// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * bq2415x charger driver
 *
 * Copyright (C) 2011-2013  Pali Rohár <pali@kernel.org>
 *
 * Datasheets:
 * https://www.ti.com/product/bq24150
 * https://www.ti.com/product/bq24150a
 * https://www.ti.com/product/bq24152
 * https://www.ti.com/product/bq24153
 * https://www.ti.com/product/bq24153a
 * https://www.ti.com/product/bq24155
 * https://www.ti.com/product/bq24157s
 * https://www.ti.com/product/bq24158
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/err.h>
#include <linux/workqueue.h>
#include <linux/sysfs.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/idr.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/acpi.h>

#include <linux/power/bq2415x_charger.h>

/* timeout for resetting chip timer */
#define BQ2415X_TIMER_TIMEOUT           10

#define BQ2415X_REG_STATUS              0x00
#define BQ2415X_REG_CONTROL             0x01
#define BQ2415X_REG_VOLTAGE             0x02
#define BQ2415X_REG_VENDER              0x03
#define BQ2415X_REG_CURRENT             0x04

/* reset state for all registers */
#define BQ2415X_RESET_STATUS            BIT(6)
#define BQ2415X_RESET_CONTROL           (BIT(4)|BIT(5))
#define BQ2415X_RESET_VOLTAGE           (BIT(1)|BIT(3))
#define BQ2415X_RESET_CURRENT           (BIT(0)|BIT(3)|BIT(7))

/* status register */
#define BQ2415X_BIT_TMR_RST             7
#define BQ2415X_BIT_OTG                 7
#define BQ2415X_BIT_EN_STAT             6
#define BQ2415X_MASK_STAT               (BIT(4)|BIT(5))
#define BQ2415X_SHIFT_STAT              4
#define BQ2415X_BIT_BOOST               3
#define BQ2415X_MASK_FAULT              (BIT(0)|BIT(1)|BIT(2))
#define BQ2415X_SHIFT_FAULT             0

/* control register */
#define BQ2415X_MASK_LIMIT              (BIT(6)|BIT(7))
#define BQ2415X_SHIFT_LIMIT             6
#define BQ2415X_MASK_VLOWV              (BIT(4)|BIT(5))
#define BQ2415X_SHIFT_VLOWV             4
#define BQ2415X_BIT_TE                  3
#define BQ2415X_BIT_CE                  2
#define BQ2415X_BIT_HZ_MODE             1
#define BQ2415X_BIT_OPA_MODE            0

/* voltage register */
#define BQ2415X_MASK_VO         (BIT(2)|BIT(3)|BIT(4)|BIT(5)|BIT(6)|BIT(7))
#define BQ2415X_SHIFT_VO                2
#define BQ2415X_BIT_OTG_PL              1
#define BQ2415X_BIT_OTG_EN              0

/* vender register */
#define BQ2415X_MASK_VENDER             (BIT(5)|BIT(6)|BIT(7))
#define BQ2415X_SHIFT_VENDER            5
#define BQ2415X_MASK_PN                 (BIT(3)|BIT(4))
#define BQ2415X_SHIFT_PN                3
#define BQ2415X_MASK_REVISION           (BIT(0)|BIT(1)|BIT(2))
#define BQ2415X_SHIFT_REVISION          0

/* current register */
#define BQ2415X_MASK_RESET              BIT(7)
#define BQ2415X_MASK_VI_CHRG            (BIT(4)|BIT(5)|BIT(6))
#define BQ2415X_SHIFT_VI_CHRG           4
/* N/A                                  BIT(3) */
#define BQ2415X_MASK_VI_TERM            (BIT(0)|BIT(1)|BIT(2))
#define BQ2415X_SHIFT_VI_TERM           0


enum bq2415x_command {
        BQ2415X_TIMER_RESET,
        BQ2415X_OTG_STATUS,
        BQ2415X_STAT_PIN_STATUS,
        BQ2415X_STAT_PIN_ENABLE,
        BQ2415X_STAT_PIN_DISABLE,
        BQ2415X_CHARGE_STATUS,
        BQ2415X_BOOST_STATUS,
        BQ2415X_FAULT_STATUS,

        BQ2415X_CHARGE_TERMINATION_STATUS,
        BQ2415X_CHARGE_TERMINATION_ENABLE,
        BQ2415X_CHARGE_TERMINATION_DISABLE,
        BQ2415X_CHARGER_STATUS,
        BQ2415X_CHARGER_ENABLE,
        BQ2415X_CHARGER_DISABLE,
        BQ2415X_HIGH_IMPEDANCE_STATUS,
        BQ2415X_HIGH_IMPEDANCE_ENABLE,
        BQ2415X_HIGH_IMPEDANCE_DISABLE,
        BQ2415X_BOOST_MODE_STATUS,
        BQ2415X_BOOST_MODE_ENABLE,
        BQ2415X_BOOST_MODE_DISABLE,

        BQ2415X_OTG_LEVEL,
        BQ2415X_OTG_ACTIVATE_HIGH,
        BQ2415X_OTG_ACTIVATE_LOW,
        BQ2415X_OTG_PIN_STATUS,
        BQ2415X_OTG_PIN_ENABLE,
        BQ2415X_OTG_PIN_DISABLE,

        BQ2415X_VENDER_CODE,
        BQ2415X_PART_NUMBER,
        BQ2415X_REVISION,
};

enum bq2415x_chip {
        BQUNKNOWN,
        BQ24150,
        BQ24150A,
        BQ24151,
        BQ24151A,
        BQ24152,
        BQ24153,
        BQ24153A,
        BQ24155,
        BQ24156,
        BQ24156A,
        BQ24157S,
        BQ24158,
};

static char *bq2415x_chip_name[] = {
        "unknown",
        "bq24150",
        "bq24150a",
        "bq24151",
        "bq24151a",
        "bq24152",
        "bq24153",
        "bq24153a",
        "bq24155",
        "bq24156",
        "bq24156a",
        "bq24157s",
        "bq24158",
};

struct bq2415x_device {
        struct device *dev;
        struct bq2415x_platform_data init_data;
        struct power_supply *charger;
        struct power_supply_desc charger_desc;
        struct delayed_work work;
        struct device_node *notify_node;
        struct notifier_block nb;
        enum bq2415x_mode reported_mode;/* mode reported by hook function */
        enum bq2415x_mode mode;         /* currently configured mode */
        enum bq2415x_chip chip;
        const char *timer_error;
        char *model;
        char *name;
        int autotimer;  /* 1 - if driver automatically reset timer, 0 - not */
        int automode;   /* 1 - enabled, 0 - disabled; -1 - not supported */
        int charge_status;
        int id;
};

/* each registered chip must have unique id */
static DEFINE_IDR(bq2415x_id);

static DEFINE_MUTEX(bq2415x_id_mutex);
static DEFINE_MUTEX(bq2415x_timer_mutex);
static DEFINE_MUTEX(bq2415x_i2c_mutex);

/**** i2c read functions ****/

/* read value from register */
static int bq2415x_i2c_read(struct bq2415x_device *bq, u8 reg)
{
        struct i2c_client *client = to_i2c_client(bq->dev);
        struct i2c_msg msg[2];
        u8 val;
        int ret;

        if (!client->adapter)
                return -ENODEV;

        msg[0].addr = client->addr;
        msg[0].flags = 0;
        msg[0].buf = &reg;
        msg[0].len = sizeof(reg);
        msg[1].addr = client->addr;
        msg[1].flags = I2C_M_RD;
        msg[1].buf = &val;
        msg[1].len = sizeof(val);

        mutex_lock(&bq2415x_i2c_mutex);
        ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
        mutex_unlock(&bq2415x_i2c_mutex);

        if (ret < 0)
                return ret;

        return val;
}

/* read value from register, apply mask and right shift it */
static int bq2415x_i2c_read_mask(struct bq2415x_device *bq, u8 reg,
                                 u8 mask, u8 shift)
{
        int ret;

        if (shift > 8)
                return -EINVAL;

        ret = bq2415x_i2c_read(bq, reg);
        if (ret < 0)
                return ret;
        return (ret & mask) >> shift;
}

/* read value from register and return one specified bit */
static int bq2415x_i2c_read_bit(struct bq2415x_device *bq, u8 reg, u8 bit)
{
        if (bit > 8)
                return -EINVAL;
        return bq2415x_i2c_read_mask(bq, reg, BIT(bit), bit);
}

/**** i2c write functions ****/

/* write value to register */
static int bq2415x_i2c_write(struct bq2415x_device *bq, u8 reg, u8 val)
{
        struct i2c_client *client = to_i2c_client(bq->dev);
        struct i2c_msg msg[1];
        u8 data[2];
        int ret;

        data[0] = reg;
        data[1] = val;

        msg[0].addr = client->addr;
        msg[0].flags = 0;
        msg[0].buf = data;
        msg[0].len = ARRAY_SIZE(data);

        mutex_lock(&bq2415x_i2c_mutex);
        ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
        mutex_unlock(&bq2415x_i2c_mutex);

        /* i2c_transfer returns number of messages transferred */
        if (ret < 0)
                return ret;
        else if (ret != 1)
                return -EIO;

        return 0;
}

/* read value from register, change it with mask left shifted and write back */
static int bq2415x_i2c_write_mask(struct bq2415x_device *bq, u8 reg, u8 val,
                                  u8 mask, u8 shift)
{
        int ret;

        if (shift > 8)
                return -EINVAL;

        ret = bq2415x_i2c_read(bq, reg);
        if (ret < 0)
                return ret;

        ret &= ~mask;
        ret |= val << shift;

        return bq2415x_i2c_write(bq, reg, ret);
}

/* change only one bit in register */
static int bq2415x_i2c_write_bit(struct bq2415x_device *bq, u8 reg,
                                 bool val, u8 bit)
{
        if (bit > 8)
                return -EINVAL;
        return bq2415x_i2c_write_mask(bq, reg, val, BIT(bit), bit);
}

/**** global functions ****/

/* exec command function */
static int bq2415x_exec_command(struct bq2415x_device *bq,
                                enum bq2415x_command command)
{
        int ret;

        switch (command) {
        case BQ2415X_TIMER_RESET:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_STATUS,
                                1, BQ2415X_BIT_TMR_RST);
        case BQ2415X_OTG_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_STATUS,
                                BQ2415X_BIT_OTG);
        case BQ2415X_STAT_PIN_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_STATUS,
                                BQ2415X_BIT_EN_STAT);
        case BQ2415X_STAT_PIN_ENABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_STATUS, 1,
                                BQ2415X_BIT_EN_STAT);
        case BQ2415X_STAT_PIN_DISABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_STATUS, 0,
                                BQ2415X_BIT_EN_STAT);
        case BQ2415X_CHARGE_STATUS:
                return bq2415x_i2c_read_mask(bq, BQ2415X_REG_STATUS,
                                BQ2415X_MASK_STAT, BQ2415X_SHIFT_STAT);
        case BQ2415X_BOOST_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_STATUS,
                                BQ2415X_BIT_BOOST);
        case BQ2415X_FAULT_STATUS:
                return bq2415x_i2c_read_mask(bq, BQ2415X_REG_STATUS,
                        BQ2415X_MASK_FAULT, BQ2415X_SHIFT_FAULT);

        case BQ2415X_CHARGE_TERMINATION_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_CONTROL,
                                BQ2415X_BIT_TE);
        case BQ2415X_CHARGE_TERMINATION_ENABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                1, BQ2415X_BIT_TE);
        case BQ2415X_CHARGE_TERMINATION_DISABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                0, BQ2415X_BIT_TE);
        case BQ2415X_CHARGER_STATUS:
                ret = bq2415x_i2c_read_bit(bq, BQ2415X_REG_CONTROL,
                        BQ2415X_BIT_CE);
                if (ret < 0)
                        return ret;
                return ret > 0 ? 0 : 1;
        case BQ2415X_CHARGER_ENABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                0, BQ2415X_BIT_CE);
        case BQ2415X_CHARGER_DISABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                1, BQ2415X_BIT_CE);
        case BQ2415X_HIGH_IMPEDANCE_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_CONTROL,
                                BQ2415X_BIT_HZ_MODE);
        case BQ2415X_HIGH_IMPEDANCE_ENABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                1, BQ2415X_BIT_HZ_MODE);
        case BQ2415X_HIGH_IMPEDANCE_DISABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                0, BQ2415X_BIT_HZ_MODE);
        case BQ2415X_BOOST_MODE_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_CONTROL,
                                BQ2415X_BIT_OPA_MODE);
        case BQ2415X_BOOST_MODE_ENABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                1, BQ2415X_BIT_OPA_MODE);
        case BQ2415X_BOOST_MODE_DISABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_CONTROL,
                                0, BQ2415X_BIT_OPA_MODE);

        case BQ2415X_OTG_LEVEL:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_VOLTAGE,
                                BQ2415X_BIT_OTG_PL);
        case BQ2415X_OTG_ACTIVATE_HIGH:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_VOLTAGE,
                                1, BQ2415X_BIT_OTG_PL);
        case BQ2415X_OTG_ACTIVATE_LOW:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_VOLTAGE,
                                0, BQ2415X_BIT_OTG_PL);
        case BQ2415X_OTG_PIN_STATUS:
                return bq2415x_i2c_read_bit(bq, BQ2415X_REG_VOLTAGE,
                                BQ2415X_BIT_OTG_EN);
        case BQ2415X_OTG_PIN_ENABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_VOLTAGE,
                                1, BQ2415X_BIT_OTG_EN);
        case BQ2415X_OTG_PIN_DISABLE:
                return bq2415x_i2c_write_bit(bq, BQ2415X_REG_VOLTAGE,
                                0, BQ2415X_BIT_OTG_EN);

        case BQ2415X_VENDER_CODE:
                return bq2415x_i2c_read_mask(bq, BQ2415X_REG_VENDER,
                        BQ2415X_MASK_VENDER, BQ2415X_SHIFT_VENDER);
        case BQ2415X_PART_NUMBER:
                return bq2415x_i2c_read_mask(bq, BQ2415X_REG_VENDER,
                                BQ2415X_MASK_PN, BQ2415X_SHIFT_PN);
        case BQ2415X_REVISION:
                return bq2415x_i2c_read_mask(bq, BQ2415X_REG_VENDER,
                        BQ2415X_MASK_REVISION, BQ2415X_SHIFT_REVISION);
        }
        return -EINVAL;
}

/* detect chip type */
static enum bq2415x_chip bq2415x_detect_chip(struct bq2415x_device *bq)
{
        struct i2c_client *client = to_i2c_client(bq->dev);
        int ret = bq2415x_exec_command(bq, BQ2415X_PART_NUMBER);

        if (ret < 0)
                return ret;

        switch (client->addr) {
        case 0x6b:
                switch (ret) {
                case 0:
                        if (bq->chip == BQ24151A)
                                return bq->chip;
                        return BQ24151;
                case 1:
                        if (bq->chip == BQ24150A ||
                                bq->chip == BQ24152 ||
                                bq->chip == BQ24155)
                                return bq->chip;
                        return BQ24150;
                case 2:
                        if (bq->chip == BQ24153A)
                                return bq->chip;
                        return BQ24153;
                default:
                        return BQUNKNOWN;
                }
                break;

        case 0x6a:
                switch (ret) {
                case 0:
                        if (bq->chip == BQ24156A)
                                return bq->chip;
                        return BQ24156;
                case 2:
                        if (bq->chip == BQ24157S)
                                return bq->chip;
                        return BQ24158;
                default:
                        return BQUNKNOWN;
                }
                break;
        }

        return BQUNKNOWN;
}

/* detect chip revision */
static int bq2415x_detect_revision(struct bq2415x_device *bq)
{
        int ret = bq2415x_exec_command(bq, BQ2415X_REVISION);
        int chip = bq2415x_detect_chip(bq);

        if (ret < 0 || chip < 0)
                return -1;

        switch (chip) {
        case BQ24150:
        case BQ24150A:
        case BQ24151:
        case BQ24151A:
        case BQ24152:
                if (ret >= 0 && ret <= 3)
                        return ret;
                return -1;
        case BQ24153:
        case BQ24153A:
        case BQ24156:
        case BQ24156A:
        case BQ24157S:
        case BQ24158:
                if (ret == 3)
                        return 0;
                else if (ret == 1)
                        return 1;
                return -1;
        case BQ24155:
                if (ret == 3)
                        return 3;
                return -1;
        case BQUNKNOWN:
                return -1;
        }

        return -1;
}

/* return chip vender code */
static int bq2415x_get_vender_code(struct bq2415x_device *bq)
{
        int ret;

        ret = bq2415x_exec_command(bq, BQ2415X_VENDER_CODE);
        if (ret < 0)
                return 0;

        /* convert to binary */
        return (ret & 0x1) +
               ((ret >> 1) & 0x1) * 10 +
               ((ret >> 2) & 0x1) * 100;
}

/* reset all chip registers to default state */
static void bq2415x_reset_chip(struct bq2415x_device *bq)
{
        bq2415x_i2c_write(bq, BQ2415X_REG_CURRENT, BQ2415X_RESET_CURRENT);
        bq2415x_i2c_write(bq, BQ2415X_REG_VOLTAGE, BQ2415X_RESET_VOLTAGE);
        bq2415x_i2c_write(bq, BQ2415X_REG_CONTROL, BQ2415X_RESET_CONTROL);
        bq2415x_i2c_write(bq, BQ2415X_REG_STATUS, BQ2415X_RESET_STATUS);
        bq->timer_error = NULL;
}

/**** properties functions ****/

/* set current limit in mA */
static int bq2415x_set_current_limit(struct bq2415x_device *bq, int mA)
{
        int val;

        if (mA <= 100)
                val = 0;
        else if (mA <= 500)
                val = 1;
        else if (mA <= 800)
                val = 2;
        else
                val = 3;

        return bq2415x_i2c_write_mask(bq, BQ2415X_REG_CONTROL, val,
                        BQ2415X_MASK_LIMIT, BQ2415X_SHIFT_LIMIT);
}

/* get current limit in mA */
static int bq2415x_get_current_limit(struct bq2415x_device *bq)
{
        int ret;

        ret = bq2415x_i2c_read_mask(bq, BQ2415X_REG_CONTROL,
                        BQ2415X_MASK_LIMIT, BQ2415X_SHIFT_LIMIT);
        if (ret < 0)
                return ret;
        else if (ret == 0)
                return 100;
        else if (ret == 1)
                return 500;
        else if (ret == 2)
                return 800;
        else if (ret == 3)
                return 1800;
        return -EINVAL;
}

/* set weak battery voltage in mV */
static int bq2415x_set_weak_battery_voltage(struct bq2415x_device *bq, int mV)
{
        int val;

        /* round to 100mV */
        if (mV <= 3400 + 50)
                val = 0;
        else if (mV <= 3500 + 50)
                val = 1;
        else if (mV <= 3600 + 50)
                val = 2;
        else
                val = 3;

        return bq2415x_i2c_write_mask(bq, BQ2415X_REG_CONTROL, val,
                        BQ2415X_MASK_VLOWV, BQ2415X_SHIFT_VLOWV);
}

/* get weak battery voltage in mV */
static int bq2415x_get_weak_battery_voltage(struct bq2415x_device *bq)
{
        int ret;

        ret = bq2415x_i2c_read_mask(bq, BQ2415X_REG_CONTROL,
                        BQ2415X_MASK_VLOWV, BQ2415X_SHIFT_VLOWV);
        if (ret < 0)
                return ret;
        return 100 * (34 + ret);
}

/* set battery regulation voltage in mV */
static int bq2415x_set_battery_regulation_voltage(struct bq2415x_device *bq,
                                                  int mV)
{
        int val = (mV/10 - 350) / 2;

        /*
         * According to datasheet, maximum battery regulation voltage is
         * 4440mV which is b101111 = 47.
         */
        if (val < 0)
                val = 0;
        else if (val > 47)
                return -EINVAL;

        return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,
                        BQ2415X_MASK_VO, BQ2415X_SHIFT_VO);
}

/* get battery regulation voltage in mV */
static int bq2415x_get_battery_regulation_voltage(struct bq2415x_device *bq)
{
        int ret = bq2415x_i2c_read_mask(bq, BQ2415X_REG_VOLTAGE,
                        BQ2415X_MASK_VO, BQ2415X_SHIFT_VO);

        if (ret < 0)
                return ret;
        return 10 * (350 + 2*ret);
}

/* set charge current in mA (platform data must provide resistor sense) */
static int bq2415x_set_charge_current(struct bq2415x_device *bq, int mA)
{
        int val;

        if (bq->init_data.resistor_sense <= 0)
                return -EINVAL;

        val = (mA * bq->init_data.resistor_sense - 37400) / 6800;
        if (val < 0)
                val = 0;
        else if (val > 7)
                val = 7;

        return bq2415x_i2c_write_mask(bq, BQ2415X_REG_CURRENT, val,
                        BQ2415X_MASK_VI_CHRG | BQ2415X_MASK_RESET,
                        BQ2415X_SHIFT_VI_CHRG);
}

/* get charge current in mA (platform data must provide resistor sense) */
static int bq2415x_get_charge_current(struct bq2415x_device *bq)
{
        int ret;

        if (bq->init_data.resistor_sense <= 0)
                return -EINVAL;

        ret = bq2415x_i2c_read_mask(bq, BQ2415X_REG_CURRENT,
                        BQ2415X_MASK_VI_CHRG, BQ2415X_SHIFT_VI_CHRG);
        if (ret < 0)
                return ret;
        return (37400 + 6800*ret) / bq->init_data.resistor_sense;
}

/* set termination current in mA (platform data must provide resistor sense) */
static int bq2415x_set_termination_current(struct bq2415x_device *bq, int mA)
{
        int val;

        if (bq->init_data.resistor_sense <= 0)
                return -EINVAL;

        val = (mA * bq->init_data.resistor_sense - 3400) / 3400;
        if (val < 0)
                val = 0;
        else if (val > 7)
                val = 7;

        return bq2415x_i2c_write_mask(bq, BQ2415X_REG_CURRENT, val,
                        BQ2415X_MASK_VI_TERM | BQ2415X_MASK_RESET,
                        BQ2415X_SHIFT_VI_TERM);
}

/* get termination current in mA (platform data must provide resistor sense) */
static int bq2415x_get_termination_current(struct bq2415x_device *bq)
{
        int ret;

        if (bq->init_data.resistor_sense <= 0)
                return -EINVAL;

        ret = bq2415x_i2c_read_mask(bq, BQ2415X_REG_CURRENT,
                        BQ2415X_MASK_VI_TERM, BQ2415X_SHIFT_VI_TERM);
        if (ret < 0)
                return ret;
        return (3400 + 3400*ret) / bq->init_data.resistor_sense;
}

/* set default value of property */
#define bq2415x_set_default_value(bq, prop) \
        do { \
                int ret = 0; \
                if (bq->init_data.prop != -1) \
                        ret = bq2415x_set_##prop(bq, bq->init_data.prop); \
                if (ret < 0) \
                        return ret; \
        } while (0)

/* set default values of all properties */
static int bq2415x_set_defaults(struct bq2415x_device *bq)
{
        bq2415x_exec_command(bq, BQ2415X_BOOST_MODE_DISABLE);
        bq2415x_exec_command(bq, BQ2415X_CHARGER_DISABLE);
        bq2415x_exec_command(bq, BQ2415X_CHARGE_TERMINATION_DISABLE);

        bq2415x_set_default_value(bq, current_limit);
        bq2415x_set_default_value(bq, weak_battery_voltage);
        bq2415x_set_default_value(bq, battery_regulation_voltage);

        if (bq->init_data.resistor_sense > 0) {
                bq2415x_set_default_value(bq, charge_current);
                bq2415x_set_default_value(bq, termination_current);
                bq2415x_exec_command(bq, BQ2415X_CHARGE_TERMINATION_ENABLE);
        }

        bq2415x_exec_command(bq, BQ2415X_CHARGER_ENABLE);
        return 0;
}

/**** charger mode functions ****/

/* set charger mode */
static int bq2415x_set_mode(struct bq2415x_device *bq, enum bq2415x_mode mode)
{
        int ret = 0;
        int charger = 0;
        int boost = 0;

        if (mode == BQ2415X_MODE_BOOST)
                boost = 1;
        else if (mode != BQ2415X_MODE_OFF)
                charger = 1;

        if (!charger)
                ret = bq2415x_exec_command(bq, BQ2415X_CHARGER_DISABLE);

        if (!boost)
                ret = bq2415x_exec_command(bq, BQ2415X_BOOST_MODE_DISABLE);

        if (ret < 0)
                return ret;

        switch (mode) {
        case BQ2415X_MODE_OFF:
                dev_dbg(bq->dev, "changing mode to: Offline\n");
                ret = bq2415x_set_current_limit(bq, 100);
                break;
        case BQ2415X_MODE_NONE:
                dev_dbg(bq->dev, "changing mode to: N/A\n");
                ret = bq2415x_set_current_limit(bq, 100);
                break;
        case BQ2415X_MODE_HOST_CHARGER:
                dev_dbg(bq->dev, "changing mode to: Host/HUB charger\n");
                ret = bq2415x_set_current_limit(bq, 500);
                break;
        case BQ2415X_MODE_DEDICATED_CHARGER:
                dev_dbg(bq->dev, "changing mode to: Dedicated charger\n");
                ret = bq2415x_set_current_limit(bq, 1800);
                break;
        case BQ2415X_MODE_BOOST: /* Boost mode */
                dev_dbg(bq->dev, "changing mode to: Boost\n");
                ret = bq2415x_set_current_limit(bq, 100);
                break;
        }

        if (ret < 0)
                return ret;

        if (charger)
                ret = bq2415x_exec_command(bq, BQ2415X_CHARGER_ENABLE);
        else if (boost)
                ret = bq2415x_exec_command(bq, BQ2415X_BOOST_MODE_ENABLE);

        if (ret < 0)
                return ret;

        bq2415x_set_default_value(bq, weak_battery_voltage);
        bq2415x_set_default_value(bq, battery_regulation_voltage);

        bq->mode = mode;
        sysfs_notify(&bq->charger->dev.kobj, NULL, "mode");

        return 0;

}

static bool bq2415x_update_reported_mode(struct bq2415x_device *bq, int mA)
{
        enum bq2415x_mode mode;

        if (mA == 0)
                mode = BQ2415X_MODE_OFF;
        else if (mA < 500)
                mode = BQ2415X_MODE_NONE;
        else if (mA < 1800)
                mode = BQ2415X_MODE_HOST_CHARGER;
        else
                mode = BQ2415X_MODE_DEDICATED_CHARGER;

        if (bq->reported_mode == mode)
                return false;

        bq->reported_mode = mode;
        return true;
}

static int bq2415x_notifier_call(struct notifier_block *nb,
                unsigned long val, void *v)
{
        struct bq2415x_device *bq =
                container_of(nb, struct bq2415x_device, nb);
        struct power_supply *psy = v;
        union power_supply_propval prop;
        int ret;

        if (val != PSY_EVENT_PROP_CHANGED)
                return NOTIFY_OK;

        /* Ignore event if it was not send by notify_node/notify_device */
        if (bq->notify_node) {
                if (!psy->dev.parent ||
                    psy->dev.parent->of_node != bq->notify_node)
                        return NOTIFY_OK;
        } else if (bq->init_data.notify_device) {
                if (strcmp(psy->desc->name, bq->init_data.notify_device) != 0)
                        return NOTIFY_OK;
        }

        dev_dbg(bq->dev, "notifier call was called\n");

        ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_CURRENT_MAX,
                        &prop);
        if (ret != 0)
                return NOTIFY_OK;

        if (!bq2415x_update_reported_mode(bq, prop.intval))
                return NOTIFY_OK;

        power_supply_changed(bq->charger);

        /* if automode is not enabled do not tell about reported_mode */
        if (bq->automode < 1)
                return NOTIFY_OK;

        mod_delayed_work(system_percpu_wq, &bq->work, 0);

        return NOTIFY_OK;
}

/**** timer functions ****/

/* enable/disable auto resetting chip timer */
static void bq2415x_set_autotimer(struct bq2415x_device *bq, int state)
{
        mutex_lock(&bq2415x_timer_mutex);

        if (bq->autotimer == state) {
                mutex_unlock(&bq2415x_timer_mutex);
                return;
        }

        bq->autotimer = state;

        if (state) {
                schedule_delayed_work(&bq->work, BQ2415X_TIMER_TIMEOUT * HZ);
                bq2415x_exec_command(bq, BQ2415X_TIMER_RESET);
                bq->timer_error = NULL;
        } else {
                cancel_delayed_work_sync(&bq->work);
        }

        mutex_unlock(&bq2415x_timer_mutex);
}

/* called by bq2415x_timer_work on timer error */
static void bq2415x_timer_error(struct bq2415x_device *bq, const char *msg)
{
        bq->timer_error = msg;
        sysfs_notify(&bq->charger->dev.kobj, NULL, "timer");
        dev_err(bq->dev, "%s\n", msg);
        if (bq->automode > 0)
                bq->automode = 0;
        bq2415x_set_mode(bq, BQ2415X_MODE_OFF);
        bq2415x_set_autotimer(bq, 0);
}

/* delayed work function for auto resetting chip timer */
static void bq2415x_timer_work(struct work_struct *work)
{
        struct bq2415x_device *bq = container_of(work, struct bq2415x_device,
                                                 work.work);
        int ret;
        int error;
        int boost;
        int charge;

        if (bq->automode > 0 && (bq->reported_mode != bq->mode)) {
                sysfs_notify(&bq->charger->dev.kobj, NULL, "reported_mode");
                bq2415x_set_mode(bq, bq->reported_mode);
        }

        charge = bq2415x_exec_command(bq, BQ2415X_CHARGE_STATUS);
        if (bq->charge_status != charge) {
                power_supply_changed(bq->charger);
                bq->charge_status = charge;
        }

        if (!bq->autotimer)
                return;

        ret = bq2415x_exec_command(bq, BQ2415X_TIMER_RESET);
        if (ret < 0) {
                bq2415x_timer_error(bq, "Resetting timer failed");
                return;
        }

        boost = bq2415x_exec_command(bq, BQ2415X_BOOST_MODE_STATUS);
        if (boost < 0) {
                bq2415x_timer_error(bq, "Unknown error");
                return;
        }

        error = bq2415x_exec_command(bq, BQ2415X_FAULT_STATUS);
        if (error < 0) {
                bq2415x_timer_error(bq, "Unknown error");
                return;
        }

        if (boost) {
                switch (error) {
                /* Non fatal errors, chip is OK */
                case 0: /* No error */
                        break;
                case 6: /* Timer expired */
                        dev_err(bq->dev, "Timer expired\n");
                        break;
                case 3: /* Battery voltage too low */
                        dev_err(bq->dev, "Battery voltage to low\n");
                        break;

                /* Fatal errors, disable and reset chip */
                case 1: /* Overvoltage protection (chip fried) */
                        bq2415x_timer_error(bq,
                                "Overvoltage protection (chip fried)");
                        return;
                case 2: /* Overload */
                        bq2415x_timer_error(bq, "Overload");
                        return;
                case 4: /* Battery overvoltage protection */
                        bq2415x_timer_error(bq,
                                "Battery overvoltage protection");
                        return;
                case 5: /* Thermal shutdown (too hot) */
                        bq2415x_timer_error(bq,
                                        "Thermal shutdown (too hot)");
                        return;
                case 7: /* N/A */
                        bq2415x_timer_error(bq, "Unknown error");
                        return;
                }
        } else {
                switch (error) {
                /* Non fatal errors, chip is OK */
                case 0: /* No error */
                        break;
                case 2: /* Sleep mode */
                        dev_err(bq->dev, "Sleep mode\n");
                        break;
                case 3: /* Poor input source */
                        dev_err(bq->dev, "Poor input source\n");
                        break;
                case 6: /* Timer expired */
                        dev_err(bq->dev, "Timer expired\n");
                        break;
                case 7: /* No battery */
                        dev_err(bq->dev, "No battery\n");
                        break;

                /* Fatal errors, disable and reset chip */
                case 1: /* Overvoltage protection (chip fried) */
                        bq2415x_timer_error(bq,
                                "Overvoltage protection (chip fried)");
                        return;
                case 4: /* Battery overvoltage protection */
                        bq2415x_timer_error(bq,
                                "Battery overvoltage protection");
                        return;
                case 5: /* Thermal shutdown (too hot) */
                        bq2415x_timer_error(bq,
                                "Thermal shutdown (too hot)");
                        return;
                }
        }

        schedule_delayed_work(&bq->work, BQ2415X_TIMER_TIMEOUT * HZ);
}

/**** power supply interface code ****/

static enum power_supply_property bq2415x_power_supply_props[] = {
        /* TODO: maybe add more power supply properties */
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_ONLINE,
};

static int bq2415x_power_supply_get_property(struct power_supply *psy,
                                             enum power_supply_property psp,
                                             union power_supply_propval *val)
{
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        int ret;

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                ret = bq2415x_exec_command(bq, BQ2415X_CHARGE_STATUS);
                if (ret < 0)
                        return ret;
                else if (ret == 0) /* Ready */
                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                else if (ret == 1) /* Charge in progress */
                        val->intval = POWER_SUPPLY_STATUS_CHARGING;
                else if (ret == 2) /* Charge done */
                        val->intval = POWER_SUPPLY_STATUS_FULL;
                else
                        val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
                break;
        case POWER_SUPPLY_PROP_MODEL_NAME:
                val->strval = bq->model;
                break;
        case POWER_SUPPLY_PROP_ONLINE:
                /* VBUS is present for all charging and fault states,
                 * except the 'Ready' state.
                 */
                ret = bq2415x_exec_command(bq, BQ2415X_CHARGE_STATUS);
                if (ret < 0)
                        return ret;
                val->intval = ret > 0;
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static void bq2415x_power_supply_exit(struct bq2415x_device *bq)
{
        bq->autotimer = 0;
        if (bq->automode > 0)
                bq->automode = 0;
        cancel_delayed_work_sync(&bq->work);
        power_supply_unregister(bq->charger);
        kfree(bq->model);
}

/**** additional sysfs entries for power supply interface ****/

/* show *_status entries */
static ssize_t bq2415x_sysfs_show_status(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        enum bq2415x_command command;
        int ret;

        if (strcmp(attr->attr.name, "otg_status") == 0)
                command = BQ2415X_OTG_STATUS;
        else if (strcmp(attr->attr.name, "charge_status") == 0)
                command = BQ2415X_CHARGE_STATUS;
        else if (strcmp(attr->attr.name, "boost_status") == 0)
                command = BQ2415X_BOOST_STATUS;
        else if (strcmp(attr->attr.name, "fault_status") == 0)
                command = BQ2415X_FAULT_STATUS;
        else
                return -EINVAL;

        ret = bq2415x_exec_command(bq, command);
        if (ret < 0)
                return ret;
        return sysfs_emit(buf, "%d\n", ret);
}

/*
 * set timer entry:
 *    auto - enable auto mode
 *    off - disable auto mode
 *    (other values) - reset chip timer
 */
static ssize_t bq2415x_sysfs_set_timer(struct device *dev,
                                       struct device_attribute *attr,
                                       const char *buf,
                                       size_t count)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        int ret = 0;

        if (strncmp(buf, "auto", 4) == 0)
                bq2415x_set_autotimer(bq, 1);
        else if (strncmp(buf, "off", 3) == 0)
                bq2415x_set_autotimer(bq, 0);
        else
                ret = bq2415x_exec_command(bq, BQ2415X_TIMER_RESET);

        if (ret < 0)
                return ret;
        return count;
}

/* show timer entry (auto or off) */
static ssize_t bq2415x_sysfs_show_timer(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);

        if (bq->timer_error)
                return sysfs_emit(buf, "%s\n", bq->timer_error);

        if (bq->autotimer)
                return sysfs_emit(buf, "auto\n");
        return sysfs_emit(buf, "off\n");
}

/*
 * set mode entry:
 *    auto - if automode is supported, enable it and set mode to reported
 *    none - disable charger and boost mode
 *    host - charging mode for host/hub chargers (current limit 500mA)
 *    dedicated - charging mode for dedicated chargers (unlimited current limit)
 *    boost - disable charger and enable boost mode
 */
static ssize_t bq2415x_sysfs_set_mode(struct device *dev,
                                      struct device_attribute *attr,
                                      const char *buf,
                                      size_t count)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        enum bq2415x_mode mode;
        int ret = 0;

        if (strncmp(buf, "auto", 4) == 0) {
                if (bq->automode < 0)
                        return -EINVAL;
                bq->automode = 1;
                mode = bq->reported_mode;
        } else if (strncmp(buf, "off", 3) == 0) {
                if (bq->automode > 0)
                        bq->automode = 0;
                mode = BQ2415X_MODE_OFF;
        } else if (strncmp(buf, "none", 4) == 0) {
                if (bq->automode > 0)
                        bq->automode = 0;
                mode = BQ2415X_MODE_NONE;
        } else if (strncmp(buf, "host", 4) == 0) {
                if (bq->automode > 0)
                        bq->automode = 0;
                mode = BQ2415X_MODE_HOST_CHARGER;
        } else if (strncmp(buf, "dedicated", 9) == 0) {
                if (bq->automode > 0)
                        bq->automode = 0;
                mode = BQ2415X_MODE_DEDICATED_CHARGER;
        } else if (strncmp(buf, "boost", 5) == 0) {
                if (bq->automode > 0)
                        bq->automode = 0;
                mode = BQ2415X_MODE_BOOST;
        } else if (strncmp(buf, "reset", 5) == 0) {
                bq2415x_reset_chip(bq);
                bq2415x_set_defaults(bq);
                if (bq->automode <= 0)
                        return count;
                bq->automode = 1;
                mode = bq->reported_mode;
        } else {
                return -EINVAL;
        }

        ret = bq2415x_set_mode(bq, mode);
        if (ret < 0)
                return ret;
        return count;
}

/* show mode entry (auto, none, host, dedicated or boost) */
static ssize_t bq2415x_sysfs_show_mode(struct device *dev,
                                       struct device_attribute *attr,
                                       char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        ssize_t ret = 0;

        if (bq->automode > 0)
                ret += sysfs_emit_at(buf, ret, "auto (");

        switch (bq->mode) {
        case BQ2415X_MODE_OFF:
                ret += sysfs_emit_at(buf, ret, "off");
                break;
        case BQ2415X_MODE_NONE:
                ret += sysfs_emit_at(buf, ret, "none");
                break;
        case BQ2415X_MODE_HOST_CHARGER:
                ret += sysfs_emit_at(buf, ret, "host");
                break;
        case BQ2415X_MODE_DEDICATED_CHARGER:
                ret += sysfs_emit_at(buf, ret, "dedicated");
                break;
        case BQ2415X_MODE_BOOST:
                ret += sysfs_emit_at(buf, ret, "boost");
                break;
        }

        if (bq->automode > 0)
                ret += sysfs_emit_at(buf, ret, ")");

        ret += sysfs_emit_at(buf, ret, "\n");
        return ret;
}

/* show reported_mode entry (none, host, dedicated or boost) */
static ssize_t bq2415x_sysfs_show_reported_mode(struct device *dev,
                                                struct device_attribute *attr,
                                                char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);

        if (bq->automode < 0)
                return -EINVAL;

        switch (bq->reported_mode) {
        case BQ2415X_MODE_OFF:
                return sysfs_emit(buf, "off\n");
        case BQ2415X_MODE_NONE:
                return sysfs_emit(buf, "none\n");
        case BQ2415X_MODE_HOST_CHARGER:
                return sysfs_emit(buf, "host\n");
        case BQ2415X_MODE_DEDICATED_CHARGER:
                return sysfs_emit(buf, "dedicated\n");
        case BQ2415X_MODE_BOOST:
                return sysfs_emit(buf, "boost\n");
        }

        return -EINVAL;
}

/* directly set raw value to chip register, format: 'register value' */
static ssize_t bq2415x_sysfs_set_registers(struct device *dev,
                                           struct device_attribute *attr,
                                           const char *buf,
                                           size_t count)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        ssize_t ret = 0;
        unsigned int reg;
        unsigned int val;

        if (sscanf(buf, "%x %x", &reg, &val) != 2)
                return -EINVAL;

        if (reg > 4 || val > 255)
                return -EINVAL;

        ret = bq2415x_i2c_write(bq, reg, val);
        if (ret < 0)
                return ret;
        return count;
}

/* print value of chip register, format: 'register=value' */
static ssize_t bq2415x_sysfs_print_reg(struct bq2415x_device *bq,
                                       u8 reg,
                                       char *buf)
{
        int ret = bq2415x_i2c_read(bq, reg);

        if (ret < 0)
                return sysfs_emit(buf, "%#.2x=error %d\n", reg, ret);
        return sysfs_emit(buf, "%#.2x=%#.2x\n", reg, ret);
}

/* show all raw values of chip register, format per line: 'register=value' */
static ssize_t bq2415x_sysfs_show_registers(struct device *dev,
                                            struct device_attribute *attr,
                                            char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        ssize_t ret = 0;

        ret += bq2415x_sysfs_print_reg(bq, BQ2415X_REG_STATUS, buf+ret);
        ret += bq2415x_sysfs_print_reg(bq, BQ2415X_REG_CONTROL, buf+ret);
        ret += bq2415x_sysfs_print_reg(bq, BQ2415X_REG_VOLTAGE, buf+ret);
        ret += bq2415x_sysfs_print_reg(bq, BQ2415X_REG_VENDER, buf+ret);
        ret += bq2415x_sysfs_print_reg(bq, BQ2415X_REG_CURRENT, buf+ret);
        return ret;
}

/* set current and voltage limit entries (in mA or mV) */
static ssize_t bq2415x_sysfs_set_limit(struct device *dev,
                                       struct device_attribute *attr,
                                       const char *buf,
                                       size_t count)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        long val;
        int ret;

        if (kstrtol(buf, 10, &val) < 0)
                return -EINVAL;

        if (strcmp(attr->attr.name, "current_limit") == 0)
                ret = bq2415x_set_current_limit(bq, val);
        else if (strcmp(attr->attr.name, "weak_battery_voltage") == 0)
                ret = bq2415x_set_weak_battery_voltage(bq, val);
        else if (strcmp(attr->attr.name, "battery_regulation_voltage") == 0)
                ret = bq2415x_set_battery_regulation_voltage(bq, val);
        else if (strcmp(attr->attr.name, "charge_current") == 0)
                ret = bq2415x_set_charge_current(bq, val);
        else if (strcmp(attr->attr.name, "termination_current") == 0)
                ret = bq2415x_set_termination_current(bq, val);
        else
                return -EINVAL;

        if (ret < 0)
                return ret;
        return count;
}

/* show current and voltage limit entries (in mA or mV) */
static ssize_t bq2415x_sysfs_show_limit(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        int ret;

        if (strcmp(attr->attr.name, "current_limit") == 0)
                ret = bq2415x_get_current_limit(bq);
        else if (strcmp(attr->attr.name, "weak_battery_voltage") == 0)
                ret = bq2415x_get_weak_battery_voltage(bq);
        else if (strcmp(attr->attr.name, "battery_regulation_voltage") == 0)
                ret = bq2415x_get_battery_regulation_voltage(bq);
        else if (strcmp(attr->attr.name, "charge_current") == 0)
                ret = bq2415x_get_charge_current(bq);
        else if (strcmp(attr->attr.name, "termination_current") == 0)
                ret = bq2415x_get_termination_current(bq);
        else
                return -EINVAL;

        if (ret < 0)
                return ret;
        return sysfs_emit(buf, "%d\n", ret);
}

/* set *_enable entries */
static ssize_t bq2415x_sysfs_set_enable(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf,
                                        size_t count)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        enum bq2415x_command command;
        long val;
        int ret;

        if (kstrtol(buf, 10, &val) < 0)
                return -EINVAL;

        if (strcmp(attr->attr.name, "charge_termination_enable") == 0)
                command = val ? BQ2415X_CHARGE_TERMINATION_ENABLE :
                        BQ2415X_CHARGE_TERMINATION_DISABLE;
        else if (strcmp(attr->attr.name, "high_impedance_enable") == 0)
                command = val ? BQ2415X_HIGH_IMPEDANCE_ENABLE :
                        BQ2415X_HIGH_IMPEDANCE_DISABLE;
        else if (strcmp(attr->attr.name, "otg_pin_enable") == 0)
                command = val ? BQ2415X_OTG_PIN_ENABLE :
                        BQ2415X_OTG_PIN_DISABLE;
        else if (strcmp(attr->attr.name, "stat_pin_enable") == 0)
                command = val ? BQ2415X_STAT_PIN_ENABLE :
                        BQ2415X_STAT_PIN_DISABLE;
        else
                return -EINVAL;

        ret = bq2415x_exec_command(bq, command);
        if (ret < 0)
                return ret;
        return count;
}

/* show *_enable entries */
static ssize_t bq2415x_sysfs_show_enable(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct power_supply *psy = dev_to_psy(dev);
        struct bq2415x_device *bq = power_supply_get_drvdata(psy);
        enum bq2415x_command command;
        int ret;

        if (strcmp(attr->attr.name, "charge_termination_enable") == 0)
                command = BQ2415X_CHARGE_TERMINATION_STATUS;
        else if (strcmp(attr->attr.name, "high_impedance_enable") == 0)
                command = BQ2415X_HIGH_IMPEDANCE_STATUS;
        else if (strcmp(attr->attr.name, "otg_pin_enable") == 0)
                command = BQ2415X_OTG_PIN_STATUS;
        else if (strcmp(attr->attr.name, "stat_pin_enable") == 0)
                command = BQ2415X_STAT_PIN_STATUS;
        else
                return -EINVAL;

        ret = bq2415x_exec_command(bq, command);
        if (ret < 0)
                return ret;
        return sysfs_emit(buf, "%d\n", ret);
}

static DEVICE_ATTR(current_limit, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_limit, bq2415x_sysfs_set_limit);
static DEVICE_ATTR(weak_battery_voltage, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_limit, bq2415x_sysfs_set_limit);
static DEVICE_ATTR(battery_regulation_voltage, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_limit, bq2415x_sysfs_set_limit);
static DEVICE_ATTR(charge_current, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_limit, bq2415x_sysfs_set_limit);
static DEVICE_ATTR(termination_current, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_limit, bq2415x_sysfs_set_limit);

static DEVICE_ATTR(charge_termination_enable, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_enable, bq2415x_sysfs_set_enable);
static DEVICE_ATTR(high_impedance_enable, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_enable, bq2415x_sysfs_set_enable);
static DEVICE_ATTR(otg_pin_enable, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_enable, bq2415x_sysfs_set_enable);
static DEVICE_ATTR(stat_pin_enable, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_enable, bq2415x_sysfs_set_enable);

static DEVICE_ATTR(reported_mode, S_IRUGO,
                bq2415x_sysfs_show_reported_mode, NULL);
static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_mode, bq2415x_sysfs_set_mode);
static DEVICE_ATTR(timer, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_timer, bq2415x_sysfs_set_timer);

static DEVICE_ATTR(registers, S_IWUSR | S_IRUGO,
                bq2415x_sysfs_show_registers, bq2415x_sysfs_set_registers);

static DEVICE_ATTR(otg_status, S_IRUGO, bq2415x_sysfs_show_status, NULL);
static DEVICE_ATTR(charge_status, S_IRUGO, bq2415x_sysfs_show_status, NULL);
static DEVICE_ATTR(boost_status, S_IRUGO, bq2415x_sysfs_show_status, NULL);
static DEVICE_ATTR(fault_status, S_IRUGO, bq2415x_sysfs_show_status, NULL);

static struct attribute *bq2415x_sysfs_attrs[] = {
        /*
         * TODO: some (appropriate) of these attrs should be switched to
         * use power supply class props.
         */
        &dev_attr_current_limit.attr,
        &dev_attr_weak_battery_voltage.attr,
        &dev_attr_battery_regulation_voltage.attr,
        &dev_attr_charge_current.attr,
        &dev_attr_termination_current.attr,

        &dev_attr_charge_termination_enable.attr,
        &dev_attr_high_impedance_enable.attr,
        &dev_attr_otg_pin_enable.attr,
        &dev_attr_stat_pin_enable.attr,

        &dev_attr_reported_mode.attr,
        &dev_attr_mode.attr,
        &dev_attr_timer.attr,

        &dev_attr_registers.attr,

        &dev_attr_otg_status.attr,
        &dev_attr_charge_status.attr,
        &dev_attr_boost_status.attr,
        &dev_attr_fault_status.attr,
        NULL,
};

ATTRIBUTE_GROUPS(bq2415x_sysfs);

static int bq2415x_power_supply_init(struct bq2415x_device *bq)
{
        int ret;
        int chip;
        char revstr[8];
        struct power_supply_config psy_cfg = {
                .drv_data = bq,
                .fwnode = dev_fwnode(bq->dev),
                .attr_grp = bq2415x_sysfs_groups,
        };

        bq->charger_desc.name = bq->name;
        bq->charger_desc.type = POWER_SUPPLY_TYPE_USB;
        bq->charger_desc.properties = bq2415x_power_supply_props;
        bq->charger_desc.num_properties =
                        ARRAY_SIZE(bq2415x_power_supply_props);
        bq->charger_desc.get_property = bq2415x_power_supply_get_property;

        ret = bq2415x_detect_chip(bq);
        if (ret < 0)
                chip = BQUNKNOWN;
        else
                chip = ret;

        ret = bq2415x_detect_revision(bq);
        if (ret < 0)
                strscpy(revstr, "unknown", sizeof(revstr));
        else
                sprintf(revstr, "1.%d", ret);

        bq->model = kasprintf(GFP_KERNEL,
                                "chip %s, revision %s, vender code %.3d",
                                bq2415x_chip_name[chip], revstr,
                                bq2415x_get_vender_code(bq));
        if (!bq->model) {
                dev_err(bq->dev, "failed to allocate model name\n");
                return -ENOMEM;
        }

        bq->charger = power_supply_register(bq->dev, &bq->charger_desc,
                                            &psy_cfg);
        if (IS_ERR(bq->charger)) {
                kfree(bq->model);
                return PTR_ERR(bq->charger);
        }

        return 0;
}

/* main bq2415x probe function */
static int bq2415x_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        int ret;
        int num;
        char *name = NULL;
        struct bq2415x_device *bq;
        struct device_node *np = client->dev.of_node;
        struct bq2415x_platform_data *pdata = client->dev.platform_data;
        const struct acpi_device_id *acpi_id = NULL;
        struct power_supply *notify_psy = NULL;
        union power_supply_propval prop;

        if (!np && !pdata && !ACPI_HANDLE(&client->dev)) {
                dev_err(&client->dev, "Neither devicetree, nor platform data, nor ACPI support\n");
                return -ENODEV;
        }

        /* Get new ID for the new device */
        mutex_lock(&bq2415x_id_mutex);
        num = idr_alloc(&bq2415x_id, client, 0, 0, GFP_KERNEL);
        mutex_unlock(&bq2415x_id_mutex);
        if (num < 0)
                return num;

        if (id) {
                name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
        } else if (ACPI_HANDLE(&client->dev)) {
                acpi_id =
                        acpi_match_device(client->dev.driver->acpi_match_table,
                                          &client->dev);
                if (!acpi_id) {
                        dev_err(&client->dev, "failed to match device name\n");
                        ret = -ENODEV;
                        goto error_1;
                }
                name = kasprintf(GFP_KERNEL, "%s-%d", acpi_id->id, num);
        }
        if (!name) {
                dev_err(&client->dev, "failed to allocate device name\n");
                ret = -ENOMEM;
                goto error_1;
        }

        bq = devm_kzalloc(&client->dev, sizeof(*bq), GFP_KERNEL);
        if (!bq) {
                ret = -ENOMEM;
                goto error_2;
        }

        i2c_set_clientdata(client, bq);

        bq->id = num;
        bq->dev = &client->dev;
        if (id)
                bq->chip = id->driver_data;
        else if (ACPI_HANDLE(bq->dev))
                bq->chip = acpi_id->driver_data;
        bq->name = name;
        bq->mode = BQ2415X_MODE_OFF;
        bq->reported_mode = BQ2415X_MODE_OFF;
        bq->autotimer = 0;
        bq->automode = 0;

        if (np || ACPI_HANDLE(bq->dev)) {
                ret = device_property_read_u32(bq->dev,
                                               "ti,current-limit",
                                               &bq->init_data.current_limit);
                if (ret)
                        goto error_2;
                ret = device_property_read_u32(bq->dev,
                                        "ti,weak-battery-voltage",
                                        &bq->init_data.weak_battery_voltage);
                if (ret)
                        goto error_2;
                ret = device_property_read_u32(bq->dev,
                                "ti,battery-regulation-voltage",
                                &bq->init_data.battery_regulation_voltage);
                if (ret)
                        goto error_2;
                ret = device_property_read_u32(bq->dev,
                                               "ti,charge-current",
                                               &bq->init_data.charge_current);
                if (ret)
                        goto error_2;
                ret = device_property_read_u32(bq->dev,
                                "ti,termination-current",
                                &bq->init_data.termination_current);
                if (ret)
                        goto error_2;
                ret = device_property_read_u32(bq->dev,
                                               "ti,resistor-sense",
                                               &bq->init_data.resistor_sense);
                if (ret)
                        goto error_2;
                if (np)
                        bq->notify_node = of_parse_phandle(np,
                                                "ti,usb-charger-detection", 0);
        } else {
                memcpy(&bq->init_data, pdata, sizeof(bq->init_data));
        }

        bq2415x_reset_chip(bq);

        ret = bq2415x_power_supply_init(bq);
        if (ret) {
                dev_err(bq->dev, "failed to register power supply: %d\n", ret);
                goto error_2;
        }

        ret = bq2415x_set_defaults(bq);
        if (ret) {
                dev_err(bq->dev, "failed to set default values: %d\n", ret);
                goto error_3;
        }

        if (bq->notify_node || bq->init_data.notify_device) {
                bq->nb.notifier_call = bq2415x_notifier_call;
                ret = power_supply_reg_notifier(&bq->nb);
                if (ret) {
                        dev_err(bq->dev, "failed to reg notifier: %d\n", ret);
                        goto error_3;
                }

                bq->automode = 1;
                dev_info(bq->dev, "automode supported, waiting for events\n");
        } else {
                bq->automode = -1;
                dev_info(bq->dev, "automode not supported\n");
        }

        /* Query for initial reported_mode and set it */
        if (bq->nb.notifier_call) {
                if (np) {
                        notify_psy = power_supply_get_by_reference(of_fwnode_handle(np),
                                                "ti,usb-charger-detection");
                        if (IS_ERR(notify_psy))
                                notify_psy = NULL;
                } else if (bq->init_data.notify_device) {
                        notify_psy = power_supply_get_by_name(
                                                bq->init_data.notify_device);
                }
        }
        if (notify_psy) {
                ret = power_supply_get_property(notify_psy,
                                        POWER_SUPPLY_PROP_CURRENT_MAX, &prop);
                power_supply_put(notify_psy);

                if (ret == 0) {
                        bq2415x_update_reported_mode(bq, prop.intval);
                        bq2415x_set_mode(bq, bq->reported_mode);
                }
        }

        INIT_DELAYED_WORK(&bq->work, bq2415x_timer_work);
        bq2415x_set_autotimer(bq, 1);

        dev_info(bq->dev, "driver registered\n");
        return 0;

error_3:
        bq2415x_power_supply_exit(bq);
error_2:
        if (bq)
                of_node_put(bq->notify_node);
        kfree(name);
error_1:
        mutex_lock(&bq2415x_id_mutex);
        idr_remove(&bq2415x_id, num);
        mutex_unlock(&bq2415x_id_mutex);

        return ret;
}

/* main bq2415x remove function */

static void bq2415x_remove(struct i2c_client *client)
{
        struct bq2415x_device *bq = i2c_get_clientdata(client);

        if (bq->nb.notifier_call)
                power_supply_unreg_notifier(&bq->nb);

        of_node_put(bq->notify_node);
        bq2415x_power_supply_exit(bq);

        bq2415x_reset_chip(bq);

        mutex_lock(&bq2415x_id_mutex);
        idr_remove(&bq2415x_id, bq->id);
        mutex_unlock(&bq2415x_id_mutex);

        dev_info(bq->dev, "driver unregistered\n");

        kfree(bq->name);
}

static const struct i2c_device_id bq2415x_i2c_id_table[] = {
        { "bq2415x", BQUNKNOWN },
        { "bq24150", BQ24150 },
        { "bq24150a", BQ24150A },
        { "bq24151", BQ24151 },
        { "bq24151a", BQ24151A },
        { "bq24152", BQ24152 },
        { "bq24153", BQ24153 },
        { "bq24153a", BQ24153A },
        { "bq24155", BQ24155 },
        { "bq24156", BQ24156 },
        { "bq24156a", BQ24156A },
        { "bq24157s", BQ24157S },
        { "bq24158", BQ24158 },
        {},
};
MODULE_DEVICE_TABLE(i2c, bq2415x_i2c_id_table);

#ifdef CONFIG_ACPI
static const struct acpi_device_id bq2415x_i2c_acpi_match[] = {
        { "BQ2415X", BQUNKNOWN },
        { "BQ241500", BQ24150 },
        { "BQA24150", BQ24150A },
        { "BQ241510", BQ24151 },
        { "BQA24151", BQ24151A },
        { "BQ241520", BQ24152 },
        { "BQ241530", BQ24153 },
        { "BQA24153", BQ24153A },
        { "BQ241550", BQ24155 },
        { "BQ241560", BQ24156 },
        { "BQA24156", BQ24156A },
        { "BQS24157", BQ24157S },
        { "BQ241580", BQ24158 },
        {},
};
MODULE_DEVICE_TABLE(acpi, bq2415x_i2c_acpi_match);
#endif

#ifdef CONFIG_OF
static const struct of_device_id bq2415x_of_match_table[] = {
        { .compatible = "ti,bq24150" },
        { .compatible = "ti,bq24150a" },
        { .compatible = "ti,bq24151" },
        { .compatible = "ti,bq24151a" },
        { .compatible = "ti,bq24152" },
        { .compatible = "ti,bq24153" },
        { .compatible = "ti,bq24153a" },
        { .compatible = "ti,bq24155" },
        { .compatible = "ti,bq24156" },
        { .compatible = "ti,bq24156a" },
        { .compatible = "ti,bq24157s" },
        { .compatible = "ti,bq24158" },
        {},
};
MODULE_DEVICE_TABLE(of, bq2415x_of_match_table);
#endif

static struct i2c_driver bq2415x_driver = {
        .driver = {
                .name = "bq2415x-charger",
                .of_match_table = of_match_ptr(bq2415x_of_match_table),
                .acpi_match_table = ACPI_PTR(bq2415x_i2c_acpi_match),
        },
        .probe = bq2415x_probe,
        .remove = bq2415x_remove,
        .id_table = bq2415x_i2c_id_table,
};
module_i2c_driver(bq2415x_driver);

MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
MODULE_DESCRIPTION("bq2415x charger driver");
MODULE_LICENSE("GPL");