cap;

        /* Calibrate the battery capacity in a normal range. */
        sc27xx_fgu_capacity_calibration(data, *cap, false);

        return 0;
}

static int sc27xx_fgu_get_vbat_vol(struct sc27xx_fgu_data *data, int *val)
{
        int ret, vol;

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_VOLTAGE, &vol);
        if (ret)
                return ret;

        /*
         * It is ADC values reading from registers which need to convert to
         * corresponding voltage values.
         */
        *val = sc27xx_fgu_adc_to_voltage(data, vol);

        return 0;
}

static int sc27xx_fgu_get_current(struct sc27xx_fgu_data *data, int *val)
{
        int ret, cur;

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CURRENT, &cur);
        if (ret)
                return ret;

        /*
         * It is ADC values reading from registers which need to convert to
         * corresponding current values.
         */
        *val = sc27xx_fgu_adc_to_current(data, cur - SC27XX_FGU_CUR_BASIC_ADC);

        return 0;
}

static int sc27xx_fgu_get_vbat_ocv(struct sc27xx_fgu_data *data, int *val)
{
        int vol, cur, ret, temp, resistance;

        ret = sc27xx_fgu_get_vbat_vol(data, &vol);
        if (ret)
                return ret;

        ret = sc27xx_fgu_get_current(data, &cur);
        if (ret)
                return ret;

        resistance = data->internal_resist;
        if (data->resist_table_len > 0) {
                ret = sc27xx_fgu_get_temp(data, &temp);
                if (ret)
                        return ret;

                resistance = power_supply_temp2resist_simple(data->resist_table,
                                                data->resist_table_len, temp);
                resistance = data->internal_resist * resistance / 100;
        }

        /* Return the battery OCV in micro volts. */
        *val = vol * 1000 - cur * resistance;

        return 0;
}

static int sc27xx_fgu_get_charge_vol(struct sc27xx_fgu_data *data, int *val)
{
        int ret, vol;

        ret = iio_read_channel_processed(data->charge_chan, &vol);
        if (ret < 0)
                return ret;

        *val = vol * 1000;
        return 0;
}

static int sc27xx_fgu_get_temp(struct sc27xx_fgu_data *data, int *temp)
{
        return iio_read_channel_processed(data->channel, temp);
}

static int sc27xx_fgu_get_health(struct sc27xx_fgu_data *data, int *health)
{
        int ret, vol;

        ret = sc27xx_fgu_get_vbat_vol(data, &vol);
        if (ret)
                return ret;

        if (vol > data->max_volt)
                *health = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
        else
                *health = POWER_SUPPLY_HEALTH_GOOD;

        return 0;
}

static int sc27xx_fgu_get_status(struct sc27xx_fgu_data *data, int *status)
{
        union power_supply_propval val;
        struct power_supply *psy;
        int i, ret = -EINVAL;

        for (i = 0; i < ARRAY_SIZE(sc27xx_charger_supply_name); i++) {
                psy = power_supply_get_by_name(sc27xx_charger_supply_name[i]);
                if (!psy)
                        continue;

                ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS,
                                                &val);
                power_supply_put(psy);
                if (ret)
                        return ret;

                *status = val.intval;
        }

        return ret;
}

static int sc27xx_fgu_get_property(struct power_supply *psy,
                                   enum power_supply_property psp,
                                   union power_supply_propval *val)
{
        struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
        int ret = 0;
        int value;

        mutex_lock(&data->lock);

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                ret = sc27xx_fgu_get_status(data, &value);
                if (ret)
                        goto error;

                val->intval = value;
                break;

        case POWER_SUPPLY_PROP_HEALTH:
                ret = sc27xx_fgu_get_health(data, &value);
                if (ret)
                        goto error;

                val->intval = value;
                break;

        case POWER_SUPPLY_PROP_PRESENT:
                val->intval = data->bat_present;
                break;

        case POWER_SUPPLY_PROP_TEMP:
                ret = sc27xx_fgu_get_temp(data, &value);
                if (ret)
                        goto error;

                val->intval = value;
                break;

        case POWER_SUPPLY_PROP_TECHNOLOGY:
                val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
                break;

        case POWER_SUPPLY_PROP_CAPACITY:
                ret = sc27xx_fgu_get_capacity(data, &value);
                if (ret)
                        goto error;

                val->intval = value;
                break;

        case POWER_SUPPLY_PROP_VOLTAGE_AVG:
                ret = sc27xx_fgu_get_vbat_vol(data, &value);
                if (ret)
                        goto error;

                val->intval = value * 1000;
                break;

        case POWER_SUPPLY_PROP_VOLTAGE_OCV:
                ret = sc27xx_fgu_get_vbat_ocv(data, &value);
                if (ret)
                        goto error;

                val->intval = value;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                ret = sc27xx_fgu_get_charge_vol(data, &value);
                if (ret)
                        goto error;

                val->intval = value;
                break;

        case POWER_SUPPLY_PROP_CURRENT_AVG:
                ret = sc27xx_fgu_get_current(data, &value);
                if (ret)
                        goto error;

                val->intval = value * 1000;
                break;

        case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
                val->intval = data->total_cap * 1000;
                break;

        case POWER_SUPPLY_PROP_CHARGE_NOW:
                ret = sc27xx_fgu_get_clbcnt(data, &value);
                if (ret)
                        goto error;

                value = DIV_ROUND_CLOSEST(value * 10,
                                          36 * SC27XX_FGU_SAMPLE_HZ);
                val->intval = sc27xx_fgu_adc_to_current(data, value);

                break;

        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                ret = sc27xx_fgu_get_vol_now(data, &value);
                if (ret)
                        goto error;

                val->intval = value * 1000;
                break;

        case POWER_SUPPLY_PROP_CURRENT_NOW:
                ret = sc27xx_fgu_get_cur_now(data, &value);
                if (ret)
                        goto error;

                val->intval = value * 1000;
                break;

        case POWER_SUPPLY_PROP_VOLTAGE_BOOT:
                val->intval = data->boot_volt;
                break;

        default:
                ret = -EINVAL;
                break;
        }

error:
        mutex_unlock(&data->lock);
        return ret;
}

static int sc27xx_fgu_set_property(struct power_supply *psy,
                                   enum power_supply_property psp,
                                   const union power_supply_propval *val)
{
        struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
        int ret;

        mutex_lock(&data->lock);

        switch (psp) {
        case POWER_SUPPLY_PROP_CAPACITY:
                ret = sc27xx_fgu_save_last_cap(data, val->intval);
                if (ret < 0)
                        dev_err(data->dev, "failed to save battery capacity\n");
                break;

        case POWER_SUPPLY_PROP_CALIBRATE:
                sc27xx_fgu_adjust_cap(data, val->intval);
                ret = 0;
                break;

        case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
                data->total_cap = val->intval / 1000;
                ret = 0;
                break;

        default:
                ret = -EINVAL;
        }

        mutex_unlock(&data->lock);

        return ret;
}

static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
                                            enum power_supply_property psp)
{
        return psp == POWER_SUPPLY_PROP_CAPACITY ||
                psp == POWER_SUPPLY_PROP_CALIBRATE ||
                psp == POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN;
}

static enum power_supply_property sc27xx_fgu_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_HEALTH,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_TEMP,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_VOLTAGE_OCV,
        POWER_SUPPLY_PROP_VOLTAGE_AVG,
        POWER_SUPPLY_PROP_VOLTAGE_BOOT,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CURRENT_AVG,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
        POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
        POWER_SUPPLY_PROP_CALIBRATE,
        POWER_SUPPLY_PROP_CHARGE_NOW
};

static const struct power_supply_desc sc27xx_fgu_desc = {
        .name                   = "sc27xx-fgu",
        .type                   = POWER_SUPPLY_TYPE_BATTERY,
        .properties             = sc27xx_fgu_props,
        .num_properties         = ARRAY_SIZE(sc27xx_fgu_props),
        .get_property           = sc27xx_fgu_get_property,
        .set_property           = sc27xx_fgu_set_property,
        .external_power_changed = power_supply_changed,
        .property_is_writeable  = sc27xx_fgu_property_is_writeable,
        .no_thermal             = true,
};

static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap)
{
        int ret;

        data->init_cap = cap;
        ret = sc27xx_fgu_get_clbcnt(data, &data->init_clbcnt);
        if (ret)
                dev_err(data->dev, "failed to get init coulomb counter\n");
}

static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
                                            int cap, bool int_mode)
{
        int ret, ocv, chg_sts, adc;

        ret = sc27xx_fgu_get_vbat_ocv(data, &ocv);
        if (ret) {
                dev_err(data->dev, "get battery ocv error.\n");
                return;
        }

        ret = sc27xx_fgu_get_status(data, &chg_sts);
        if (ret) {
                dev_err(data->dev, "get charger status error.\n");
                return;
        }

        /*
         * If we are in charging mode, then we do not need to calibrate the
         * lower capacity.
         */
        if (chg_sts == POWER_SUPPLY_STATUS_CHARGING)
                return;

        if ((ocv > data->cap_table[0].ocv && cap < 100) || cap > 100) {
                /*
                 * If current OCV value is larger than the max OCV value in
                 * OCV table, or the current capacity is larger than 100,
                 * we should force the inititial capacity to 100.
                 */
                sc27xx_fgu_adjust_cap(data, 100);
        } else if (ocv <= data->cap_table[data->table_len - 1].ocv) {
                /*
                 * If current OCV value is leass than the minimum OCV value in
                 * OCV table, we should force the inititial capacity to 0.
                 */
                sc27xx_fgu_adjust_cap(data, 0);
        } else if ((ocv > data->cap_table[data->table_len - 1].ocv && cap <= 0) ||
                   (ocv > data->min_volt && cap <= data->alarm_cap)) {
                /*
                 * If current OCV value is not matchable with current capacity,
                 * we should re-calculate current capacity by looking up the
                 * OCV table.
                 */
                int cur_cap = power_supply_ocv2cap_simple(data->cap_table,
                                                          data->table_len, ocv);

                sc27xx_fgu_adjust_cap(data, cur_cap);
        } else if (ocv <= data->min_volt) {
                /*
                 * If current OCV value is less than the low alarm voltage, but
                 * current capacity is larger than the alarm capacity, we should
                 * adjust the inititial capacity to alarm capacity.
                 */
                if (cap > data->alarm_cap) {
                        sc27xx_fgu_adjust_cap(data, data->alarm_cap);
                } else {
                        int cur_cap;

                        /*
                         * If current capacity is equal with 0 or less than 0
                         * (some error occurs), we should adjust inititial
                         * capacity to the capacity corresponding to current OCV
                         * value.
                         */
                        cur_cap = power_supply_ocv2cap_simple(data->cap_table,
                                                              data->table_len,
                                                              ocv);
                        sc27xx_fgu_adjust_cap(data, cur_cap);
                }

                if (!int_mode)
                        return;

                /*
                 * After adjusting the battery capacity, we should set the
                 * lowest alarm voltage instead.
                 */
                data->min_volt = data->cap_table[data->table_len - 1].ocv;
                data->alarm_cap = power_supply_ocv2cap_simple(data->cap_table,
                                                              data->table_len,
                                                              data->min_volt);

                adc = sc27xx_fgu_voltage_to_adc(data, data->min_volt / 1000);
                regmap_update_bits(data->regmap,
                                   data->base + SC27XX_FGU_LOW_OVERLOAD,
                                   SC27XX_FGU_LOW_OVERLOAD_MASK, adc);
        }
}

static irqreturn_t sc27xx_fgu_interrupt(int irq, void *dev_id)
{
        struct sc27xx_fgu_data *data = dev_id;
        int ret, cap;
        u32 status;

        mutex_lock(&data->lock);

        ret = regmap_read(data->regmap, data->base + SC27XX_FGU_INT_STS,
                          &status);
        if (ret)
                goto out;

        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_CLR,
                                 status, status);
        if (ret)
                goto out;

        /*
         * When low overload voltage interrupt happens, we should calibrate the
         * battery capacity in lower voltage stage.
         */
        if (!(status & SC27XX_FGU_LOW_OVERLOAD_INT))
                goto out;

        ret = sc27xx_fgu_get_capacity(data, &cap);
        if (ret)
                goto out;

        sc27xx_fgu_capacity_calibration(data, cap, true);

out:
        mutex_unlock(&data->lock);

        power_supply_changed(data->battery);
        return IRQ_HANDLED;
}

static irqreturn_t sc27xx_fgu_bat_detection(int irq, void *dev_id)
{
        struct sc27xx_fgu_data *data = dev_id;
        int state;

        mutex_lock(&data->lock);

        state = gpiod_get_value_cansleep(data->gpiod);
        if (state < 0) {
                dev_err(data->dev, "failed to get gpio state\n");
                mutex_unlock(&data->lock);
                return IRQ_RETVAL(state);
        }

        data->bat_present = !!state;

        mutex_unlock(&data->lock);

        power_supply_changed(data->battery);
        return IRQ_HANDLED;
}

static void sc27xx_fgu_disable(void *_data)
{
        struct sc27xx_fgu_data *data = _data;

        regmap_update_bits(data->regmap, SC27XX_CLK_EN0, SC27XX_FGU_RTC_EN, 0);
        regmap_update_bits(data->regmap, SC27XX_MODULE_EN0, SC27XX_FGU_EN, 0);
}

static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity)
{
        /*
         * Get current capacity (mAh) = battery total capacity (mAh) *
         * current capacity percent (capacity / 100).
         */
        int cur_cap = DIV_ROUND_CLOSEST(data->total_cap * capacity, 100);

        /*
         * Convert current capacity (mAh) to coulomb counter according to the
         * formula: 1 mAh =3.6 coulomb.
         */
        return DIV_ROUND_CLOSEST(cur_cap * 36 * data->cur_1000ma_adc * SC27XX_FGU_SAMPLE_HZ, 10);
}

static int sc27xx_fgu_calibration(struct sc27xx_fgu_data *data)
{
        struct nvmem_cell *cell;
        int calib_data, cal_4200mv;
        void *buf;
        size_t len;

        cell = nvmem_cell_get(data->dev, "fgu_calib");
        if (IS_ERR(cell))
                return PTR_ERR(cell);

        buf = nvmem_cell_read(cell, &len);
        nvmem_cell_put(cell);

        if (IS_ERR(buf))
                return PTR_ERR(buf);

        memcpy(&calib_data, buf, min(len, sizeof(u32)));

        /*
         * Get the ADC value corresponding to 4200 mV from eFuse controller
         * according to below formula. Then convert to ADC values corresponding
         * to 1000 mV and 1000 mA.
         */
        cal_4200mv = (calib_data & 0x1ff) + 6963 - 4096 - 256;
        data->vol_1000mv_adc = DIV_ROUND_CLOSEST(cal_4200mv * 10, 42);
        data->cur_1000ma_adc =
                DIV_ROUND_CLOSEST(data->vol_1000mv_adc * 4 * data->calib_resist,
                                  SC27XX_FGU_IDEAL_RESISTANCE);

        kfree(buf);
        return 0;
}

static int sc27xx_fgu_hw_init(struct sc27xx_fgu_data *data)
{
        struct power_supply_battery_info *info;
        const struct power_supply_battery_ocv_table *table;
        int ret, delta_clbcnt, alarm_adc;

        ret = power_supply_get_battery_info(data->battery, &info);
        if (ret) {
                dev_err(data->dev, "failed to get battery information\n");
                return ret;
        }

        data->total_cap = info->charge_full_design_uah / 1000;
        data->max_volt = info->constant_charge_voltage_max_uv / 1000;
        data->internal_resist = info->factory_internal_resistance_uohm / 1000;
        data->min_volt = info->voltage_min_design_uv;

        /*
         * For SC27XX fuel gauge device, we only use one ocv-capacity
         * table in normal temperature 20 Celsius.
         */
        table = power_supply_find_ocv2cap_table(info, 20, &data->table_len);
        if (!table)
                return -EINVAL;

        data->cap_table = devm_kmemdup_array(data->dev, table, data->table_len,
                                             sizeof(*table), GFP_KERNEL);
        if (!data->cap_table) {
                power_supply_put_battery_info(data->battery, info);
                return -ENOMEM;
        }

        data->alarm_cap = power_supply_ocv2cap_simple(data->cap_table,
                                                      data->table_len,
                                                      data->min_volt);
        if (!data->alarm_cap)
                data->alarm_cap += 1;

        data->resist_table_len = info->resist_table_size;
        if (data->resist_table_len > 0) {
                data->resist_table = devm_kmemdup(data->dev, info->resist_table,
                                                  data->resist_table_len *
                                                  sizeof(struct power_supply_resistance_temp_table),
                                                  GFP_KERNEL);
                if (!data->resist_table) {
                        power_supply_put_battery_info(data->battery, info);
                        return -ENOMEM;
                }
        }

        power_supply_put_battery_info(data->battery, info);

        ret = sc27xx_fgu_calibration(data);
        if (ret)
                return ret;

        /* Enable the FGU module */
        ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN0,
                                 SC27XX_FGU_EN, SC27XX_FGU_EN);
        if (ret) {
                dev_err(data->dev, "failed to enable fgu\n");
                return ret;
        }

        /* Enable the FGU RTC clock to make it work */
        ret = regmap_update_bits(data->regmap, SC27XX_CLK_EN0,
                                 SC27XX_FGU_RTC_EN, SC27XX_FGU_RTC_EN);
        if (ret) {
                dev_err(data->dev, "failed to enable fgu RTC clock\n");
                goto disable_fgu;
        }

        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_CLR,
                                 SC27XX_FGU_INT_MASK, SC27XX_FGU_INT_MASK);
        if (ret) {
                dev_err(data->dev, "failed to clear interrupt status\n");
                goto disable_clk;
        }

        /*
         * Set the voltage low overload threshold, which means when the battery
         * voltage is lower than this threshold, the controller will generate
         * one interrupt to notify.
         */
        alarm_adc = sc27xx_fgu_voltage_to_adc(data, data->min_volt / 1000);
        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_LOW_OVERLOAD,
                                 SC27XX_FGU_LOW_OVERLOAD_MASK, alarm_adc);
        if (ret) {
                dev_err(data->dev, "failed to set fgu low overload\n");
                goto disable_clk;
        }

        /*
         * Set the coulomb counter delta threshold, that means when the coulomb
         * counter change is multiples of the delta threshold, the controller
         * will generate one interrupt to notify the users to update the battery
         * capacity. Now we set the delta threshold as a counter value of 1%
         * capacity.
         */
        delta_clbcnt = sc27xx_fgu_cap_to_clbcnt(data, 1);

        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_CLBCNT_DELTL,
                                 SC27XX_FGU_CLBCNT_MASK, delta_clbcnt);
        if (ret) {
                dev_err(data->dev, "failed to set low delta coulomb counter\n");
                goto disable_clk;
        }

        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_CLBCNT_DELTH,
                                 SC27XX_FGU_CLBCNT_MASK,
                                 delta_clbcnt >> SC27XX_FGU_CLBCNT_SHIFT);
        if (ret) {
                dev_err(data->dev, "failed to set high delta coulomb counter\n");
                goto disable_clk;
        }

        /*
         * Get the boot battery capacity when system powers on, which is used to
         * initialize the coulomb counter. After that, we can read the coulomb
         * counter to measure the battery capacity.
         */
        ret = sc27xx_fgu_get_boot_capacity(data, &data->init_cap);
        if (ret) {
                dev_err(data->dev, "failed to get boot capacity\n");
                goto disable_clk;
        }

        /*
         * Convert battery capacity to the corresponding initial coulomb counter
         * and set into coulomb counter registers.
         */
        data->init_clbcnt = sc27xx_fgu_cap_to_clbcnt(data, data->init_cap);
        ret = sc27xx_fgu_set_clbcnt(data, data->init_clbcnt);
        if (ret) {
                dev_err(data->dev, "failed to initialize coulomb counter\n");
                goto disable_clk;
        }

        return 0;

disable_clk:
        regmap_update_bits(data->regmap, SC27XX_CLK_EN0, SC27XX_FGU_RTC_EN, 0);
disable_fgu:
        regmap_update_bits(data->regmap, SC27XX_MODULE_EN0, SC27XX_FGU_EN, 0);

        return ret;
}

static int sc27xx_fgu_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct power_supply_config fgu_cfg = { };
        struct sc27xx_fgu_data *data;
        int ret, irq;

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

        data->regmap = dev_get_regmap(dev->parent, NULL);
        if (!data->regmap) {
                dev_err(dev, "failed to get regmap\n");
                return -ENODEV;
        }

        ret = device_property_read_u32(dev, "reg", &data->base);
        if (ret) {
                dev_err(dev, "failed to get fgu address\n");
                return ret;
        }

        ret = device_property_read_u32(&pdev->dev,
                                       "sprd,calib-resistance-micro-ohms",
                                       &data->calib_resist);
        if (ret) {
                dev_err(&pdev->dev,
                        "failed to get fgu calibration resistance\n");
                return ret;
        }

        data->channel = devm_iio_channel_get(dev, "bat-temp");
        if (IS_ERR(data->channel)) {
                dev_err(dev, "failed to get IIO channel\n");
                return PTR_ERR(data->channel);
        }

        data->charge_chan = devm_iio_channel_get(dev, "charge-vol");
        if (IS_ERR(data->charge_chan)) {
                dev_err(dev, "failed to get charge IIO channel\n");
                return PTR_ERR(data->charge_chan);
        }

        data->gpiod = devm_gpiod_get(dev, "battery-detect", GPIOD_IN);
        if (IS_ERR(data->gpiod)) {
                data->gpiod = devm_gpiod_get(dev, "bat-detect", GPIOD_IN);
                if (IS_ERR(data->gpiod)) {
                        dev_err(dev, "failed to get battery detection GPIO\n");
                        return PTR_ERR(data->gpiod);
                }
                dev_warn(dev, "bat-detect is deprecated, please use battery-detect\n");
        }

        ret = gpiod_get_value_cansleep(data->gpiod);
        if (ret < 0) {
                dev_err(dev, "failed to get gpio state\n");
                return ret;
        }

        data->bat_present = !!ret;
        mutex_init(&data->lock);
        data->dev = dev;
        platform_set_drvdata(pdev, data);

        fgu_cfg.drv_data = data;
        fgu_cfg.fwnode = dev_fwnode(dev);
        data->battery = devm_power_supply_register(dev, &sc27xx_fgu_desc,
                                                   &fgu_cfg);
        if (IS_ERR(data->battery)) {
                dev_err(dev, "failed to register power supply\n");
                return PTR_ERR(data->battery);
        }

        ret = sc27xx_fgu_hw_init(data);
        if (ret) {
                dev_err(dev, "failed to initialize fgu hardware\n");
                return ret;
        }

        ret = devm_add_action_or_reset(dev, sc27xx_fgu_disable, data);
        if (ret) {
                dev_err(dev, "failed to add fgu disable action\n");
                return ret;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        ret = devm_request_threaded_irq(data->dev, irq, NULL,
                                        sc27xx_fgu_interrupt,
                                        IRQF_NO_SUSPEND | IRQF_ONESHOT,
                                        pdev->name, data);
        if (ret) {
                dev_err(data->dev, "failed to request fgu IRQ\n");
                return ret;
        }

        irq = gpiod_to_irq(data->gpiod);
        if (irq < 0) {
                dev_err(dev, "failed to translate GPIO to IRQ\n");
                return irq;
        }

        ret = devm_request_threaded_irq(dev, irq, NULL,
                                        sc27xx_fgu_bat_detection,
                                        IRQF_ONESHOT | IRQF_TRIGGER_RISING |
                                        IRQF_TRIGGER_FALLING,
                                        pdev->name, data);
        if (ret) {
                dev_err(dev, "failed to request IRQ\n");
                return ret;
        }

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int sc27xx_fgu_resume(struct device *dev)
{
        struct sc27xx_fgu_data *data = dev_get_drvdata(dev);
        int ret;

        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,
                                 SC27XX_FGU_LOW_OVERLOAD_INT |
                                 SC27XX_FGU_CLBCNT_DELTA_INT, 0);
        if (ret) {
                dev_err(data->dev, "failed to disable fgu interrupts\n");
                return ret;
        }

        return 0;
}

static int sc27xx_fgu_suspend(struct device *dev)
{
        struct sc27xx_fgu_data *data = dev_get_drvdata(dev);
        int ret, status, ocv;

        ret = sc27xx_fgu_get_status(data, &status);
        if (ret)
                return ret;

        /*
         * If we are charging, then no need to enable the FGU interrupts to
         * adjust the battery capacity.
         */
        if (status != POWER_SUPPLY_STATUS_NOT_CHARGING &&
            status != POWER_SUPPLY_STATUS_DISCHARGING)
                return 0;

        ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,
                                 SC27XX_FGU_LOW_OVERLOAD_INT,
                                 SC27XX_FGU_LOW_OVERLOAD_INT);
        if (ret) {
                dev_err(data->dev, "failed to enable low voltage interrupt\n");
                return ret;
        }

        ret = sc27xx_fgu_get_vbat_ocv(data, &ocv);
        if (ret)
                goto disable_int;

        /*
         * If current OCV is less than the minimum voltage, we should enable the
         * coulomb counter threshold interrupt to notify events to adjust the
         * battery capacity.
         */
        if (ocv < data->min_volt) {
                ret = regmap_update_bits(data->regmap,
                                         data->base + SC27XX_FGU_INT_EN,
                                         SC27XX_FGU_CLBCNT_DELTA_INT,
                                         SC27XX_FGU_CLBCNT_DELTA_INT);
                if (ret) {
                        dev_err(data->dev,
                                "failed to enable coulomb threshold int\n");
                        goto disable_int;
                }
        }

        return 0;

disable_int:
        regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,
                           SC27XX_FGU_LOW_OVERLOAD_INT, 0);
        return ret;
}
#endif

static const struct dev_pm_ops sc27xx_fgu_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(sc27xx_fgu_suspend, sc27xx_fgu_resume)
};

static const struct of_device_id sc27xx_fgu_of_match[] = {
        { .compatible = "sprd,sc2731-fgu", },
        { }
};
MODULE_DEVICE_TABLE(of, sc27xx_fgu_of_match);

static struct platform_driver sc27xx_fgu_driver = {
        .probe = sc27xx_fgu_probe,
        .driver = {
                .name = "sc27xx-fgu",
                .of_match_table = sc27xx_fgu_of_match,
                .pm = &sc27xx_fgu_pm_ops,
        }
};

module_platform_driver(sc27xx_fgu_driver);

MODULE_DESCRIPTION("Spreadtrum SC27XX PMICs Fual Gauge Unit Driver");
MODULE_LICENSE("GPL v2");