// SPDX-License-Identifier: GPL-2.0-only
/*
 * ROHM BD99954 charger driver
 *
 * Copyright (C) 2020 Rohm Semiconductors
 *      Originally written by:
 *              Mikko Mutanen <mikko.mutanen@fi.rohmeurope.com>
 *              Markus Laine <markus.laine@fi.rohmeurope.com>
 *      Bugs added by:
 *              Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
 */

/*
 *   The battery charging profile of BD99954.
 *
 *   Curve (1) represents charging current.
 *   Curve (2) represents battery voltage.
 *
 *   The BD99954 data sheet divides charging to three phases.
 *   a) Trickle-charge with constant current (8).
 *   b) pre-charge with constant current (6)
 *   c) fast-charge, first with constant current (5) phase. After
 *      the battery voltage has reached target level (4) we have constant
 *      voltage phase until charging current has dropped to termination
 *      level (7)
 *
 *    V ^                                                        ^ I
 *      .                                                        .
 *      .                                                        .
 *(4)` `.` ` ` ` ` ` ` ` ` ` ` ` ` ` ----------------------------.
 *      .                           :/                           .
 *      .                     o----+/:/ ` ` ` ` ` ` ` ` ` ` ` ` `.` ` (5)
 *      .                     +   ::  +                          .
 *      .                     +  /-   --                         .
 *      .                     +`/-     +                         .
 *      .                     o/-      -:                        .
 *      .                    .s.        +`                       .
 *      .                  .--+         `/                       .
 *      .               ..``  +          .:                      .
 *      .             -`      +           --                     .
 *      .    (2)  ...``       +            :-                    .
 *      .    ...``            +             -:                   .
 *(3)` `.`.""  ` ` ` `+-------- ` ` ` ` ` ` `.:` ` ` ` ` ` ` ` ` .` ` (6)
 *      .             +                       `:.                .
 *      .             +                         -:               .
 *      .             +                           -:.            .
 *      .             +                             .--.         .
 *      .   (1)       +                                `.+` ` ` `.` ` (7)
 *      -..............` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` + ` ` ` .` ` (8)
 *      .                                                +       -
 *      -------------------------------------------------+++++++++-->
 *      |   trickle   |  pre  |          fast            |
 *
 * Details of DT properties for different limits can be found from BD99954
 * device tree binding documentation.
 */

#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/linear_range.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/power_supply.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/types.h>

#include "bd99954-charger.h"

/* Initial field values, converted to initial register values */
struct bd9995x_init_data {
        u16 vsysreg_set;        /* VSYS Regulation Setting */
        u16 ibus_lim_set;       /* VBUS input current limitation */
        u16 icc_lim_set;        /* VCC/VACP Input Current Limit Setting */
        u16 itrich_set;         /* Trickle-charge Current Setting */
        u16 iprech_set;         /* Pre-Charge Current Setting */
        u16 ichg_set;           /* Fast-Charge constant current */
        u16 vfastchg_reg_set1;  /* Fast Charging Regulation Voltage */
        u16 vprechg_th_set;     /* Pre-charge Voltage Threshold Setting */
        u16 vrechg_set;         /* Re-charge Battery Voltage Setting */
        u16 vbatovp_set;        /* Battery Over Voltage Threshold Setting */
        u16 iterm_set;          /* Charging termination current */
};

struct bd9995x_state {
        u8 online;
        u16 chgstm_status;
        u16 vbat_vsys_status;
        u16 vbus_vcc_status;
};

struct bd9995x_device {
        struct i2c_client *client;
        struct device *dev;
        struct power_supply *charger;

        struct regmap *rmap;
        struct regmap_field *rmap_fields[F_MAX_FIELDS];

        int chip_id;
        int chip_rev;
        struct bd9995x_init_data init_data;
        struct bd9995x_state state;

        struct mutex lock; /* Protect state data */
};

static const struct regmap_range bd9995x_readonly_reg_ranges[] = {
        regmap_reg_range(CHGSTM_STATUS, SEL_ILIM_VAL),
        regmap_reg_range(IOUT_DACIN_VAL, IOUT_DACIN_VAL),
        regmap_reg_range(VCC_UCD_STATUS, VCC_IDD_STATUS),
        regmap_reg_range(VBUS_UCD_STATUS, VBUS_IDD_STATUS),
        regmap_reg_range(CHIP_ID, CHIP_REV),
        regmap_reg_range(SYSTEM_STATUS, SYSTEM_STATUS),
        regmap_reg_range(IBATP_VAL, VBAT_AVE_VAL),
        regmap_reg_range(VTH_VAL, EXTIADP_AVE_VAL),
};

static const struct regmap_access_table bd9995x_writeable_regs = {
        .no_ranges = bd9995x_readonly_reg_ranges,
        .n_no_ranges = ARRAY_SIZE(bd9995x_readonly_reg_ranges),
};

static const struct regmap_range bd9995x_volatile_reg_ranges[] = {
        regmap_reg_range(CHGSTM_STATUS, WDT_STATUS),
        regmap_reg_range(VCC_UCD_STATUS, VCC_IDD_STATUS),
        regmap_reg_range(VBUS_UCD_STATUS, VBUS_IDD_STATUS),
        regmap_reg_range(INT0_STATUS, INT7_STATUS),
        regmap_reg_range(SYSTEM_STATUS, SYSTEM_CTRL_SET),
        regmap_reg_range(IBATP_VAL, EXTIADP_AVE_VAL), /* Measurement regs */
};

static const struct regmap_access_table bd9995x_volatile_regs = {
        .yes_ranges = bd9995x_volatile_reg_ranges,
        .n_yes_ranges = ARRAY_SIZE(bd9995x_volatile_reg_ranges),
};

static const struct regmap_range_cfg regmap_range_cfg[] = {
        {
        .selector_reg     = MAP_SET,
        .selector_mask    = 0xFFFF,
        .selector_shift   = 0,
        .window_start     = 0,
        .window_len       = 0x100,
        .range_min        = 0 * 0x100,
        .range_max        = 3 * 0x100,
        },
};

static const struct regmap_config bd9995x_regmap_config = {
        .reg_bits = 8,
        .val_bits = 16,
        .reg_stride = 1,

        .max_register = 3 * 0x100,
        .cache_type = REGCACHE_MAPLE,

        .ranges = regmap_range_cfg,
        .num_ranges = ARRAY_SIZE(regmap_range_cfg),
        .val_format_endian = REGMAP_ENDIAN_LITTLE,
        .wr_table = &bd9995x_writeable_regs,
        .volatile_table = &bd9995x_volatile_regs,
};

enum bd9995x_chrg_fault {
        CHRG_FAULT_NORMAL,
        CHRG_FAULT_INPUT,
        CHRG_FAULT_THERMAL_SHUTDOWN,
        CHRG_FAULT_TIMER_EXPIRED,
};

static int bd9995x_get_prop_batt_health(struct bd9995x_device *bd)
{
        int ret, tmp;

        ret = regmap_field_read(bd->rmap_fields[F_BATTEMP], &tmp);
        if (ret)
                return POWER_SUPPLY_HEALTH_UNKNOWN;

        /* TODO: Check these against datasheet page 34 */

        switch (tmp) {
        case ROOM:
                return POWER_SUPPLY_HEALTH_GOOD;
        case HOT1:
        case HOT2:
        case HOT3:
                return POWER_SUPPLY_HEALTH_OVERHEAT;
        case COLD1:
        case COLD2:
                return POWER_SUPPLY_HEALTH_COLD;
        case TEMP_DIS:
        case BATT_OPEN:
        default:
                return POWER_SUPPLY_HEALTH_UNKNOWN;
        }
}

static int bd9995x_get_prop_charge_type(struct bd9995x_device *bd)
{
        int ret, tmp;

        ret = regmap_field_read(bd->rmap_fields[F_CHGSTM_STATE], &tmp);
        if (ret)
                return POWER_SUPPLY_CHARGE_TYPE_UNKNOWN;

        switch (tmp) {
        case CHGSTM_TRICKLE_CHARGE:
        case CHGSTM_PRE_CHARGE:
                return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
        case CHGSTM_FAST_CHARGE:
                return POWER_SUPPLY_CHARGE_TYPE_FAST;
        case CHGSTM_TOP_OFF:
        case CHGSTM_DONE:
        case CHGSTM_SUSPEND:
                return POWER_SUPPLY_CHARGE_TYPE_NONE;
        default: /* Rest of the states are error related, no charging */
                return POWER_SUPPLY_CHARGE_TYPE_NONE;
        }
}

static bool bd9995x_get_prop_batt_present(struct bd9995x_device *bd)
{
        int ret, tmp;

        ret = regmap_field_read(bd->rmap_fields[F_BATTEMP], &tmp);
        if (ret)
                return false;

        return tmp != BATT_OPEN;
}

static int bd9995x_get_prop_batt_voltage(struct bd9995x_device *bd)
{
        int ret, tmp;

        ret = regmap_field_read(bd->rmap_fields[F_VBAT_VAL], &tmp);
        if (ret)
                return 0;

        tmp = min(tmp, 19200);

        return tmp * 1000;
}

static int bd9995x_get_prop_batt_current(struct bd9995x_device *bd)
{
        int ret, tmp;

        ret = regmap_field_read(bd->rmap_fields[F_IBATP_VAL], &tmp);
        if (ret)
                return 0;

        return tmp * 1000;
}

#define DEFAULT_BATTERY_TEMPERATURE 250

static int bd9995x_get_prop_batt_temp(struct bd9995x_device *bd)
{
        int ret, tmp;

        ret = regmap_field_read(bd->rmap_fields[F_THERM_VAL], &tmp);
        if (ret)
                return DEFAULT_BATTERY_TEMPERATURE;

        return (200 - tmp) * 10;
}

static int bd9995x_power_supply_get_property(struct power_supply *psy,
                                             enum power_supply_property psp,
                                             union power_supply_propval *val)
{
        int ret, tmp;
        struct bd9995x_device *bd = power_supply_get_drvdata(psy);
        struct bd9995x_state state;

        mutex_lock(&bd->lock);
        state = bd->state;
        mutex_unlock(&bd->lock);

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                switch (state.chgstm_status) {
                case CHGSTM_TRICKLE_CHARGE:
                case CHGSTM_PRE_CHARGE:
                case CHGSTM_FAST_CHARGE:
                case CHGSTM_TOP_OFF:
                        val->intval = POWER_SUPPLY_STATUS_CHARGING;
                        break;

                case CHGSTM_DONE:
                        val->intval = POWER_SUPPLY_STATUS_FULL;
                        break;

                case CHGSTM_SUSPEND:
                case CHGSTM_TEMPERATURE_ERROR_1:
                case CHGSTM_TEMPERATURE_ERROR_2:
                case CHGSTM_TEMPERATURE_ERROR_3:
                case CHGSTM_TEMPERATURE_ERROR_4:
                case CHGSTM_TEMPERATURE_ERROR_5:
                case CHGSTM_TEMPERATURE_ERROR_6:
                case CHGSTM_TEMPERATURE_ERROR_7:
                case CHGSTM_THERMAL_SHUT_DOWN_1:
                case CHGSTM_THERMAL_SHUT_DOWN_2:
                case CHGSTM_THERMAL_SHUT_DOWN_3:
                case CHGSTM_THERMAL_SHUT_DOWN_4:
                case CHGSTM_THERMAL_SHUT_DOWN_5:
                case CHGSTM_THERMAL_SHUT_DOWN_6:
                case CHGSTM_THERMAL_SHUT_DOWN_7:
                case CHGSTM_BATTERY_ERROR:
                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                        break;

                default:
                        val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
                        break;
                }
                break;

        case POWER_SUPPLY_PROP_MANUFACTURER:
                val->strval = BD9995X_MANUFACTURER;
                break;

        case POWER_SUPPLY_PROP_ONLINE:
                val->intval = state.online;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
                ret = regmap_field_read(bd->rmap_fields[F_IBATP_VAL], &tmp);
                if (ret)
                        return ret;
                val->intval = tmp * 1000;
                break;

        case POWER_SUPPLY_PROP_CHARGE_AVG:
                ret = regmap_field_read(bd->rmap_fields[F_IBATP_AVE_VAL], &tmp);
                if (ret)
                        return ret;
                val->intval = tmp * 1000;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
                /*
                 * Currently the DT uses this property to give the
                 * target current for fast-charging constant current phase.
                 * I think it is correct in a sense.
                 *
                 * Yet, this prop we read and return here is the programmed
                 * safety limit for combined input currents. This feels
                 * also correct in a sense.
                 *
                 * However, this results a mismatch to DT value and value
                 * read from sysfs.
                 */
                ret = regmap_field_read(bd->rmap_fields[F_SEL_ILIM_VAL], &tmp);
                if (ret)
                        return ret;
                val->intval = tmp * 1000;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                if (!state.online) {
                        val->intval = 0;
                        break;
                }

                ret = regmap_field_read(bd->rmap_fields[F_VFASTCHG_REG_SET1],
                                        &tmp);
                if (ret)
                        return ret;

                /*
                 * The actual range : 2560 to 19200 mV. No matter what the
                 * register says
                 */
                val->intval = clamp_val(tmp << 4, 2560, 19200);
                val->intval *= 1000;
                break;

        case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
                ret = regmap_field_read(bd->rmap_fields[F_ITERM_SET], &tmp);
                if (ret)
                        return ret;
                /* Start step is 64 mA */
                val->intval = tmp << 6;
                /* Maximum is 1024 mA - no matter what register says */
                val->intval = min(val->intval, 1024);
                val->intval *= 1000;
                break;

        /* Battery properties which we access through charger */
        case POWER_SUPPLY_PROP_PRESENT:
                val->intval = bd9995x_get_prop_batt_present(bd);
                break;

        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                val->intval = bd9995x_get_prop_batt_voltage(bd);
                break;

        case POWER_SUPPLY_PROP_CURRENT_NOW:
                val->intval = bd9995x_get_prop_batt_current(bd);
                break;

        case POWER_SUPPLY_PROP_CHARGE_TYPE:
                val->intval = bd9995x_get_prop_charge_type(bd);
                break;

        case POWER_SUPPLY_PROP_HEALTH:
                val->intval = bd9995x_get_prop_batt_health(bd);
                break;

        case POWER_SUPPLY_PROP_TEMP:
                val->intval = bd9995x_get_prop_batt_temp(bd);
                break;

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

        case POWER_SUPPLY_PROP_MODEL_NAME:
                val->strval = "bd99954";
                break;

        default:
                return -EINVAL;

        }

        return 0;
}

static int bd9995x_get_chip_state(struct bd9995x_device *bd,
                                  struct bd9995x_state *state)
{
        int i, ret, tmp;
        struct {
                struct regmap_field *id;
                u16 *data;
        } state_fields[] = {
                {
                        bd->rmap_fields[F_CHGSTM_STATE], &state->chgstm_status,
                }, {
                        bd->rmap_fields[F_VBAT_VSYS_STATUS],
                        &state->vbat_vsys_status,
                }, {
                        bd->rmap_fields[F_VBUS_VCC_STATUS],
                        &state->vbus_vcc_status,
                },
        };


        for (i = 0; i < ARRAY_SIZE(state_fields); i++) {
                ret = regmap_field_read(state_fields[i].id, &tmp);
                if (ret)
                        return ret;

                *state_fields[i].data = tmp;
        }

        if (state->vbus_vcc_status & STATUS_VCC_DET ||
            state->vbus_vcc_status & STATUS_VBUS_DET)
                state->online = 1;
        else
                state->online = 0;

        return 0;
}

static irqreturn_t bd9995x_irq_handler_thread(int irq, void *private)
{
        struct bd9995x_device *bd = private;
        int ret, status, mask, i;
        unsigned long tmp;
        struct bd9995x_state state;

        /*
         * The bd9995x does not seem to generate big amount of interrupts.
         * The logic regarding which interrupts can cause relevant
         * status changes seem to be pretty complex.
         *
         * So lets implement really simple and hopefully bullet-proof handler:
         * It does not really matter which IRQ we handle, we just go and
         * re-read all interesting statuses + give the framework a nudge.
         *
         * Other option would be building a _complex_ and error prone logic
         * trying to decide what could have been changed (resulting this IRQ
         * we are now handling). During the normal operation the BD99954 does
         * not seem to be generating much of interrupts so benefit from such
         * logic would probably be minimal.
         */

        ret = regmap_read(bd->rmap, INT0_STATUS, &status);
        if (ret) {
                dev_err(bd->dev, "Failed to read IRQ status\n");
                return IRQ_NONE;
        }

        ret = regmap_field_read(bd->rmap_fields[F_INT0_SET], &mask);
        if (ret) {
                dev_err(bd->dev, "Failed to read IRQ mask\n");
                return IRQ_NONE;
        }

        /* Handle only IRQs that are not masked */
        status &= mask;
        tmp = status;

        /* Lowest bit does not represent any sub-registers */
        tmp >>= 1;

        /*
         * Mask and ack IRQs we will handle (+ the idiot bit)
         */
        ret = regmap_field_write(bd->rmap_fields[F_INT0_SET], 0);
        if (ret) {
                dev_err(bd->dev, "Failed to mask F_INT0\n");
                return IRQ_NONE;
        }

        ret = regmap_write(bd->rmap, INT0_STATUS, status);
        if (ret) {
                dev_err(bd->dev, "Failed to ack F_INT0\n");
                goto err_umask;
        }

        for_each_set_bit(i, &tmp, 7) {
                int sub_status, sub_mask;
                static const int sub_status_reg[] = {
                        INT1_STATUS, INT2_STATUS, INT3_STATUS, INT4_STATUS,
                        INT5_STATUS, INT6_STATUS, INT7_STATUS,
                };
                struct regmap_field *sub_mask_f[] = {
                        bd->rmap_fields[F_INT1_SET],
                        bd->rmap_fields[F_INT2_SET],
                        bd->rmap_fields[F_INT3_SET],
                        bd->rmap_fields[F_INT4_SET],
                        bd->rmap_fields[F_INT5_SET],
                        bd->rmap_fields[F_INT6_SET],
                        bd->rmap_fields[F_INT7_SET],
                };

                /* Clear sub IRQs */
                ret = regmap_read(bd->rmap, sub_status_reg[i], &sub_status);
                if (ret) {
                        dev_err(bd->dev, "Failed to read IRQ sub-status\n");
                        goto err_umask;
                }

                ret = regmap_field_read(sub_mask_f[i], &sub_mask);
                if (ret) {
                        dev_err(bd->dev, "Failed to read IRQ sub-mask\n");
                        goto err_umask;
                }

                /* Ack active sub-statuses */
                sub_status &= sub_mask;

                ret = regmap_write(bd->rmap, sub_status_reg[i], sub_status);
                if (ret) {
                        dev_err(bd->dev, "Failed to ack sub-IRQ\n");
                        goto err_umask;
                }
        }

        ret = regmap_field_write(bd->rmap_fields[F_INT0_SET], mask);
        if (ret)
                /* May as well retry once */
                goto err_umask;

        /* Read whole chip state */
        ret = bd9995x_get_chip_state(bd, &state);
        if (ret < 0) {
                dev_err(bd->dev, "Failed to read chip state\n");
        } else {
                mutex_lock(&bd->lock);
                bd->state = state;
                mutex_unlock(&bd->lock);

                power_supply_changed(bd->charger);
        }

        return IRQ_HANDLED;

err_umask:
        ret = regmap_field_write(bd->rmap_fields[F_INT0_SET], mask);
        if (ret)
                dev_err(bd->dev,
                "Failed to un-mask F_INT0 - IRQ permanently disabled\n");

        return IRQ_NONE;
}

static int __bd9995x_chip_reset(struct bd9995x_device *bd)
{
        int ret, state;
        int rst_check_counter = 10;
        u16 tmp = ALLRST | OTPLD;

        ret = regmap_raw_write(bd->rmap, SYSTEM_CTRL_SET, &tmp, 2);
        if (ret < 0)
                return ret;

        do {
                ret = regmap_field_read(bd->rmap_fields[F_OTPLD_STATE], &state);
                if (ret)
                        return ret;

                msleep(10);
        } while (state == 0 && --rst_check_counter);

        if (!rst_check_counter) {
                dev_err(bd->dev, "chip reset not completed\n");
                return -ETIMEDOUT;
        }

        tmp = 0;
        ret = regmap_raw_write(bd->rmap, SYSTEM_CTRL_SET, &tmp, 2);

        return ret;
}

static int bd9995x_hw_init(struct bd9995x_device *bd)
{
        int ret;
        int i;
        struct bd9995x_state state;
        struct bd9995x_init_data *id = &bd->init_data;

        const struct {
                enum bd9995x_fields id;
                u16 value;
        } init_data[] = {
                /* Enable the charging trigger after SDP charger attached */
                {F_SDP_CHG_TRIG_EN,     1},
                /* Enable charging trigger after SDP charger attached */
                {F_SDP_CHG_TRIG,        1},
                /* Disable charging trigger by BC1.2 detection */
                {F_VBUS_BC_DISEN,       1},
                /* Disable charging trigger by BC1.2 detection */
                {F_VCC_BC_DISEN,        1},
                /* Disable automatic limitation of the input current */
                {F_ILIM_AUTO_DISEN,     1},
                /* Select current limitation when SDP charger attached*/
                {F_SDP_500_SEL,         1},
                /* Select current limitation when DCP charger attached */
                {F_DCP_2500_SEL,        1},
                {F_VSYSREG_SET,         id->vsysreg_set},
                /* Activate USB charging and DC/DC converter */
                {F_USB_SUS,             0},
                /* DCDC clock: 1200 kHz*/
                {F_DCDC_CLK_SEL,        3},
                /* Enable charging */
                {F_CHG_EN,              1},
                /* Disable Input current Limit setting voltage measurement */
                {F_EXTIADPEN,           0},
                /* Disable input current limiting */
                {F_VSYS_PRIORITY,       1},
                {F_IBUS_LIM_SET,        id->ibus_lim_set},
                {F_ICC_LIM_SET,         id->icc_lim_set},
                /* Charge Termination Current Setting to 0*/
                {F_ITERM_SET,           id->iterm_set},
                /* Trickle-charge Current Setting */
                {F_ITRICH_SET,          id->itrich_set},
                /* Pre-charge Current setting */
                {F_IPRECH_SET,          id->iprech_set},
                /* Fast Charge Current for constant current phase */
                {F_ICHG_SET,            id->ichg_set},
                /* Fast Charge Voltage Regulation Setting */
                {F_VFASTCHG_REG_SET1,   id->vfastchg_reg_set1},
                /* Set Pre-charge Voltage Threshold for trickle charging. */
                {F_VPRECHG_TH_SET,      id->vprechg_th_set},
                {F_VRECHG_SET,          id->vrechg_set},
                {F_VBATOVP_SET,         id->vbatovp_set},
                /* Reverse buck boost voltage Setting */
                {F_VRBOOST_SET,         0},
                /* Disable fast-charging watchdog */
                {F_WDT_FST,             0},
                /* Disable pre-charging watchdog */
                {F_WDT_PRE,             0},
                /* Power save off */
                {F_POWER_SAVE_MODE,     0},
                {F_INT1_SET,            INT1_ALL},
                {F_INT2_SET,            INT2_ALL},
                {F_INT3_SET,            INT3_ALL},
                {F_INT4_SET,            INT4_ALL},
                {F_INT5_SET,            INT5_ALL},
                {F_INT6_SET,            INT6_ALL},
                {F_INT7_SET,            INT7_ALL},
        };

        /*
         * Currently we initialize charger to a known state at startup.
         * If we want to allow for example the boot code to initialize
         * charger we should get rid of this.
         */
        ret = __bd9995x_chip_reset(bd);
        if (ret < 0)
                return ret;

        /* Initialize currents/voltages and other parameters */
        for (i = 0; i < ARRAY_SIZE(init_data); i++) {
                ret = regmap_field_write(bd->rmap_fields[init_data[i].id],
                                         init_data[i].value);
                if (ret) {
                        dev_err(bd->dev, "failed to initialize charger (%d)\n",
                                ret);
                        return ret;
                }
        }

        ret = bd9995x_get_chip_state(bd, &state);
        if (ret < 0)
                return ret;

        mutex_lock(&bd->lock);
        bd->state = state;
        mutex_unlock(&bd->lock);

        return 0;
}

static enum power_supply_property bd9995x_power_supply_props[] = {
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
        POWER_SUPPLY_PROP_CHARGE_AVG,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
        POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
        /* Battery props we access through charger */
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CHARGE_TYPE,
        POWER_SUPPLY_PROP_HEALTH,
        POWER_SUPPLY_PROP_TEMP,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_MODEL_NAME,
};

static const struct power_supply_desc bd9995x_power_supply_desc = {
        .name = "bd9995x-charger",
        .type = POWER_SUPPLY_TYPE_USB,
        .properties = bd9995x_power_supply_props,
        .num_properties = ARRAY_SIZE(bd9995x_power_supply_props),
        .get_property = bd9995x_power_supply_get_property,
};

/*
 * Limit configurations for vbus-input-current and vcc-vacp-input-current
 * Minimum limit is 0 uA. Max is 511 * 32000 uA = 16352000 uA. This is
 * configured by writing a register so that each increment in register
 * value equals to 32000 uA limit increment.
 *
 * Eg, value 0x0 is limit 0, value 0x1 is limit 32000, ...
 * Describe the setting in linear_range table.
 */
static const struct linear_range input_current_limit_ranges[] = {
        LINEAR_RANGE(0, 0x0, 0x1ff, 32000),
};

/* Possible trickle, pre-charging and termination current values */
static const struct linear_range charging_current_ranges[] = {
        LINEAR_RANGE(0, 0x0, 0x10, 64000),
        LINEAR_RANGE(1024000, 0x11, 0x1f, 0),
};

/*
 * Fast charging voltage regulation, starting re-charging limit
 * and battery over voltage protection have same possible values
 */
static const struct linear_range charge_voltage_regulation_ranges[] = {
        LINEAR_RANGE(2560000, 0, 0xA0, 0),
        LINEAR_RANGE(2560000, 0xA0, 0x4B0, 16000),
        LINEAR_RANGE(19200000, 0x4B0, 0x7FF, 0),
};

/* Possible VSYS voltage regulation values */
static const struct linear_range vsys_voltage_regulation_ranges[] = {
        LINEAR_RANGE(2560000, 0, 0x28, 0),
        LINEAR_RANGE(2560000, 0x28, 0x12C, 64000),
        LINEAR_RANGE(19200000, 0x12C, 0x1FF, 0),
};

/* Possible settings for switching from trickle to pre-charging limits */
static const struct linear_range trickle_to_pre_threshold_ranges[] = {
        LINEAR_RANGE(2048000, 0, 0x20, 0),
        LINEAR_RANGE(2048000, 0x20, 0x12C, 64000),
        LINEAR_RANGE(19200000, 0x12C, 0x1FF, 0),
};

/* Possible current values for fast-charging constant current phase */
static const struct linear_range fast_charge_current_ranges[] = {
        LINEAR_RANGE(0, 0, 0xFF, 64000),
};

struct battery_init {
        const char *name;
        int *info_data;
        const struct linear_range *range;
        int ranges;
        u16 *data;
};

struct dt_init {
        char *prop;
        const struct linear_range *range;
        int ranges;
        u16 *data;
};

static int bd9995x_fw_probe(struct bd9995x_device *bd)
{
        int ret;
        struct power_supply_battery_info *info;
        u32 property;
        int i;
        int regval;
        bool found;
        struct bd9995x_init_data *init = &bd->init_data;
        struct battery_init battery_inits[] = {
                {
                        .name = "trickle-charging current",
                        .range = &charging_current_ranges[0],
                        .ranges = 2,
                        .data = &init->itrich_set,
                }, {
                        .name = "pre-charging current",
                        .range = &charging_current_ranges[0],
                        .ranges = 2,
                        .data = &init->iprech_set,
                }, {
                        .name = "pre-to-trickle charge voltage threshold",
                        .range = &trickle_to_pre_threshold_ranges[0],
                        .ranges = 2,
                        .data = &init->vprechg_th_set,
                }, {
                        .name = "charging termination current",
                        .range = &charging_current_ranges[0],
                        .ranges = 2,
                        .data = &init->iterm_set,
                }, {
                        .name = "charging re-start voltage",
                        .range = &charge_voltage_regulation_ranges[0],
                        .ranges = 2,
                        .data = &init->vrechg_set,
                }, {
                        .name = "battery overvoltage limit",
                        .range = &charge_voltage_regulation_ranges[0],
                        .ranges = 2,
                        .data = &init->vbatovp_set,
                }, {
                        .name = "fast-charging max current",
                        .range = &fast_charge_current_ranges[0],
                        .ranges = 1,
                        .data = &init->ichg_set,
                }, {
                        .name = "fast-charging voltage",
                        .range = &charge_voltage_regulation_ranges[0],
                        .ranges = 2,
                        .data = &init->vfastchg_reg_set1,
                },
        };
        struct dt_init props[] = {
                {
                        .prop = "rohm,vsys-regulation-microvolt",
                        .range = &vsys_voltage_regulation_ranges[0],
                        .ranges = 2,
                        .data = &init->vsysreg_set,
                }, {
                        .prop = "rohm,vbus-input-current-limit-microamp",
                        .range = &input_current_limit_ranges[0],
                        .ranges = 1,
                        .data = &init->ibus_lim_set,
                }, {
                        .prop = "rohm,vcc-input-current-limit-microamp",
                        .range = &input_current_limit_ranges[0],
                        .ranges = 1,
                        .data = &init->icc_lim_set,
                },
        };

        /*
         * The power_supply_get_battery_info() does not support getting values
         * from ACPI. Let's fix it if ACPI is required here.
         */
        ret = power_supply_get_battery_info(bd->charger, &info);
        if (ret < 0)
                return ret;

        /* Put pointers to the generic battery info */
        battery_inits[0].info_data = &info->tricklecharge_current_ua;
        battery_inits[1].info_data = &info->precharge_current_ua;
        battery_inits[2].info_data = &info->precharge_voltage_max_uv;
        battery_inits[3].info_data = &info->charge_term_current_ua;
        battery_inits[4].info_data = &info->charge_restart_voltage_uv;
        battery_inits[5].info_data = &info->overvoltage_limit_uv;
        battery_inits[6].info_data = &info->constant_charge_current_max_ua;
        battery_inits[7].info_data = &info->constant_charge_voltage_max_uv;

        for (i = 0; i < ARRAY_SIZE(battery_inits); i++) {
                int val = *battery_inits[i].info_data;
                const struct linear_range *range = battery_inits[i].range;
                int ranges = battery_inits[i].ranges;

                if (val == -EINVAL)
                        continue;

                ret = linear_range_get_selector_low_array(range, ranges, val,
                                                          &regval, &found);
                if (ret) {
                        dev_err(bd->dev, "Unsupported value for %s\n",
                                battery_inits[i].name);

                        power_supply_put_battery_info(bd->charger, info);
                        return -EINVAL;
                }
                if (!found) {
                        dev_warn(bd->dev,
                                 "Unsupported value for %s - using smaller\n",
                                 battery_inits[i].name);
                }
                *(battery_inits[i].data) = regval;
        }

        power_supply_put_battery_info(bd->charger, info);

        for (i = 0; i < ARRAY_SIZE(props); i++) {
                ret = device_property_read_u32(bd->dev, props[i].prop,
                                               &property);
                if (ret < 0) {
                        dev_err(bd->dev, "failed to read %s", props[i].prop);

                        return ret;
                }

                ret = linear_range_get_selector_low_array(props[i].range,
                                                          props[i].ranges,
                                                          property, &regval,
                                                          &found);
                if (ret) {
                        dev_err(bd->dev, "Unsupported value for '%s'\n",
                                props[i].prop);

                        return -EINVAL;
                }

                if (!found) {
                        dev_warn(bd->dev,
                                 "Unsupported value for '%s' - using smaller\n",
                                 props[i].prop);
                }

                *(props[i].data) = regval;
        }

        return 0;
}

static void bd9995x_chip_reset(void *bd)
{
        __bd9995x_chip_reset(bd);
}

static int bd9995x_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct bd9995x_device *bd;
        struct power_supply_config psy_cfg = {};
        int ret;
        int i;

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

        bd->client = client;
        bd->dev = dev;
        psy_cfg.drv_data = bd;
        psy_cfg.fwnode = dev_fwnode(dev);

        mutex_init(&bd->lock);

        bd->rmap = devm_regmap_init_i2c(client, &bd9995x_regmap_config);
        if (IS_ERR(bd->rmap)) {
                dev_err(dev, "Failed to setup register access via i2c\n");
                return PTR_ERR(bd->rmap);
        }

        for (i = 0; i < ARRAY_SIZE(bd9995x_reg_fields); i++) {
                const struct reg_field *reg_fields = bd9995x_reg_fields;

                bd->rmap_fields[i] = devm_regmap_field_alloc(dev, bd->rmap,
                                                             reg_fields[i]);
                if (IS_ERR(bd->rmap_fields[i])) {
                        dev_err(dev, "cannot allocate regmap field\n");
                        return PTR_ERR(bd->rmap_fields[i]);
                }
        }

        i2c_set_clientdata(client, bd);

        ret = regmap_field_read(bd->rmap_fields[F_CHIP_ID], &bd->chip_id);
        if (ret) {
                dev_err(dev, "Cannot read chip ID.\n");
                return ret;
        }

        if (bd->chip_id != BD99954_ID) {
                dev_err(dev, "Chip with ID=0x%x, not supported!\n",
                        bd->chip_id);
                return -ENODEV;
        }

        ret = regmap_field_read(bd->rmap_fields[F_CHIP_REV], &bd->chip_rev);
        if (ret) {
                dev_err(dev, "Cannot read revision.\n");
                return ret;
        }

        dev_info(bd->dev, "Found BD99954 chip rev %d\n", bd->chip_rev);

        /*
         * We need to init the psy before we can call
         * power_supply_get_battery_info() for it
         */
        bd->charger = devm_power_supply_register(bd->dev,
                                                 &bd9995x_power_supply_desc,
                                                &psy_cfg);
        if (IS_ERR(bd->charger)) {
                dev_err(dev, "Failed to register power supply\n");
                return PTR_ERR(bd->charger);
        }

        ret = bd9995x_fw_probe(bd);
        if (ret < 0) {
                dev_err(dev, "Cannot read device properties.\n");
                return ret;
        }

        ret = bd9995x_hw_init(bd);
        if (ret < 0) {
                dev_err(dev, "Cannot initialize the chip.\n");
                return ret;
        }

        ret = devm_add_action_or_reset(dev, bd9995x_chip_reset, bd);
        if (ret)
                return ret;

        return devm_request_threaded_irq(dev, client->irq, NULL,
                                         bd9995x_irq_handler_thread,
                                         IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                         BD9995X_IRQ_PIN, bd);
}

static const struct of_device_id bd9995x_of_match[] = {
        { .compatible = "rohm,bd99954", },
        { }
};
MODULE_DEVICE_TABLE(of, bd9995x_of_match);

static struct i2c_driver bd9995x_driver = {
        .driver = {
                .name = "bd9995x-charger",
                .of_match_table = bd9995x_of_match,
        },
        .probe = bd9995x_probe,
};
module_i2c_driver(bd9995x_driver);

MODULE_AUTHOR("Laine Markus <markus.laine@fi.rohmeurope.com>");
MODULE_DESCRIPTION("ROHM BD99954 charger driver");
MODULE_LICENSE("GPL");