/*
 * Driver for Richtek RT9455WSC battery charger.
 *
 * Copyright (C) 2015 Intel Corporation
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/of_irq.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>
#include <linux/power_supply.h>
#include <linux/i2c.h>
#include <linux/acpi.h>
#include <linux/usb/phy.h>
#include <linux/regmap.h>

#define RT9455_MANUFACTURER                     "Richtek"
#define RT9455_MODEL_NAME                       "RT9455"
#define RT9455_DRIVER_NAME                      "rt9455-charger"

#define RT9455_IRQ_NAME                         "interrupt"

#define RT9455_PWR_RDY_DELAY                    1 /* 1 second */
#define RT9455_MAX_CHARGING_TIME                21600 /* 6 hrs */
#define RT9455_BATT_PRESENCE_DELAY              60 /* 60 seconds */

#define RT9455_CHARGE_MODE                      0x00
#define RT9455_BOOST_MODE                       0x01

#define RT9455_FAULT                            0x03

#define RT9455_IAICR_100MA                      0x00
#define RT9455_IAICR_500MA                      0x01
#define RT9455_IAICR_NO_LIMIT                   0x03

#define RT9455_CHARGE_DISABLE                   0x00
#define RT9455_CHARGE_ENABLE                    0x01

#define RT9455_PWR_FAULT                        0x00
#define RT9455_PWR_GOOD                         0x01

#define RT9455_REG_CTRL1                        0x00 /* CTRL1 reg address */
#define RT9455_REG_CTRL2                        0x01 /* CTRL2 reg address */
#define RT9455_REG_CTRL3                        0x02 /* CTRL3 reg address */
#define RT9455_REG_DEV_ID                       0x03 /* DEV_ID reg address */
#define RT9455_REG_CTRL4                        0x04 /* CTRL4 reg address */
#define RT9455_REG_CTRL5                        0x05 /* CTRL5 reg address */
#define RT9455_REG_CTRL6                        0x06 /* CTRL6 reg address */
#define RT9455_REG_CTRL7                        0x07 /* CTRL7 reg address */
#define RT9455_REG_IRQ1                         0x08 /* IRQ1 reg address */
#define RT9455_REG_IRQ2                         0x09 /* IRQ2 reg address */
#define RT9455_REG_IRQ3                         0x0A /* IRQ3 reg address */
#define RT9455_REG_MASK1                        0x0B /* MASK1 reg address */
#define RT9455_REG_MASK2                        0x0C /* MASK2 reg address */
#define RT9455_REG_MASK3                        0x0D /* MASK3 reg address */

enum rt9455_fields {
        F_STAT, F_BOOST, F_PWR_RDY, F_OTG_PIN_POLARITY, /* CTRL1 reg fields */

        F_IAICR, F_TE_SHDN_EN, F_HIGHER_OCP, F_TE, F_IAICR_INT, F_HIZ,
        F_OPA_MODE, /* CTRL2 reg fields */

        F_VOREG, F_OTG_PL, F_OTG_EN, /* CTRL3 reg fields */

        F_VENDOR_ID, F_CHIP_REV, /* DEV_ID reg fields */

        F_RST, /* CTRL4 reg fields */

        F_TMR_EN, F_MIVR, F_IPREC, F_IEOC_PERCENTAGE, /* CTRL5 reg fields*/

        F_IAICR_SEL, F_ICHRG, F_VPREC, /* CTRL6 reg fields */

        F_BATD_EN, F_CHG_EN, F_VMREG, /* CTRL7 reg fields */

        F_TSDI, F_VINOVPI, F_BATAB, /* IRQ1 reg fields */

        F_CHRVPI, F_CHBATOVI, F_CHTERMI, F_CHRCHGI, F_CH32MI, F_CHTREGI,
        F_CHMIVRI, /* IRQ2 reg fields */

        F_BSTBUSOVI, F_BSTOLI, F_BSTLOWVI, F_BST32SI, /* IRQ3 reg fields */

        F_TSDM, F_VINOVPIM, F_BATABM, /* MASK1 reg fields */

        F_CHRVPIM, F_CHBATOVIM, F_CHTERMIM, F_CHRCHGIM, F_CH32MIM, F_CHTREGIM,
        F_CHMIVRIM, /* MASK2 reg fields */

        F_BSTVINOVIM, F_BSTOLIM, F_BSTLOWVIM, F_BST32SIM, /* MASK3 reg fields */

        F_MAX_FIELDS
};

static const struct reg_field rt9455_reg_fields[] = {
        [F_STAT]                = REG_FIELD(RT9455_REG_CTRL1, 4, 5),
        [F_BOOST]               = REG_FIELD(RT9455_REG_CTRL1, 3, 3),
        [F_PWR_RDY]             = REG_FIELD(RT9455_REG_CTRL1, 2, 2),
        [F_OTG_PIN_POLARITY]    = REG_FIELD(RT9455_REG_CTRL1, 1, 1),

        [F_IAICR]               = REG_FIELD(RT9455_REG_CTRL2, 6, 7),
        [F_TE_SHDN_EN]          = REG_FIELD(RT9455_REG_CTRL2, 5, 5),
        [F_HIGHER_OCP]          = REG_FIELD(RT9455_REG_CTRL2, 4, 4),
        [F_TE]                  = REG_FIELD(RT9455_REG_CTRL2, 3, 3),
        [F_IAICR_INT]           = REG_FIELD(RT9455_REG_CTRL2, 2, 2),
        [F_HIZ]                 = REG_FIELD(RT9455_REG_CTRL2, 1, 1),
        [F_OPA_MODE]            = REG_FIELD(RT9455_REG_CTRL2, 0, 0),

        [F_VOREG]               = REG_FIELD(RT9455_REG_CTRL3, 2, 7),
        [F_OTG_PL]              = REG_FIELD(RT9455_REG_CTRL3, 1, 1),
        [F_OTG_EN]              = REG_FIELD(RT9455_REG_CTRL3, 0, 0),

        [F_VENDOR_ID]           = REG_FIELD(RT9455_REG_DEV_ID, 4, 7),
        [F_CHIP_REV]            = REG_FIELD(RT9455_REG_DEV_ID, 0, 3),

        [F_RST]                 = REG_FIELD(RT9455_REG_CTRL4, 7, 7),

        [F_TMR_EN]              = REG_FIELD(RT9455_REG_CTRL5, 7, 7),
        [F_MIVR]                = REG_FIELD(RT9455_REG_CTRL5, 4, 5),
        [F_IPREC]               = REG_FIELD(RT9455_REG_CTRL5, 2, 3),
        [F_IEOC_PERCENTAGE]     = REG_FIELD(RT9455_REG_CTRL5, 0, 1),

        [F_IAICR_SEL]           = REG_FIELD(RT9455_REG_CTRL6, 7, 7),
        [F_ICHRG]               = REG_FIELD(RT9455_REG_CTRL6, 4, 6),
        [F_VPREC]               = REG_FIELD(RT9455_REG_CTRL6, 0, 2),

        [F_BATD_EN]             = REG_FIELD(RT9455_REG_CTRL7, 6, 6),
        [F_CHG_EN]              = REG_FIELD(RT9455_REG_CTRL7, 4, 4),
        [F_VMREG]               = REG_FIELD(RT9455_REG_CTRL7, 0, 3),

        [F_TSDI]                = REG_FIELD(RT9455_REG_IRQ1, 7, 7),
        [F_VINOVPI]             = REG_FIELD(RT9455_REG_IRQ1, 6, 6),
        [F_BATAB]               = REG_FIELD(RT9455_REG_IRQ1, 0, 0),

        [F_CHRVPI]              = REG_FIELD(RT9455_REG_IRQ2, 7, 7),
        [F_CHBATOVI]            = REG_FIELD(RT9455_REG_IRQ2, 5, 5),
        [F_CHTERMI]             = REG_FIELD(RT9455_REG_IRQ2, 4, 4),
        [F_CHRCHGI]             = REG_FIELD(RT9455_REG_IRQ2, 3, 3),
        [F_CH32MI]              = REG_FIELD(RT9455_REG_IRQ2, 2, 2),
        [F_CHTREGI]             = REG_FIELD(RT9455_REG_IRQ2, 1, 1),
        [F_CHMIVRI]             = REG_FIELD(RT9455_REG_IRQ2, 0, 0),

        [F_BSTBUSOVI]           = REG_FIELD(RT9455_REG_IRQ3, 7, 7),
        [F_BSTOLI]              = REG_FIELD(RT9455_REG_IRQ3, 6, 6),
        [F_BSTLOWVI]            = REG_FIELD(RT9455_REG_IRQ3, 5, 5),
        [F_BST32SI]             = REG_FIELD(RT9455_REG_IRQ3, 3, 3),

        [F_TSDM]                = REG_FIELD(RT9455_REG_MASK1, 7, 7),
        [F_VINOVPIM]            = REG_FIELD(RT9455_REG_MASK1, 6, 6),
        [F_BATABM]              = REG_FIELD(RT9455_REG_MASK1, 0, 0),

        [F_CHRVPIM]             = REG_FIELD(RT9455_REG_MASK2, 7, 7),
        [F_CHBATOVIM]           = REG_FIELD(RT9455_REG_MASK2, 5, 5),
        [F_CHTERMIM]            = REG_FIELD(RT9455_REG_MASK2, 4, 4),
        [F_CHRCHGIM]            = REG_FIELD(RT9455_REG_MASK2, 3, 3),
        [F_CH32MIM]             = REG_FIELD(RT9455_REG_MASK2, 2, 2),
        [F_CHTREGIM]            = REG_FIELD(RT9455_REG_MASK2, 1, 1),
        [F_CHMIVRIM]            = REG_FIELD(RT9455_REG_MASK2, 0, 0),

        [F_BSTVINOVIM]          = REG_FIELD(RT9455_REG_MASK3, 7, 7),
        [F_BSTOLIM]             = REG_FIELD(RT9455_REG_MASK3, 6, 6),
        [F_BSTLOWVIM]           = REG_FIELD(RT9455_REG_MASK3, 5, 5),
        [F_BST32SIM]            = REG_FIELD(RT9455_REG_MASK3, 3, 3),
};

#define GET_MASK(fid)   (BIT(rt9455_reg_fields[fid].msb + 1) - \
                         BIT(rt9455_reg_fields[fid].lsb))

/*
 * Each array initialised below shows the possible real-world values for a
 * group of bits belonging to RT9455 registers. The arrays are sorted in
 * ascending order. The index of each real-world value represents the value
 * that is encoded in the group of bits belonging to RT9455 registers.
 */
/* REG06[6:4] (ICHRG) in uAh */
static const int rt9455_ichrg_values[] = {
         500000,  650000,  800000,  950000, 1100000, 1250000, 1400000, 1550000
};

/*
 * When the charger is in charge mode, REG02[7:2] represent battery regulation
 * voltage.
 */
/* REG02[7:2] (VOREG) in uV */
static const int rt9455_voreg_values[] = {
        3500000, 3520000, 3540000, 3560000, 3580000, 3600000, 3620000, 3640000,
        3660000, 3680000, 3700000, 3720000, 3740000, 3760000, 3780000, 3800000,
        3820000, 3840000, 3860000, 3880000, 3900000, 3920000, 3940000, 3960000,
        3980000, 4000000, 4020000, 4040000, 4060000, 4080000, 4100000, 4120000,
        4140000, 4160000, 4180000, 4200000, 4220000, 4240000, 4260000, 4280000,
        4300000, 4330000, 4350000, 4370000, 4390000, 4410000, 4430000, 4450000,
        4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000,
        4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000
};

/*
 * When the charger is in boost mode, REG02[7:2] represent boost output
 * voltage.
 */
/* REG02[7:2] (Boost output voltage) in uV */
static const int rt9455_boost_voltage_values[] = {
        4425000, 4450000, 4475000, 4500000, 4525000, 4550000, 4575000, 4600000,
        4625000, 4650000, 4675000, 4700000, 4725000, 4750000, 4775000, 4800000,
        4825000, 4850000, 4875000, 4900000, 4925000, 4950000, 4975000, 5000000,
        5025000, 5050000, 5075000, 5100000, 5125000, 5150000, 5175000, 5200000,
        5225000, 5250000, 5275000, 5300000, 5325000, 5350000, 5375000, 5400000,
        5425000, 5450000, 5475000, 5500000, 5525000, 5550000, 5575000, 5600000,
        5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000,
        5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000,
};

/* REG07[3:0] (VMREG) in uV */
static const int rt9455_vmreg_values[] = {
        4200000, 4220000, 4240000, 4260000, 4280000, 4300000, 4320000, 4340000,
        4360000, 4380000, 4400000, 4430000, 4450000, 4450000, 4450000, 4450000
};

/* REG05[5:4] (IEOC_PERCENTAGE) */
static const int rt9455_ieoc_percentage_values[] = {
        10, 30, 20, 30
};

/* REG05[1:0] (MIVR) in uV */
static const int rt9455_mivr_values[] = {
        4000000, 4250000, 4500000, 5000000
};

/* REG05[1:0] (IAICR) in uA */
static const int rt9455_iaicr_values[] = {
        100000, 500000, 1000000, 2000000
};

struct rt9455_info {
        struct i2c_client               *client;
        struct regmap                   *regmap;
        struct regmap_field             *regmap_fields[F_MAX_FIELDS];
        struct power_supply             *charger;
#if IS_ENABLED(CONFIG_USB_PHY)
        struct usb_phy                  *usb_phy;
        struct notifier_block           nb;
#endif
        struct delayed_work             pwr_rdy_work;
        struct delayed_work             max_charging_time_work;
        struct delayed_work             batt_presence_work;
        u32                             voreg;
        u32                             boost_voltage;
};

/*
 * Iterate through each element of the 'tbl' array until an element whose value
 * is greater than v is found. Return the index of the respective element,
 * or the index of the last element in the array, if no such element is found.
 */
static unsigned int rt9455_find_idx(const int tbl[], int tbl_size, int v)
{
        int i;

        /*
         * No need to iterate until the last index in the table because
         * if no element greater than v is found in the table,
         * or if only the last element is greater than v,
         * function returns the index of the last element.
         */
        for (i = 0; i < tbl_size - 1; i++)
                if (v <= tbl[i])
                        return i;

        return (tbl_size - 1);
}

static int rt9455_get_field_val(struct rt9455_info *info,
                                enum rt9455_fields field,
                                const int tbl[], int tbl_size, int *val)
{
        unsigned int v;
        int ret;

        ret = regmap_field_read(info->regmap_fields[field], &v);
        if (ret)
                return ret;

        v = (v >= tbl_size) ? (tbl_size - 1) : v;
        *val = tbl[v];

        return 0;
}

static int rt9455_set_field_val(struct rt9455_info *info,
                                enum rt9455_fields field,
                                const int tbl[], int tbl_size, int val)
{
        unsigned int idx = rt9455_find_idx(tbl, tbl_size, val);

        return regmap_field_write(info->regmap_fields[field], idx);
}

static int rt9455_register_reset(struct rt9455_info *info)
{
        struct device *dev = &info->client->dev;
        unsigned int v;
        int ret, limit = 100;

        ret = regmap_field_write(info->regmap_fields[F_RST], 0x01);
        if (ret) {
                dev_err(dev, "Failed to set RST bit\n");
                return ret;
        }

        /*
         * To make sure that reset operation has finished, loop until RST bit
         * is set to 0.
         */
        do {
                ret = regmap_field_read(info->regmap_fields[F_RST], &v);
                if (ret) {
                        dev_err(dev, "Failed to read RST bit\n");
                        return ret;
                }

                if (!v)
                        break;

                usleep_range(10, 100);
        } while (--limit);

        if (!limit)
                return -EIO;

        return 0;
}

/* Charger power supply property routines */
static enum power_supply_property rt9455_charger_properties[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_HEALTH,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
        POWER_SUPPLY_PROP_SCOPE,
        POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
};

static char *rt9455_charger_supplied_to[] = {
        "main-battery",
};

static int rt9455_charger_get_status(struct rt9455_info *info,
                                     union power_supply_propval *val)
{
        unsigned int v, pwr_rdy;
        int ret;

        ret = regmap_field_read(info->regmap_fields[F_PWR_RDY],
                                &pwr_rdy);
        if (ret) {
                dev_err(&info->client->dev, "Failed to read PWR_RDY bit\n");
                return ret;
        }

        /*
         * If PWR_RDY bit is unset, the battery is discharging. Otherwise,
         * STAT bits value must be checked.
         */
        if (!pwr_rdy) {
                val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
                return 0;
        }

        ret = regmap_field_read(info->regmap_fields[F_STAT], &v);
        if (ret) {
                dev_err(&info->client->dev, "Failed to read STAT bits\n");
                return ret;
        }

        switch (v) {
        case 0:
                /*
                 * If PWR_RDY bit is set, but STAT bits value is 0, the charger
                 * may be in one of the following cases:
                 * 1. CHG_EN bit is 0.
                 * 2. CHG_EN bit is 1 but the battery is not connected.
                 * In any of these cases, POWER_SUPPLY_STATUS_NOT_CHARGING is
                 * returned.
                 */
                val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                return 0;
        case 1:
                val->intval = POWER_SUPPLY_STATUS_CHARGING;
                return 0;
        case 2:
                val->intval = POWER_SUPPLY_STATUS_FULL;
                return 0;
        default:
                val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
                return 0;
        }
}

static int rt9455_charger_get_health(struct rt9455_info *info,
                                     union power_supply_propval *val)
{
        struct device *dev = &info->client->dev;
        unsigned int v;
        int ret;

        val->intval = POWER_SUPPLY_HEALTH_GOOD;

        ret = regmap_read(info->regmap, RT9455_REG_IRQ1, &v);
        if (ret) {
                dev_err(dev, "Failed to read IRQ1 register\n");
                return ret;
        }

        if (v & GET_MASK(F_TSDI)) {
                val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
                return 0;
        }
        if (v & GET_MASK(F_VINOVPI)) {
                val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
                return 0;
        }
        if (v & GET_MASK(F_BATAB)) {
                val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
                return 0;
        }

        ret = regmap_read(info->regmap, RT9455_REG_IRQ2, &v);
        if (ret) {
                dev_err(dev, "Failed to read IRQ2 register\n");
                return ret;
        }

        if (v & GET_MASK(F_CHBATOVI)) {
                val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
                return 0;
        }
        if (v & GET_MASK(F_CH32MI)) {
                val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
                return 0;
        }

        ret = regmap_read(info->regmap, RT9455_REG_IRQ3, &v);
        if (ret) {
                dev_err(dev, "Failed to read IRQ3 register\n");
                return ret;
        }

        if (v & GET_MASK(F_BSTBUSOVI)) {
                val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
                return 0;
        }
        if (v & GET_MASK(F_BSTOLI)) {
                val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
                return 0;
        }
        if (v & GET_MASK(F_BSTLOWVI)) {
                val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
                return 0;
        }
        if (v & GET_MASK(F_BST32SI)) {
                val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
                return 0;
        }

        ret = regmap_field_read(info->regmap_fields[F_STAT], &v);
        if (ret) {
                dev_err(dev, "Failed to read STAT bits\n");
                return ret;
        }

        if (v == RT9455_FAULT) {
                val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
                return 0;
        }

        return 0;
}

static int rt9455_charger_get_battery_presence(struct rt9455_info *info,
                                               union power_supply_propval *val)
{
        unsigned int v;
        int ret;

        ret = regmap_field_read(info->regmap_fields[F_BATAB], &v);
        if (ret) {
                dev_err(&info->client->dev, "Failed to read BATAB bit\n");
                return ret;
        }

        /*
         * Since BATAB is 1 when battery is NOT present and 0 otherwise,
         * !BATAB is returned.
         */
        val->intval = !v;

        return 0;
}

static int rt9455_charger_get_online(struct rt9455_info *info,
                                     union power_supply_propval *val)
{
        unsigned int v;
        int ret;

        ret = regmap_field_read(info->regmap_fields[F_PWR_RDY], &v);
        if (ret) {
                dev_err(&info->client->dev, "Failed to read PWR_RDY bit\n");
                return ret;
        }

        val->intval = (int)v;

        return 0;
}

static int rt9455_charger_get_current(struct rt9455_info *info,
                                      union power_supply_propval *val)
{
        int curr;
        int ret;

        ret = rt9455_get_field_val(info, F_ICHRG,
                                   rt9455_ichrg_values,
                                   ARRAY_SIZE(rt9455_ichrg_values),
                                   &curr);
        if (ret) {
                dev_err(&info->client->dev, "Failed to read ICHRG value\n");
                return ret;
        }

        val->intval = curr;

        return 0;
}

static int rt9455_charger_get_current_max(struct rt9455_info *info,
                                          union power_supply_propval *val)
{
        int idx = ARRAY_SIZE(rt9455_ichrg_values) - 1;

        val->intval = rt9455_ichrg_values[idx];

        return 0;
}

static int rt9455_charger_get_voltage(struct rt9455_info *info,
                                      union power_supply_propval *val)
{
        int voltage;
        int ret;

        ret = rt9455_get_field_val(info, F_VOREG,
                                   rt9455_voreg_values,
                                   ARRAY_SIZE(rt9455_voreg_values),
                                   &voltage);
        if (ret) {
                dev_err(&info->client->dev, "Failed to read VOREG value\n");
                return ret;
        }

        val->intval = voltage;

        return 0;
}

static int rt9455_charger_get_voltage_max(struct rt9455_info *info,
                                          union power_supply_propval *val)
{
        int idx = ARRAY_SIZE(rt9455_vmreg_values) - 1;

        val->intval = rt9455_vmreg_values[idx];

        return 0;
}

static int rt9455_charger_get_term_current(struct rt9455_info *info,
                                           union power_supply_propval *val)
{
        struct device *dev = &info->client->dev;
        int ichrg, ieoc_percentage, ret;

        ret = rt9455_get_field_val(info, F_ICHRG,
                                   rt9455_ichrg_values,
                                   ARRAY_SIZE(rt9455_ichrg_values),
                                   &ichrg);
        if (ret) {
                dev_err(dev, "Failed to read ICHRG value\n");
                return ret;
        }

        ret = rt9455_get_field_val(info, F_IEOC_PERCENTAGE,
                                   rt9455_ieoc_percentage_values,
                                   ARRAY_SIZE(rt9455_ieoc_percentage_values),
                                   &ieoc_percentage);
        if (ret) {
                dev_err(dev, "Failed to read IEOC value\n");
                return ret;
        }

        val->intval = ichrg * ieoc_percentage / 100;

        return 0;
}

static int rt9455_charger_get_property(struct power_supply *psy,
                                       enum power_supply_property psp,
                                       union power_supply_propval *val)
{
        struct rt9455_info *info = power_supply_get_drvdata(psy);

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                return rt9455_charger_get_status(info, val);
        case POWER_SUPPLY_PROP_HEALTH:
                return rt9455_charger_get_health(info, val);
        case POWER_SUPPLY_PROP_PRESENT:
                return rt9455_charger_get_battery_presence(info, val);
        case POWER_SUPPLY_PROP_ONLINE:
                return rt9455_charger_get_online(info, val);
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
                return rt9455_charger_get_current(info, val);
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
                return rt9455_charger_get_current_max(info, val);
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                return rt9455_charger_get_voltage(info, val);
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
                return rt9455_charger_get_voltage_max(info, val);
        case POWER_SUPPLY_PROP_SCOPE:
                val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
                return 0;
        case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
                return rt9455_charger_get_term_current(info, val);
        case POWER_SUPPLY_PROP_MODEL_NAME:
                val->strval = RT9455_MODEL_NAME;
                return 0;
        case POWER_SUPPLY_PROP_MANUFACTURER:
                val->strval = RT9455_MANUFACTURER;
                return 0;
        default:
                return -ENODATA;
        }
}

static int rt9455_hw_init(struct rt9455_info *info, u32 ichrg,
                          u32 ieoc_percentage,
                          u32 mivr, u32 iaicr)
{
        struct device *dev = &info->client->dev;
        int idx, ret;

        ret = rt9455_register_reset(info);
        if (ret) {
                dev_err(dev, "Power On Reset failed\n");
                return ret;
        }

        /* Set TE bit in order to enable end of charge detection */
        ret = regmap_field_write(info->regmap_fields[F_TE], 1);
        if (ret) {
                dev_err(dev, "Failed to set TE bit\n");
                return ret;
        }

        /* Set TE_SHDN_EN bit in order to enable end of charge detection */
        ret = regmap_field_write(info->regmap_fields[F_TE_SHDN_EN], 1);
        if (ret) {
                dev_err(dev, "Failed to set TE_SHDN_EN bit\n");
                return ret;
        }

        /*
         * Set BATD_EN bit in order to enable battery detection
         * when charging is done
         */
        ret = regmap_field_write(info->regmap_fields[F_BATD_EN], 1);
        if (ret) {
                dev_err(dev, "Failed to set BATD_EN bit\n");
                return ret;
        }

        /*
         * Disable Safety Timer. In charge mode, this timer terminates charging
         * if no read or write via I2C is done within 32 minutes. This timer
         * avoids overcharging the baterry when the OS is not loaded and the
         * charger is connected to a power source.
         * In boost mode, this timer triggers BST32SI interrupt if no read or
         * write via I2C is done within 32 seconds.
         * When the OS is loaded and the charger driver is inserted, it is used
         * delayed_work, named max_charging_time_work, to avoid overcharging
         * the battery.
         */
        ret = regmap_field_write(info->regmap_fields[F_TMR_EN], 0x00);
        if (ret) {
                dev_err(dev, "Failed to disable Safety Timer\n");
                return ret;
        }

        /* Set ICHRG to value retrieved from device-specific data */
        ret = rt9455_set_field_val(info, F_ICHRG,
                                   rt9455_ichrg_values,
                                   ARRAY_SIZE(rt9455_ichrg_values), ichrg);
        if (ret) {
                dev_err(dev, "Failed to set ICHRG value\n");
                return ret;
        }

        /* Set IEOC Percentage to value retrieved from device-specific data */
        ret = rt9455_set_field_val(info, F_IEOC_PERCENTAGE,
                                   rt9455_ieoc_percentage_values,
                                   ARRAY_SIZE(rt9455_ieoc_percentage_values),
                                   ieoc_percentage);
        if (ret) {
                dev_err(dev, "Failed to set IEOC Percentage value\n");
                return ret;
        }

        /* Set VOREG to value retrieved from device-specific data */
        ret = rt9455_set_field_val(info, F_VOREG,
                                   rt9455_voreg_values,
                                   ARRAY_SIZE(rt9455_voreg_values),
                                   info->voreg);
        if (ret) {
                dev_err(dev, "Failed to set VOREG value\n");
                return ret;
        }

        /* Set VMREG value to maximum (4.45V). */
        idx = ARRAY_SIZE(rt9455_vmreg_values) - 1;
        ret = rt9455_set_field_val(info, F_VMREG,
                                   rt9455_vmreg_values,
                                   ARRAY_SIZE(rt9455_vmreg_values),
                                   rt9455_vmreg_values[idx]);
        if (ret) {
                dev_err(dev, "Failed to set VMREG value\n");
                return ret;
        }

        /*
         * Set MIVR to value retrieved from device-specific data.
         * If no value is specified, default value for MIVR is 4.5V.
         */
        if (mivr == -1)
                mivr = 4500000;

        ret = rt9455_set_field_val(info, F_MIVR,
                                   rt9455_mivr_values,
                                   ARRAY_SIZE(rt9455_mivr_values), mivr);
        if (ret) {
                dev_err(dev, "Failed to set MIVR value\n");
                return ret;
        }

        /*
         * Set IAICR to value retrieved from device-specific data.
         * If no value is specified, default value for IAICR is 500 mA.
         */
        if (iaicr == -1)
                iaicr = 500000;

        ret = rt9455_set_field_val(info, F_IAICR,
                                   rt9455_iaicr_values,
                                   ARRAY_SIZE(rt9455_iaicr_values), iaicr);
        if (ret) {
                dev_err(dev, "Failed to set IAICR value\n");
                return ret;
        }

        /*
         * Set IAICR_INT bit so that IAICR value is determined by IAICR bits
         * and not by OTG pin.
         */
        ret = regmap_field_write(info->regmap_fields[F_IAICR_INT], 0x01);
        if (ret) {
                dev_err(dev, "Failed to set IAICR_INT bit\n");
                return ret;
        }

        /*
         * Disable CHMIVRI interrupt. Because the driver sets MIVR value,
         * CHMIVRI is triggered, but there is no action to be taken by the
         * driver when CHMIVRI is triggered.
         */
        ret = regmap_field_write(info->regmap_fields[F_CHMIVRIM], 0x01);
        if (ret) {
                dev_err(dev, "Failed to mask CHMIVRI interrupt\n");
                return ret;
        }

        return 0;
}

#if IS_ENABLED(CONFIG_USB_PHY)
/*
 * Before setting the charger into boost mode, boost output voltage is
 * set. This is needed because boost output voltage may differ from battery
 * regulation voltage. F_VOREG bits represent either battery regulation voltage
 * or boost output voltage, depending on the mode the charger is. Both battery
 * regulation voltage and boost output voltage are read from DT/ACPI during
 * probe.
 */
static int rt9455_set_boost_voltage_before_boost_mode(struct rt9455_info *info)
{
        struct device *dev = &info->client->dev;
        int ret;

        ret = rt9455_set_field_val(info, F_VOREG,
                                   rt9455_boost_voltage_values,
                                   ARRAY_SIZE(rt9455_boost_voltage_values),
                                   info->boost_voltage);
        if (ret) {
                dev_err(dev, "Failed to set boost output voltage value\n");
                return ret;
        }

        return 0;
}
#endif

/*
 * Before setting the charger into charge mode, battery regulation voltage is
 * set. This is needed because boost output voltage may differ from battery
 * regulation voltage. F_VOREG bits represent either battery regulation voltage
 * or boost output voltage, depending on the mode the charger is. Both battery
 * regulation voltage and boost output voltage are read from DT/ACPI during
 * probe.
 */
static int rt9455_set_voreg_before_charge_mode(struct rt9455_info *info)
{
        struct device *dev = &info->client->dev;
        int ret;

        ret = rt9455_set_field_val(info, F_VOREG,
                                   rt9455_voreg_values,
                                   ARRAY_SIZE(rt9455_voreg_values),
                                   info->voreg);
        if (ret) {
                dev_err(dev, "Failed to set VOREG value\n");
                return ret;
        }

        return 0;
}

static int rt9455_irq_handler_check_irq1_register(struct rt9455_info *info,
                                                  bool *_is_battery_absent,
                                                  bool *_alert_userspace)
{
        unsigned int irq1, mask1, mask2;
        struct device *dev = &info->client->dev;
        bool is_battery_absent = false;
        bool alert_userspace = false;
        int ret;

        ret = regmap_read(info->regmap, RT9455_REG_IRQ1, &irq1);
        if (ret) {
                dev_err(dev, "Failed to read IRQ1 register\n");
                return ret;
        }

        ret = regmap_read(info->regmap, RT9455_REG_MASK1, &mask1);
        if (ret) {
                dev_err(dev, "Failed to read MASK1 register\n");
                return ret;
        }

        if (irq1 & GET_MASK(F_TSDI)) {
                dev_err(dev, "Thermal shutdown fault occurred\n");
                alert_userspace = true;
        }

        if (irq1 & GET_MASK(F_VINOVPI)) {
                dev_err(dev, "Overvoltage input occurred\n");
                alert_userspace = true;
        }

        if (irq1 & GET_MASK(F_BATAB)) {
                dev_err(dev, "Battery absence occurred\n");
                is_battery_absent = true;
                alert_userspace = true;

                if ((mask1 & GET_MASK(F_BATABM)) == 0) {
                        ret = regmap_field_write(info->regmap_fields[F_BATABM],
                                                 0x01);
                        if (ret) {
                                dev_err(dev, "Failed to mask BATAB interrupt\n");
                                return ret;
                        }
                }

                ret = regmap_read(info->regmap, RT9455_REG_MASK2, &mask2);
                if (ret) {
                        dev_err(dev, "Failed to read MASK2 register\n");
                        return ret;
                }

                if (mask2 & GET_MASK(F_CHTERMIM)) {
                        ret = regmap_field_write(
                                info->regmap_fields[F_CHTERMIM], 0x00);
                        if (ret) {
                                dev_err(dev, "Failed to unmask CHTERMI interrupt\n");
                                return ret;
                        }
                }

                if (mask2 & GET_MASK(F_CHRCHGIM)) {
                        ret = regmap_field_write(
                                info->regmap_fields[F_CHRCHGIM], 0x00);
                        if (ret) {
                                dev_err(dev, "Failed to unmask CHRCHGI interrupt\n");
                                return ret;
                        }
                }

                /*
                 * When the battery is absent, max_charging_time_work is
                 * cancelled, since no charging is done.
                 */
                cancel_delayed_work_sync(&info->max_charging_time_work);
                /*
                 * Since no interrupt is triggered when the battery is
                 * reconnected, max_charging_time_work is not rescheduled.
                 * Therefore, batt_presence_work is scheduled to check whether
                 * the battery is still absent or not.
                 */
                queue_delayed_work(system_power_efficient_wq,
                                   &info->batt_presence_work,
                                   RT9455_BATT_PRESENCE_DELAY * HZ);
        }

        *_is_battery_absent = is_battery_absent;

        if (alert_userspace)
                *_alert_userspace = alert_userspace;

        return 0;
}

static int rt9455_irq_handler_check_irq2_register(struct rt9455_info *info,
                                                  bool is_battery_absent,
                                                  bool *_alert_userspace)
{
        unsigned int irq2, mask2;
        struct device *dev = &info->client->dev;
        bool alert_userspace = false;
        int ret;

        ret = regmap_read(info->regmap, RT9455_REG_IRQ2, &irq2);
        if (ret) {
                dev_err(dev, "Failed to read IRQ2 register\n");
                return ret;
        }

        ret = regmap_read(info->regmap, RT9455_REG_MASK2, &mask2);
        if (ret) {
                dev_err(dev, "Failed to read MASK2 register\n");
                return ret;
        }

        if (irq2 & GET_MASK(F_CHRVPI)) {
                dev_dbg(dev, "Charger fault occurred\n");
                /*
                 * CHRVPI bit is set in 2 cases:
                 * 1. when the power source is connected to the charger.
                 * 2. when the power source is disconnected from the charger.
                 * To identify the case, PWR_RDY bit is checked. Because
                 * PWR_RDY bit is set / cleared after CHRVPI interrupt is
                 * triggered, it is used delayed_work to later read PWR_RDY bit.
                 * Also, do not set to true alert_userspace, because there is no
                 * need to notify userspace when CHRVPI interrupt has occurred.
                 * Userspace will be notified after PWR_RDY bit is read.
                 */
                queue_delayed_work(system_power_efficient_wq,
                                   &info->pwr_rdy_work,
                                   RT9455_PWR_RDY_DELAY * HZ);
        }
        if (irq2 & GET_MASK(F_CHBATOVI)) {
                dev_err(dev, "Battery OVP occurred\n");
                alert_userspace = true;
        }
        if (irq2 & GET_MASK(F_CHTERMI)) {
                dev_dbg(dev, "Charge terminated\n");
                if (!is_battery_absent) {
                        if ((mask2 & GET_MASK(F_CHTERMIM)) == 0) {
                                ret = regmap_field_write(
                                        info->regmap_fields[F_CHTERMIM], 0x01);

                                if (ret) {
                                        dev_err(dev, "Failed to mask CHTERMI interrupt\n");
                                        return ret;
                                }
                                /*
                                 * Update MASK2 value, since CHTERMIM bit is
                                 * set.
                                 */
                                mask2 = mask2 | GET_MASK(F_CHTERMIM);
                        }
                        cancel_delayed_work_sync(&info->max_charging_time_work);
                        alert_userspace = true;
                }
        }
        if (irq2 & GET_MASK(F_CHRCHGI)) {
                dev_dbg(dev, "Recharge request\n");
                ret = regmap_field_write(info->regmap_fields[F_CHG_EN],
                                         RT9455_CHARGE_ENABLE);
                if (ret) {
                        dev_err(dev, "Failed to enable charging\n");
                        return ret;
                }
                if (mask2 & GET_MASK(F_CHTERMIM)) {
                        ret = regmap_field_write(
                                info->regmap_fields[F_CHTERMIM], 0x00);
                        if (ret) {
                                dev_err(dev, "Failed to unmask CHTERMI interrupt\n");
                                return ret;
                        }
                        /* Update MASK2 value, since CHTERMIM bit is cleared. */
                        mask2 = mask2 & ~GET_MASK(F_CHTERMIM);
                }
                if (!is_battery_absent) {
                        /*
                         * No need to check whether the charger is connected to
                         * power source when CHRCHGI is received, since CHRCHGI
                         * is not triggered if the charger is not connected to
                         * the power source.
                         */
                        queue_delayed_work(system_power_efficient_wq,
                                           &info->max_charging_time_work,
                                           RT9455_MAX_CHARGING_TIME * HZ);
                        alert_userspace = true;
                }
        }
        if (irq2 & GET_MASK(F_CH32MI)) {
                dev_err(dev, "Charger fault. 32 mins timeout occurred\n");
                alert_userspace = true;
        }
        if (irq2 & GET_MASK(F_CHTREGI)) {
                dev_warn(dev,
                         "Charger warning. Thermal regulation loop active\n");
                alert_userspace = true;
        }
        if (irq2 & GET_MASK(F_CHMIVRI)) {
                dev_dbg(dev,
                        "Charger warning. Input voltage MIVR loop active\n");
        }

        if (alert_userspace)
                *_alert_userspace = alert_userspace;

        return 0;
}

static int rt9455_irq_handler_check_irq3_register(struct rt9455_info *info,
                                                  bool *_alert_userspace)
{
        unsigned int irq3, mask3;
        struct device *dev = &info->client->dev;
        bool alert_userspace = false;
        int ret;

        ret = regmap_read(info->regmap, RT9455_REG_IRQ3, &irq3);
        if (ret) {
                dev_err(dev, "Failed to read IRQ3 register\n");
                return ret;
        }

        ret = regmap_read(info->regmap, RT9455_REG_MASK3, &mask3);
        if (ret) {
                dev_err(dev, "Failed to read MASK3 register\n");
                return ret;
        }

        if (irq3 & GET_MASK(F_BSTBUSOVI)) {
                dev_err(dev, "Boost fault. Overvoltage input occurred\n");
                alert_userspace = true;
        }
        if (irq3 & GET_MASK(F_BSTOLI)) {
                dev_err(dev, "Boost fault. Overload\n");
                alert_userspace = true;
        }
        if (irq3 & GET_MASK(F_BSTLOWVI)) {
                dev_err(dev, "Boost fault. Battery voltage too low\n");
                alert_userspace = true;
        }
        if (irq3 & GET_MASK(F_BST32SI)) {
                dev_err(dev, "Boost fault. 32 seconds timeout occurred.\n");
                alert_userspace = true;
        }

        if (alert_userspace) {
                dev_info(dev, "Boost fault occurred, therefore the charger goes into charge mode\n");
                ret = rt9455_set_voreg_before_charge_mode(info);
                if (ret) {
                        dev_err(dev, "Failed to set VOREG before entering charge mode\n");
                        return ret;
                }
                ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
                                         RT9455_CHARGE_MODE);
                if (ret) {
                        dev_err(dev, "Failed to set charger in charge mode\n");
                        return ret;
                }
                *_alert_userspace = alert_userspace;
        }

        return 0;
}

static irqreturn_t rt9455_irq_handler_thread(int irq, void *data)
{
        struct rt9455_info *info = data;
        struct device *dev;
        bool alert_userspace = false;
        bool is_battery_absent = false;
        unsigned int status;
        int ret;

        if (!info)
                return IRQ_NONE;

        dev = &info->client->dev;

        if (irq != info->client->irq) {
                dev_err(dev, "Interrupt is not for RT9455 charger\n");
                return IRQ_NONE;
        }

        ret = regmap_field_read(info->regmap_fields[F_STAT], &status);
        if (ret) {
                dev_err(dev, "Failed to read STAT bits\n");
                return IRQ_HANDLED;
        }
        dev_dbg(dev, "Charger status is %d\n", status);

        /*
         * Each function that processes an IRQ register receives as output
         * parameter alert_userspace pointer. alert_userspace is set to true
         * in such a function only if an interrupt has occurred in the
         * respective interrupt register. This way, it is avoided the following
         * case: interrupt occurs only in IRQ1 register,
         * rt9455_irq_handler_check_irq1_register() function sets to true
         * alert_userspace, but rt9455_irq_handler_check_irq2_register()
         * and rt9455_irq_handler_check_irq3_register() functions set to false
         * alert_userspace and power_supply_changed() is never called.
         */
        ret = rt9455_irq_handler_check_irq1_register(info, &is_battery_absent,
                                                     &alert_userspace);
        if (ret) {
                dev_err(dev, "Failed to handle IRQ1 register\n");
                return IRQ_HANDLED;
        }

        ret = rt9455_irq_handler_check_irq2_register(info, is_battery_absent,
                                                     &alert_userspace);
        if (ret) {
                dev_err(dev, "Failed to handle IRQ2 register\n");
                return IRQ_HANDLED;
        }

        ret = rt9455_irq_handler_check_irq3_register(info, &alert_userspace);
        if (ret) {
                dev_err(dev, "Failed to handle IRQ3 register\n");
                return IRQ_HANDLED;
        }

        if (alert_userspace) {
                /*
                 * Sometimes, an interrupt occurs while rt9455_probe() function
                 * is executing and power_supply_register() is not yet called.
                 * Do not call power_supply_changed() in this case.
                 */
                if (info->charger)
                        power_supply_changed(info->charger);
        }

        return IRQ_HANDLED;
}

static int rt9455_discover_charger(struct rt9455_info *info, u32 *ichrg,
                                   u32 *ieoc_percentage,
                                   u32 *mivr, u32 *iaicr)
{
        struct device *dev = &info->client->dev;
        int ret;

        if (!dev->of_node && !ACPI_HANDLE(dev)) {
                dev_err(dev, "No support for either device tree or ACPI\n");
                return -EINVAL;
        }
        /*
         * ICHRG, IEOC_PERCENTAGE, VOREG and boost output voltage are mandatory
         * parameters.
         */
        ret = device_property_read_u32(dev, "richtek,output-charge-current",
                                       ichrg);
        if (ret) {
                dev_err(dev, "Error: missing \"output-charge-current\" property\n");
                return ret;
        }

        ret = device_property_read_u32(dev, "richtek,end-of-charge-percentage",
                                       ieoc_percentage);
        if (ret) {
                dev_err(dev, "Error: missing \"end-of-charge-percentage\" property\n");
                return ret;
        }

        ret = device_property_read_u32(dev,
                                       "richtek,battery-regulation-voltage",
                                       &info->voreg);
        if (ret) {
                dev_err(dev, "Error: missing \"battery-regulation-voltage\" property\n");
                return ret;
        }

        ret = device_property_read_u32(dev, "richtek,boost-output-voltage",
                                       &info->boost_voltage);
        if (ret) {
                dev_err(dev, "Error: missing \"boost-output-voltage\" property\n");
                return ret;
        }

        /*
         * MIVR and IAICR are optional parameters. Do not return error if one of
         * them is not present in ACPI table or device tree specification.
         */
        device_property_read_u32(dev, "richtek,min-input-voltage-regulation",
                                 mivr);
        device_property_read_u32(dev, "richtek,avg-input-current-regulation",
                                 iaicr);

        return 0;
}

#if IS_ENABLED(CONFIG_USB_PHY)
static int rt9455_usb_event_none(struct rt9455_info *info,
                                 u8 opa_mode, u8 iaicr)
{
        struct device *dev = &info->client->dev;
        int ret;

        if (opa_mode == RT9455_BOOST_MODE) {
                ret = rt9455_set_voreg_before_charge_mode(info);
                if (ret) {
                        dev_err(dev, "Failed to set VOREG before entering charge mode\n");
                        return ret;
                }
                /*
                 * If the charger is in boost mode, and it has received
                 * USB_EVENT_NONE, this means the consumer device powered by the
                 * charger is not connected anymore.
                 * In this case, the charger goes into charge mode.
                 */
                dev_dbg(dev, "USB_EVENT_NONE received, therefore the charger goes into charge mode\n");
                ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
                                         RT9455_CHARGE_MODE);
                if (ret) {
                        dev_err(dev, "Failed to set charger in charge mode\n");
                        return NOTIFY_DONE;
                }
        }

        dev_dbg(dev, "USB_EVENT_NONE received, therefore IAICR is set to its minimum value\n");
        if (iaicr != RT9455_IAICR_100MA) {
                ret = regmap_field_write(info->regmap_fields[F_IAICR],
                                         RT9455_IAICR_100MA);
                if (ret) {
                        dev_err(dev, "Failed to set IAICR value\n");
                        return NOTIFY_DONE;
                }
        }

        return NOTIFY_OK;
}

static int rt9455_usb_event_vbus(struct rt9455_info *info,
                                 u8 opa_mode, u8 iaicr)
{
        struct device *dev = &info->client->dev;
        int ret;

        if (opa_mode == RT9455_BOOST_MODE) {
                ret = rt9455_set_voreg_before_charge_mode(info);
                if (ret) {
                        dev_err(dev, "Failed to set VOREG before entering charge mode\n");
                        return ret;
                }
                /*
                 * If the charger is in boost mode, and it has received
                 * USB_EVENT_VBUS, this means the consumer device powered by the
                 * charger is not connected anymore.
                 * In this case, the charger goes into charge mode.
                 */
                dev_dbg(dev, "USB_EVENT_VBUS received, therefore the charger goes into charge mode\n");
                ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
                                         RT9455_CHARGE_MODE);
                if (ret) {
                        dev_err(dev, "Failed to set charger in charge mode\n");
                        return NOTIFY_DONE;
                }
        }

        dev_dbg(dev, "USB_EVENT_VBUS received, therefore IAICR is set to 500 mA\n");
        if (iaicr != RT9455_IAICR_500MA) {
                ret = regmap_field_write(info->regmap_fields[F_IAICR],
                                         RT9455_IAICR_500MA);
                if (ret) {
                        dev_err(dev, "Failed to set IAICR value\n");
                        return NOTIFY_DONE;
                }
        }

        return NOTIFY_OK;
}

static int rt9455_usb_event_id(struct rt9455_info *info,
                               u8 opa_mode, u8 iaicr)
{
        struct device *dev = &info->client->dev;
        int ret;

        if (opa_mode == RT9455_CHARGE_MODE) {
                ret = rt9455_set_boost_voltage_before_boost_mode(info);
                if (ret) {
                        dev_err(dev, "Failed to set boost output voltage before entering boost mode\n");
                        return ret;
                }
                /*
                 * If the charger is in charge mode, and it has received
                 * USB_EVENT_ID, this means a consumer device is connected and
                 * it should be powered by the charger.
                 * In this case, the charger goes into boost mode.
                 */
                dev_dbg(dev, "USB_EVENT_ID received, therefore the charger goes into boost mode\n");
                ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
                                         RT9455_BOOST_MODE);
                if (ret) {
                        dev_err(dev, "Failed to set charger in boost mode\n");
                        return NOTIFY_DONE;
                }
        }

        dev_dbg(dev, "USB_EVENT_ID received, therefore IAICR is set to its minimum value\n");
        if (iaicr != RT9455_IAICR_100MA) {
                ret = regmap_field_write(info->regmap_fields[F_IAICR],
                                         RT9455_IAICR_100MA);
                if (ret) {
                        dev_err(dev, "Failed to set IAICR value\n");
                        return NOTIFY_DONE;
                }
        }

        return NOTIFY_OK;
}

static int rt9455_usb_event_charger(struct rt9455_info *info,
                                    u8 opa_mode, u8 iaicr)
{
        struct device *dev = &info->client->dev;
        int ret;

        if (opa_mode == RT9455_BOOST_MODE) {
                ret = rt9455_set_voreg_before_charge_mode(info);
                if (ret) {
                        dev_err(dev, "Failed to set VOREG before entering charge mode\n");
                        return ret;
                }
                /*
                 * If the charger is in boost mode, and it has received
                 * USB_EVENT_CHARGER, this means the consumer device powered by
                 * the charger is not connected anymore.
                 * In this case, the charger goes into charge mode.
                 */
                dev_dbg(dev, "USB_EVENT_CHARGER received, therefore the charger goes into charge mode\n");
                ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
                                         RT9455_CHARGE_MODE);
                if (ret) {
                        dev_err(dev, "Failed to set charger in charge mode\n");
                        return NOTIFY_DONE;
                }
        }

        dev_dbg(dev, "USB_EVENT_CHARGER received, therefore IAICR is set to no current limit\n");
        if (iaicr != RT9455_IAICR_NO_LIMIT) {
                ret = regmap_field_write(info->regmap_fields[F_IAICR],
                                         RT9455_IAICR_NO_LIMIT);
                if (ret) {
                        dev_err(dev, "Failed to set IAICR value\n");
                        return NOTIFY_DONE;
                }
        }

        return NOTIFY_OK;
}

static int rt9455_usb_event(struct notifier_block *nb,
                            unsigned long event, void *power)
{
        struct rt9455_info *info = container_of(nb, struct rt9455_info, nb);
        struct device *dev = &info->client->dev;
        unsigned int opa_mode, iaicr;
        int ret;

        /*
         * Determine whether the charger is in charge mode
         * or in boost mode.
         */
        ret = regmap_field_read(info->regmap_fields[F_OPA_MODE],
                                &opa_mode);
        if (ret) {
                dev_err(dev, "Failed to read OPA_MODE value\n");
                return NOTIFY_DONE;
        }

        ret = regmap_field_read(info->regmap_fields[F_IAICR],
                                &iaicr);
        if (ret) {
                dev_err(dev, "Failed to read IAICR value\n");
                return NOTIFY_DONE;
        }

        dev_dbg(dev, "Received USB event %lu\n", event);
        switch (event) {
        case USB_EVENT_NONE:
                return rt9455_usb_event_none(info, opa_mode, iaicr);
        case USB_EVENT_VBUS:
                return rt9455_usb_event_vbus(info, opa_mode, iaicr);
        case USB_EVENT_ID:
                return rt9455_usb_event_id(info, opa_mode, iaicr);
        case USB_EVENT_CHARGER:
                return rt9455_usb_event_charger(info, opa_mode, iaicr);
        default:
                dev_err(dev, "Unknown USB event\n");
        }
        return NOTIFY_DONE;
}
#endif

static void rt9455_pwr_rdy_work_callback(struct work_struct *work)
{
        struct rt9455_info *info = container_of(work, struct rt9455_info,
                                                pwr_rdy_work.work);
        struct device *dev = &info->client->dev;
        unsigned int pwr_rdy;
        int ret;

        ret = regmap_field_read(info->regmap_fields[F_PWR_RDY], &pwr_rdy);
        if (ret) {
                dev_err(dev, "Failed to read PWR_RDY bit\n");
                return;
        }
        switch (pwr_rdy) {
        case RT9455_PWR_FAULT:
                dev_dbg(dev, "Charger disconnected from power source\n");
                cancel_delayed_work_sync(&info->max_charging_time_work);
                break;
        case RT9455_PWR_GOOD:
                dev_dbg(dev, "Charger connected to power source\n");
                ret = regmap_field_write(info->regmap_fields[F_CHG_EN],
                                         RT9455_CHARGE_ENABLE);
                if (ret) {
                        dev_err(dev, "Failed to enable charging\n");
                        return;
                }
                queue_delayed_work(system_power_efficient_wq,
                                   &info->max_charging_time_work,
                                   RT9455_MAX_CHARGING_TIME * HZ);
                break;
        }
        /*
         * Notify userspace that the charger has been either connected to or
         * disconnected from the power source.
         */
        power_supply_changed(info->charger);
}

static void rt9455_max_charging_time_work_callback(struct work_struct *work)
{
        struct rt9455_info *info = container_of(work, struct rt9455_info,
                                                max_charging_time_work.work);
        struct device *dev = &info->client->dev;
        int ret;

        dev_err(dev, "Battery has been charging for at least 6 hours and is not yet fully charged. Battery is dead, therefore charging is disabled.\n");
        ret = regmap_field_write(info->regmap_fields[F_CHG_EN],
                                 RT9455_CHARGE_DISABLE);
        if (ret)
                dev_err(dev, "Failed to disable charging\n");
}

static void rt9455_batt_presence_work_callback(struct work_struct *work)
{
        struct rt9455_info *info = container_of(work, struct rt9455_info,
                                                batt_presence_work.work);
        struct device *dev = &info->client->dev;
        unsigned int irq1, mask1;
        int ret;

        ret = regmap_read(info->regmap, RT9455_REG_IRQ1, &irq1);
        if (ret) {
                dev_err(dev, "Failed to read IRQ1 register\n");
                return;
        }

        /*
         * If the battery is still absent, batt_presence_work is rescheduled.
         * Otherwise, max_charging_time is scheduled.
         */
        if (irq1 & GET_MASK(F_BATAB)) {
                queue_delayed_work(system_power_efficient_wq,
                                   &info->batt_presence_work,
                                   RT9455_BATT_PRESENCE_DELAY * HZ);
        } else {
                queue_delayed_work(system_power_efficient_wq,
                                   &info->max_charging_time_work,
                                   RT9455_MAX_CHARGING_TIME * HZ);

                ret = regmap_read(info->regmap, RT9455_REG_MASK1, &mask1);
                if (ret) {
                        dev_err(dev, "Failed to read MASK1 register\n");
                        return;
                }

                if (mask1 & GET_MASK(F_BATABM)) {
                        ret = regmap_field_write(info->regmap_fields[F_BATABM],
                                                 0x00);
                        if (ret)
                                dev_err(dev, "Failed to unmask BATAB interrupt\n");
                }
                /*
                 * Notify userspace that the battery is now connected to the
                 * charger.
                 */
                power_supply_changed(info->charger);
        }
}

static const struct power_supply_desc rt9455_charger_desc = {
        .name                   = RT9455_DRIVER_NAME,
        .type                   = POWER_SUPPLY_TYPE_USB,
        .properties             = rt9455_charger_properties,
        .num_properties         = ARRAY_SIZE(rt9455_charger_properties),
        .get_property           = rt9455_charger_get_property,
};

static bool rt9455_is_writeable_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case RT9455_REG_DEV_ID:
        case RT9455_REG_IRQ1:
        case RT9455_REG_IRQ2:
        case RT9455_REG_IRQ3:
                return false;
        default:
                return true;
        }
}

static bool rt9455_is_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case RT9455_REG_DEV_ID:
        case RT9455_REG_CTRL5:
        case RT9455_REG_CTRL6:
                return false;
        default:
                return true;
        }
}

static const struct regmap_config rt9455_regmap_config = {
        .reg_bits       = 8,
        .val_bits       = 8,
        .writeable_reg  = rt9455_is_writeable_reg,
        .volatile_reg   = rt9455_is_volatile_reg,
        .max_register   = RT9455_REG_MASK3,
        .cache_type     = REGCACHE_RBTREE,
};

static int rt9455_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
        struct device *dev = &client->dev;
        struct rt9455_info *info;
        struct power_supply_config rt9455_charger_config = {};
        /*
         * Mandatory device-specific data values. Also, VOREG and boost output
         * voltage are mandatory values, but they are stored in rt9455_info
         * structure.
         */
        u32 ichrg, ieoc_percentage;
        /* Optional device-specific data values. */
        u32 mivr = -1, iaicr = -1;
        int i, ret;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
                dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
                return -ENODEV;
        }
        info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        info->client = client;
        i2c_set_clientdata(client, info);

        info->regmap = devm_regmap_init_i2c(client,
                                            &rt9455_regmap_config);
        if (IS_ERR(info->regmap)) {
                dev_err(dev, "Failed to initialize register map\n");
                return -EINVAL;
        }

        for (i = 0; i < F_MAX_FIELDS; i++) {
                info->regmap_fields[i] =
                        devm_regmap_field_alloc(dev, info->regmap,
                                                rt9455_reg_fields[i]);
                if (IS_ERR(info->regmap_fields[i])) {
                        dev_err(dev,
                                "Failed to allocate regmap field = %d\n", i);
                        return PTR_ERR(info->regmap_fields[i]);
                }
        }

        ret = rt9455_discover_charger(info, &ichrg, &ieoc_percentage,
                                      &mivr, &iaicr);
        if (ret) {
                dev_err(dev, "Failed to discover charger\n");
                return ret;
        }

#if IS_ENABLED(CONFIG_USB_PHY)
        info->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
        if (IS_ERR(info->usb_phy)) {
                dev_err(dev, "Failed to get USB transceiver\n");
        } else {
                info->nb.notifier_call = rt9455_usb_event;
                ret = usb_register_notifier(info->usb_phy, &info->nb);
                if (ret) {
                        dev_err(dev, "Failed to register USB notifier\n");
                        /*
                         * If usb_register_notifier() fails, set notifier_call
                         * to NULL, to avoid calling usb_unregister_notifier().
                         */
                        info->nb.notifier_call = NULL;
                }
        }
#endif

        INIT_DEFERRABLE_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
        INIT_DEFERRABLE_WORK(&info->max_charging_time_work,
                             rt9455_max_charging_time_work_callback);
        INIT_DEFERRABLE_WORK(&info->batt_presence_work,
                             rt9455_batt_presence_work_callback);

        rt9455_charger_config.of_node           = dev->of_node;
        rt9455_charger_config.drv_data          = info;
        rt9455_charger_config.supplied_to       = rt9455_charger_supplied_to;
        rt9455_charger_config.num_supplicants   =
                                        ARRAY_SIZE(rt9455_charger_supplied_to);
        ret = devm_request_threaded_irq(dev, client->irq, NULL,
                                        rt9455_irq_handler_thread,
                                        IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                        RT9455_DRIVER_NAME, info);
        if (ret) {
                dev_err(dev, "Failed to register IRQ handler\n");
                goto put_usb_notifier;
        }

        ret = rt9455_hw_init(info, ichrg, ieoc_percentage, mivr, iaicr);
        if (ret) {
                dev_err(dev, "Failed to set charger to its default values\n");
                goto put_usb_notifier;
        }

        info->charger = devm_power_supply_register(dev, &rt9455_charger_desc,
                                                   &rt9455_charger_config);
        if (IS_ERR(info->charger)) {
                dev_err(dev, "Failed to register charger\n");
                ret = PTR_ERR(info->charger);
                goto put_usb_notifier;
        }

        return 0;

put_usb_notifier:
#if IS_ENABLED(CONFIG_USB_PHY)
        if (info->nb.notifier_call)  {
                usb_unregister_notifier(info->usb_phy, &info->nb);
                info->nb.notifier_call = NULL;
        }
#endif
        return ret;
}

static int rt9455_remove(struct i2c_client *client)
{
        int ret;
        struct rt9455_info *info = i2c_get_clientdata(client);

        ret = rt9455_register_reset(info);
        if (ret)
                dev_err(&info->client->dev, "Failed to set charger to its default values\n");

#if IS_ENABLED(CONFIG_USB_PHY)
        if (info->nb.notifier_call)
                usb_unregister_notifier(info->usb_phy, &info->nb);
#endif

        cancel_delayed_work_sync(&info->pwr_rdy_work);
        cancel_delayed_work_sync(&info->max_charging_time_work);
        cancel_delayed_work_sync(&info->batt_presence_work);

        return ret;
}

static const struct i2c_device_id rt9455_i2c_id_table[] = {
        { RT9455_DRIVER_NAME, 0 },
        { },
};
MODULE_DEVICE_TABLE(i2c, rt9455_i2c_id_table);

static const struct of_device_id rt9455_of_match[] = {
        { .compatible = "richtek,rt9455", },
        { },
};
MODULE_DEVICE_TABLE(of, rt9455_of_match);

static const struct acpi_device_id rt9455_i2c_acpi_match[] = {
        { "RT945500", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, rt9455_i2c_acpi_match);

static struct i2c_driver rt9455_driver = {
        .probe          = rt9455_probe,
        .remove         = rt9455_remove,
        .id_table       = rt9455_i2c_id_table,
        .driver = {
                .name           = RT9455_DRIVER_NAME,
                .of_match_table = of_match_ptr(rt9455_of_match),
                .acpi_match_table = ACPI_PTR(rt9455_i2c_acpi_match),
        },
};
module_i2c_driver(rt9455_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Anda-Maria Nicolae <anda-maria.nicolae@intel.com>");
MODULE_DESCRIPTION("Richtek RT9455 Charger Driver");