/*
 * Summit Microelectronics SMB347 Battery Charger Driver
 *
 * Copyright (C) 2011, Intel Corporation
 *
 * Authors: Bruce E. Robertson <bruce.e.robertson@intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/power_supply.h>
#include <linux/power/smb347-charger.h>
#include <linux/regmap.h>

/*
 * Configuration registers. These are mirrored to volatile RAM and can be
 * written once %CMD_A_ALLOW_WRITE is set in %CMD_A register. They will be
 * reloaded from non-volatile registers after POR.
 */
#define CFG_CHARGE_CURRENT                      0x00
#define CFG_CHARGE_CURRENT_FCC_MASK             0xe0
#define CFG_CHARGE_CURRENT_FCC_SHIFT            5
#define CFG_CHARGE_CURRENT_PCC_MASK             0x18
#define CFG_CHARGE_CURRENT_PCC_SHIFT            3
#define CFG_CHARGE_CURRENT_TC_MASK              0x07
#define CFG_CURRENT_LIMIT                       0x01
#define CFG_CURRENT_LIMIT_DC_MASK               0xf0
#define CFG_CURRENT_LIMIT_DC_SHIFT              4
#define CFG_CURRENT_LIMIT_USB_MASK              0x0f
#define CFG_FLOAT_VOLTAGE                       0x03
#define CFG_FLOAT_VOLTAGE_FLOAT_MASK            0x3f
#define CFG_FLOAT_VOLTAGE_THRESHOLD_MASK        0xc0
#define CFG_FLOAT_VOLTAGE_THRESHOLD_SHIFT       6
#define CFG_STAT                                0x05
#define CFG_STAT_DISABLED                       BIT(5)
#define CFG_STAT_ACTIVE_HIGH                    BIT(7)
#define CFG_PIN                                 0x06
#define CFG_PIN_EN_CTRL_MASK                    0x60
#define CFG_PIN_EN_CTRL_ACTIVE_HIGH             0x40
#define CFG_PIN_EN_CTRL_ACTIVE_LOW              0x60
#define CFG_PIN_EN_APSD_IRQ                     BIT(1)
#define CFG_PIN_EN_CHARGER_ERROR                BIT(2)
#define CFG_THERM                               0x07
#define CFG_THERM_SOFT_HOT_COMPENSATION_MASK    0x03
#define CFG_THERM_SOFT_HOT_COMPENSATION_SHIFT   0
#define CFG_THERM_SOFT_COLD_COMPENSATION_MASK   0x0c
#define CFG_THERM_SOFT_COLD_COMPENSATION_SHIFT  2
#define CFG_THERM_MONITOR_DISABLED              BIT(4)
#define CFG_SYSOK                               0x08
#define CFG_SYSOK_SUSPEND_HARD_LIMIT_DISABLED   BIT(2)
#define CFG_OTHER                               0x09
#define CFG_OTHER_RID_MASK                      0xc0
#define CFG_OTHER_RID_ENABLED_AUTO_OTG          0xc0
#define CFG_OTG                                 0x0a
#define CFG_OTG_TEMP_THRESHOLD_MASK             0x30
#define CFG_OTG_TEMP_THRESHOLD_SHIFT            4
#define CFG_OTG_CC_COMPENSATION_MASK            0xc0
#define CFG_OTG_CC_COMPENSATION_SHIFT           6
#define CFG_TEMP_LIMIT                          0x0b
#define CFG_TEMP_LIMIT_SOFT_HOT_MASK            0x03
#define CFG_TEMP_LIMIT_SOFT_HOT_SHIFT           0
#define CFG_TEMP_LIMIT_SOFT_COLD_MASK           0x0c
#define CFG_TEMP_LIMIT_SOFT_COLD_SHIFT          2
#define CFG_TEMP_LIMIT_HARD_HOT_MASK            0x30
#define CFG_TEMP_LIMIT_HARD_HOT_SHIFT           4
#define CFG_TEMP_LIMIT_HARD_COLD_MASK           0xc0
#define CFG_TEMP_LIMIT_HARD_COLD_SHIFT          6
#define CFG_FAULT_IRQ                           0x0c
#define CFG_FAULT_IRQ_DCIN_UV                   BIT(2)
#define CFG_STATUS_IRQ                          0x0d
#define CFG_STATUS_IRQ_TERMINATION_OR_TAPER     BIT(4)
#define CFG_STATUS_IRQ_CHARGE_TIMEOUT           BIT(7)
#define CFG_ADDRESS                             0x0e

/* Command registers */
#define CMD_A                                   0x30
#define CMD_A_CHG_ENABLED                       BIT(1)
#define CMD_A_SUSPEND_ENABLED                   BIT(2)
#define CMD_A_ALLOW_WRITE                       BIT(7)
#define CMD_B                                   0x31
#define CMD_C                                   0x33

/* Interrupt Status registers */
#define IRQSTAT_A                               0x35
#define IRQSTAT_C                               0x37
#define IRQSTAT_C_TERMINATION_STAT              BIT(0)
#define IRQSTAT_C_TERMINATION_IRQ               BIT(1)
#define IRQSTAT_C_TAPER_IRQ                     BIT(3)
#define IRQSTAT_D                               0x38
#define IRQSTAT_D_CHARGE_TIMEOUT_STAT           BIT(2)
#define IRQSTAT_D_CHARGE_TIMEOUT_IRQ            BIT(3)
#define IRQSTAT_E                               0x39
#define IRQSTAT_E_USBIN_UV_STAT                 BIT(0)
#define IRQSTAT_E_USBIN_UV_IRQ                  BIT(1)
#define IRQSTAT_E_DCIN_UV_STAT                  BIT(4)
#define IRQSTAT_E_DCIN_UV_IRQ                   BIT(5)
#define IRQSTAT_F                               0x3a

/* Status registers */
#define STAT_A                                  0x3b
#define STAT_A_FLOAT_VOLTAGE_MASK               0x3f
#define STAT_B                                  0x3c
#define STAT_C                                  0x3d
#define STAT_C_CHG_ENABLED                      BIT(0)
#define STAT_C_HOLDOFF_STAT                     BIT(3)
#define STAT_C_CHG_MASK                         0x06
#define STAT_C_CHG_SHIFT                        1
#define STAT_C_CHG_TERM                         BIT(5)
#define STAT_C_CHARGER_ERROR                    BIT(6)
#define STAT_E                                  0x3f

#define SMB347_MAX_REGISTER                     0x3f

/**
 * struct smb347_charger - smb347 charger instance
 * @lock: protects concurrent access to online variables
 * @dev: pointer to device
 * @regmap: pointer to driver regmap
 * @mains: power_supply instance for AC/DC power
 * @usb: power_supply instance for USB power
 * @battery: power_supply instance for battery
 * @mains_online: is AC/DC input connected
 * @usb_online: is USB input connected
 * @charging_enabled: is charging enabled
 * @pdata: pointer to platform data
 */
struct smb347_charger {
        struct mutex            lock;
        struct device           *dev;
        struct regmap           *regmap;
        struct power_supply     mains;
        struct power_supply     usb;
        struct power_supply     battery;
        bool                    mains_online;
        bool                    usb_online;
        bool                    charging_enabled;
        const struct smb347_charger_platform_data *pdata;
};

/* Fast charge current in uA */
static const unsigned int fcc_tbl[] = {
        700000,
        900000,
        1200000,
        1500000,
        1800000,
        2000000,
        2200000,
        2500000,
};

/* Pre-charge current in uA */
static const unsigned int pcc_tbl[] = {
        100000,
        150000,
        200000,
        250000,
};

/* Termination current in uA */
static const unsigned int tc_tbl[] = {
        37500,
        50000,
        100000,
        150000,
        200000,
        250000,
        500000,
        600000,
};

/* Input current limit in uA */
static const unsigned int icl_tbl[] = {
        300000,
        500000,
        700000,
        900000,
        1200000,
        1500000,
        1800000,
        2000000,
        2200000,
        2500000,
};

/* Charge current compensation in uA */
static const unsigned int ccc_tbl[] = {
        250000,
        700000,
        900000,
        1200000,
};

/* Convert register value to current using lookup table */
static int hw_to_current(const unsigned int *tbl, size_t size, unsigned int val)
{
        if (val >= size)
                return -EINVAL;
        return tbl[val];
}

/* Convert current to register value using lookup table */
static int current_to_hw(const unsigned int *tbl, size_t size, unsigned int val)
{
        size_t i;

        for (i = 0; i < size; i++)
                if (val < tbl[i])
                        break;
        return i > 0 ? i - 1 : -EINVAL;
}

/**
 * smb347_update_ps_status - refreshes the power source status
 * @smb: pointer to smb347 charger instance
 *
 * Function checks whether any power source is connected to the charger and
 * updates internal state accordingly. If there is a change to previous state
 * function returns %1, otherwise %0 and negative errno in case of errror.
 */
static int smb347_update_ps_status(struct smb347_charger *smb)
{
        bool usb = false;
        bool dc = false;
        unsigned int val;
        int ret;

        ret = regmap_read(smb->regmap, IRQSTAT_E, &val);
        if (ret < 0)
                return ret;

        /*
         * Dc and usb are set depending on whether they are enabled in
         * platform data _and_ whether corresponding undervoltage is set.
         */
        if (smb->pdata->use_mains)
                dc = !(val & IRQSTAT_E_DCIN_UV_STAT);
        if (smb->pdata->use_usb)
                usb = !(val & IRQSTAT_E_USBIN_UV_STAT);

        mutex_lock(&smb->lock);
        ret = smb->mains_online != dc || smb->usb_online != usb;
        smb->mains_online = dc;
        smb->usb_online = usb;
        mutex_unlock(&smb->lock);

        return ret;
}

/*
 * smb347_is_ps_online - returns whether input power source is connected
 * @smb: pointer to smb347 charger instance
 *
 * Returns %true if input power source is connected. Note that this is
 * dependent on what platform has configured for usable power sources. For
 * example if USB is disabled, this will return %false even if the USB cable
 * is connected.
 */
static bool smb347_is_ps_online(struct smb347_charger *smb)
{
        bool ret;

        mutex_lock(&smb->lock);
        ret = smb->usb_online || smb->mains_online;
        mutex_unlock(&smb->lock);

        return ret;
}

/**
 * smb347_charging_status - returns status of charging
 * @smb: pointer to smb347 charger instance
 *
 * Function returns charging status. %0 means no charging is in progress,
 * %1 means pre-charging, %2 fast-charging and %3 taper-charging.
 */
static int smb347_charging_status(struct smb347_charger *smb)
{
        unsigned int val;
        int ret;

        if (!smb347_is_ps_online(smb))
                return 0;

        ret = regmap_read(smb->regmap, STAT_C, &val);
        if (ret < 0)
                return 0;

        return (val & STAT_C_CHG_MASK) >> STAT_C_CHG_SHIFT;
}

static int smb347_charging_set(struct smb347_charger *smb, bool enable)
{
        int ret = 0;

        if (smb->pdata->enable_control != SMB347_CHG_ENABLE_SW) {
                dev_dbg(smb->dev, "charging enable/disable in SW disabled\n");
                return 0;
        }

        mutex_lock(&smb->lock);
        if (smb->charging_enabled != enable) {
                ret = regmap_update_bits(smb->regmap, CMD_A, CMD_A_CHG_ENABLED,
                                         enable ? CMD_A_CHG_ENABLED : 0);
                if (!ret)
                        smb->charging_enabled = enable;
        }
        mutex_unlock(&smb->lock);
        return ret;
}

static inline int smb347_charging_enable(struct smb347_charger *smb)
{
        return smb347_charging_set(smb, true);
}

static inline int smb347_charging_disable(struct smb347_charger *smb)
{
        return smb347_charging_set(smb, false);
}

static int smb347_start_stop_charging(struct smb347_charger *smb)
{
        int ret;

        /*
         * Depending on whether valid power source is connected or not, we
         * disable or enable the charging. We do it manually because it
         * depends on how the platform has configured the valid inputs.
         */
        if (smb347_is_ps_online(smb)) {
                ret = smb347_charging_enable(smb);
                if (ret < 0)
                        dev_err(smb->dev, "failed to enable charging\n");
        } else {
                ret = smb347_charging_disable(smb);
                if (ret < 0)
                        dev_err(smb->dev, "failed to disable charging\n");
        }

        return ret;
}

static int smb347_set_charge_current(struct smb347_charger *smb)
{
        int ret;

        if (smb->pdata->max_charge_current) {
                ret = current_to_hw(fcc_tbl, ARRAY_SIZE(fcc_tbl),
                                    smb->pdata->max_charge_current);
                if (ret < 0)
                        return ret;

                ret = regmap_update_bits(smb->regmap, CFG_CHARGE_CURRENT,
                                         CFG_CHARGE_CURRENT_FCC_MASK,
                                         ret << CFG_CHARGE_CURRENT_FCC_SHIFT);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->pre_charge_current) {
                ret = current_to_hw(pcc_tbl, ARRAY_SIZE(pcc_tbl),
                                    smb->pdata->pre_charge_current);
                if (ret < 0)
                        return ret;

                ret = regmap_update_bits(smb->regmap, CFG_CHARGE_CURRENT,
                                         CFG_CHARGE_CURRENT_PCC_MASK,
                                         ret << CFG_CHARGE_CURRENT_PCC_SHIFT);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->termination_current) {
                ret = current_to_hw(tc_tbl, ARRAY_SIZE(tc_tbl),
                                    smb->pdata->termination_current);
                if (ret < 0)
                        return ret;

                ret = regmap_update_bits(smb->regmap, CFG_CHARGE_CURRENT,
                                         CFG_CHARGE_CURRENT_TC_MASK, ret);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int smb347_set_current_limits(struct smb347_charger *smb)
{
        int ret;

        if (smb->pdata->mains_current_limit) {
                ret = current_to_hw(icl_tbl, ARRAY_SIZE(icl_tbl),
                                    smb->pdata->mains_current_limit);
                if (ret < 0)
                        return ret;

                ret = regmap_update_bits(smb->regmap, CFG_CURRENT_LIMIT,
                                         CFG_CURRENT_LIMIT_DC_MASK,
                                         ret << CFG_CURRENT_LIMIT_DC_SHIFT);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->usb_hc_current_limit) {
                ret = current_to_hw(icl_tbl, ARRAY_SIZE(icl_tbl),
                                    smb->pdata->usb_hc_current_limit);
                if (ret < 0)
                        return ret;

                ret = regmap_update_bits(smb->regmap, CFG_CURRENT_LIMIT,
                                         CFG_CURRENT_LIMIT_USB_MASK, ret);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int smb347_set_voltage_limits(struct smb347_charger *smb)
{
        int ret;

        if (smb->pdata->pre_to_fast_voltage) {
                ret = smb->pdata->pre_to_fast_voltage;

                /* uV */
                ret = clamp_val(ret, 2400000, 3000000) - 2400000;
                ret /= 200000;

                ret = regmap_update_bits(smb->regmap, CFG_FLOAT_VOLTAGE,
                                CFG_FLOAT_VOLTAGE_THRESHOLD_MASK,
                                ret << CFG_FLOAT_VOLTAGE_THRESHOLD_SHIFT);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->max_charge_voltage) {
                ret = smb->pdata->max_charge_voltage;

                /* uV */
                ret = clamp_val(ret, 3500000, 4500000) - 3500000;
                ret /= 20000;

                ret = regmap_update_bits(smb->regmap, CFG_FLOAT_VOLTAGE,
                                         CFG_FLOAT_VOLTAGE_FLOAT_MASK, ret);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int smb347_set_temp_limits(struct smb347_charger *smb)
{
        bool enable_therm_monitor = false;
        int ret = 0;
        int val;

        if (smb->pdata->chip_temp_threshold) {
                val = smb->pdata->chip_temp_threshold;

                /* degree C */
                val = clamp_val(val, 100, 130) - 100;
                val /= 10;

                ret = regmap_update_bits(smb->regmap, CFG_OTG,
                                         CFG_OTG_TEMP_THRESHOLD_MASK,
                                         val << CFG_OTG_TEMP_THRESHOLD_SHIFT);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->soft_cold_temp_limit != SMB347_TEMP_USE_DEFAULT) {
                val = smb->pdata->soft_cold_temp_limit;

                val = clamp_val(val, 0, 15);
                val /= 5;
                /* this goes from higher to lower so invert the value */
                val = ~val & 0x3;

                ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
                                         CFG_TEMP_LIMIT_SOFT_COLD_MASK,
                                         val << CFG_TEMP_LIMIT_SOFT_COLD_SHIFT);
                if (ret < 0)
                        return ret;

                enable_therm_monitor = true;
        }

        if (smb->pdata->soft_hot_temp_limit != SMB347_TEMP_USE_DEFAULT) {
                val = smb->pdata->soft_hot_temp_limit;

                val = clamp_val(val, 40, 55) - 40;
                val /= 5;

                ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
                                         CFG_TEMP_LIMIT_SOFT_HOT_MASK,
                                         val << CFG_TEMP_LIMIT_SOFT_HOT_SHIFT);
                if (ret < 0)
                        return ret;

                enable_therm_monitor = true;
        }

        if (smb->pdata->hard_cold_temp_limit != SMB347_TEMP_USE_DEFAULT) {
                val = smb->pdata->hard_cold_temp_limit;

                val = clamp_val(val, -5, 10) + 5;
                val /= 5;
                /* this goes from higher to lower so invert the value */
                val = ~val & 0x3;

                ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
                                         CFG_TEMP_LIMIT_HARD_COLD_MASK,
                                         val << CFG_TEMP_LIMIT_HARD_COLD_SHIFT);
                if (ret < 0)
                        return ret;

                enable_therm_monitor = true;
        }

        if (smb->pdata->hard_hot_temp_limit != SMB347_TEMP_USE_DEFAULT) {
                val = smb->pdata->hard_hot_temp_limit;

                val = clamp_val(val, 50, 65) - 50;
                val /= 5;

                ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
                                         CFG_TEMP_LIMIT_HARD_HOT_MASK,
                                         val << CFG_TEMP_LIMIT_HARD_HOT_SHIFT);
                if (ret < 0)
                        return ret;

                enable_therm_monitor = true;
        }

        /*
         * If any of the temperature limits are set, we also enable the
         * thermistor monitoring.
         *
         * When soft limits are hit, the device will start to compensate
         * current and/or voltage depending on the configuration.
         *
         * When hard limit is hit, the device will suspend charging
         * depending on the configuration.
         */
        if (enable_therm_monitor) {
                ret = regmap_update_bits(smb->regmap, CFG_THERM,
                                         CFG_THERM_MONITOR_DISABLED, 0);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->suspend_on_hard_temp_limit) {
                ret = regmap_update_bits(smb->regmap, CFG_SYSOK,
                                 CFG_SYSOK_SUSPEND_HARD_LIMIT_DISABLED, 0);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->soft_temp_limit_compensation !=
            SMB347_SOFT_TEMP_COMPENSATE_DEFAULT) {
                val = smb->pdata->soft_temp_limit_compensation & 0x3;

                ret = regmap_update_bits(smb->regmap, CFG_THERM,
                                 CFG_THERM_SOFT_HOT_COMPENSATION_MASK,
                                 val << CFG_THERM_SOFT_HOT_COMPENSATION_SHIFT);
                if (ret < 0)
                        return ret;

                ret = regmap_update_bits(smb->regmap, CFG_THERM,
                                 CFG_THERM_SOFT_COLD_COMPENSATION_MASK,
                                 val << CFG_THERM_SOFT_COLD_COMPENSATION_SHIFT);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->charge_current_compensation) {
                val = current_to_hw(ccc_tbl, ARRAY_SIZE(ccc_tbl),
                                    smb->pdata->charge_current_compensation);
                if (val < 0)
                        return val;

                ret = regmap_update_bits(smb->regmap, CFG_OTG,
                                CFG_OTG_CC_COMPENSATION_MASK,
                                (val & 0x3) << CFG_OTG_CC_COMPENSATION_SHIFT);
                if (ret < 0)
                        return ret;
        }

        return ret;
}

/*
 * smb347_set_writable - enables/disables writing to non-volatile registers
 * @smb: pointer to smb347 charger instance
 *
 * You can enable/disable writing to the non-volatile configuration
 * registers by calling this function.
 *
 * Returns %0 on success and negative errno in case of failure.
 */
static int smb347_set_writable(struct smb347_charger *smb, bool writable)
{
        return regmap_update_bits(smb->regmap, CMD_A, CMD_A_ALLOW_WRITE,
                                  writable ? CMD_A_ALLOW_WRITE : 0);
}

static int smb347_hw_init(struct smb347_charger *smb)
{
        unsigned int val;
        int ret;

        ret = smb347_set_writable(smb, true);
        if (ret < 0)
                return ret;

        /*
         * Program the platform specific configuration values to the device
         * first.
         */
        ret = smb347_set_charge_current(smb);
        if (ret < 0)
                goto fail;

        ret = smb347_set_current_limits(smb);
        if (ret < 0)
                goto fail;

        ret = smb347_set_voltage_limits(smb);
        if (ret < 0)
                goto fail;

        ret = smb347_set_temp_limits(smb);
        if (ret < 0)
                goto fail;

        /* If USB charging is disabled we put the USB in suspend mode */
        if (!smb->pdata->use_usb) {
                ret = regmap_update_bits(smb->regmap, CMD_A,
                                         CMD_A_SUSPEND_ENABLED,
                                         CMD_A_SUSPEND_ENABLED);
                if (ret < 0)
                        goto fail;
        }

        /*
         * If configured by platform data, we enable hardware Auto-OTG
         * support for driving VBUS. Otherwise we disable it.
         */
        ret = regmap_update_bits(smb->regmap, CFG_OTHER, CFG_OTHER_RID_MASK,
                smb->pdata->use_usb_otg ? CFG_OTHER_RID_ENABLED_AUTO_OTG : 0);
        if (ret < 0)
                goto fail;

        /*
         * Make the charging functionality controllable by a write to the
         * command register unless pin control is specified in the platform
         * data.
         */
        switch (smb->pdata->enable_control) {
        case SMB347_CHG_ENABLE_PIN_ACTIVE_LOW:
                val = CFG_PIN_EN_CTRL_ACTIVE_LOW;
                break;
        case SMB347_CHG_ENABLE_PIN_ACTIVE_HIGH:
                val = CFG_PIN_EN_CTRL_ACTIVE_HIGH;
                break;
        default:
                val = 0;
                break;
        }

        ret = regmap_update_bits(smb->regmap, CFG_PIN, CFG_PIN_EN_CTRL_MASK,
                                 val);
        if (ret < 0)
                goto fail;

        /* Disable Automatic Power Source Detection (APSD) interrupt. */
        ret = regmap_update_bits(smb->regmap, CFG_PIN, CFG_PIN_EN_APSD_IRQ, 0);
        if (ret < 0)
                goto fail;

        ret = smb347_update_ps_status(smb);
        if (ret < 0)
                goto fail;

        ret = smb347_start_stop_charging(smb);

fail:
        smb347_set_writable(smb, false);
        return ret;
}

static irqreturn_t smb347_interrupt(int irq, void *data)
{
        struct smb347_charger *smb = data;
        unsigned int stat_c, irqstat_c, irqstat_d, irqstat_e;
        bool handled = false;
        int ret;

        ret = regmap_read(smb->regmap, STAT_C, &stat_c);
        if (ret < 0) {
                dev_warn(smb->dev, "reading STAT_C failed\n");
                return IRQ_NONE;
        }

        ret = regmap_read(smb->regmap, IRQSTAT_C, &irqstat_c);
        if (ret < 0) {
                dev_warn(smb->dev, "reading IRQSTAT_C failed\n");
                return IRQ_NONE;
        }

        ret = regmap_read(smb->regmap, IRQSTAT_D, &irqstat_d);
        if (ret < 0) {
                dev_warn(smb->dev, "reading IRQSTAT_D failed\n");
                return IRQ_NONE;
        }

        ret = regmap_read(smb->regmap, IRQSTAT_E, &irqstat_e);
        if (ret < 0) {
                dev_warn(smb->dev, "reading IRQSTAT_E failed\n");
                return IRQ_NONE;
        }

        /*
         * If we get charger error we report the error back to user.
         * If the error is recovered charging will resume again.
         */
        if (stat_c & STAT_C_CHARGER_ERROR) {
                dev_err(smb->dev, "charging stopped due to charger error\n");
                power_supply_changed(&smb->battery);
                handled = true;
        }

        /*
         * If we reached the termination current the battery is charged and
         * we can update the status now. Charging is automatically
         * disabled by the hardware.
         */
        if (irqstat_c & (IRQSTAT_C_TERMINATION_IRQ | IRQSTAT_C_TAPER_IRQ)) {
                if (irqstat_c & IRQSTAT_C_TERMINATION_STAT)
                        power_supply_changed(&smb->battery);
                dev_dbg(smb->dev, "going to HW maintenance mode\n");
                handled = true;
        }

        /*
         * If we got a charger timeout INT that means the charge
         * full is not detected with in charge timeout value.
         */
        if (irqstat_d & IRQSTAT_D_CHARGE_TIMEOUT_IRQ) {
                dev_dbg(smb->dev, "total Charge Timeout INT received\n");

                if (irqstat_d & IRQSTAT_D_CHARGE_TIMEOUT_STAT)
                        dev_warn(smb->dev, "charging stopped due to timeout\n");
                power_supply_changed(&smb->battery);
                handled = true;
        }

        /*
         * If we got an under voltage interrupt it means that AC/USB input
         * was connected or disconnected.
         */
        if (irqstat_e & (IRQSTAT_E_USBIN_UV_IRQ | IRQSTAT_E_DCIN_UV_IRQ)) {
                if (smb347_update_ps_status(smb) > 0) {
                        smb347_start_stop_charging(smb);
                        if (smb->pdata->use_mains)
                                power_supply_changed(&smb->mains);
                        if (smb->pdata->use_usb)
                                power_supply_changed(&smb->usb);
                }
                handled = true;
        }

        return handled ? IRQ_HANDLED : IRQ_NONE;
}

static int smb347_irq_set(struct smb347_charger *smb, bool enable)
{
        int ret;

        ret = smb347_set_writable(smb, true);
        if (ret < 0)
                return ret;

        /*
         * Enable/disable interrupts for:
         *      - under voltage
         *      - termination current reached
         *      - charger timeout
         *      - charger error
         */
        ret = regmap_update_bits(smb->regmap, CFG_FAULT_IRQ, 0xff,
                                 enable ? CFG_FAULT_IRQ_DCIN_UV : 0);
        if (ret < 0)
                goto fail;

        ret = regmap_update_bits(smb->regmap, CFG_STATUS_IRQ, 0xff,
                        enable ? (CFG_STATUS_IRQ_TERMINATION_OR_TAPER |
                                        CFG_STATUS_IRQ_CHARGE_TIMEOUT) : 0);
        if (ret < 0)
                goto fail;

        ret = regmap_update_bits(smb->regmap, CFG_PIN, CFG_PIN_EN_CHARGER_ERROR,
                                 enable ? CFG_PIN_EN_CHARGER_ERROR : 0);
fail:
        smb347_set_writable(smb, false);
        return ret;
}

static inline int smb347_irq_enable(struct smb347_charger *smb)
{
        return smb347_irq_set(smb, true);
}

static inline int smb347_irq_disable(struct smb347_charger *smb)
{
        return smb347_irq_set(smb, false);
}

static int smb347_irq_init(struct smb347_charger *smb,
                           struct i2c_client *client)
{
        const struct smb347_charger_platform_data *pdata = smb->pdata;
        int ret, irq = gpio_to_irq(pdata->irq_gpio);

        ret = gpio_request_one(pdata->irq_gpio, GPIOF_IN, client->name);
        if (ret < 0)
                goto fail;

        ret = request_threaded_irq(irq, NULL, smb347_interrupt,
                                   IRQF_TRIGGER_FALLING, client->name, smb);
        if (ret < 0)
                goto fail_gpio;

        ret = smb347_set_writable(smb, true);
        if (ret < 0)
                goto fail_irq;

        /*
         * Configure the STAT output to be suitable for interrupts: disable
         * all other output (except interrupts) and make it active low.
         */
        ret = regmap_update_bits(smb->regmap, CFG_STAT,
                                 CFG_STAT_ACTIVE_HIGH | CFG_STAT_DISABLED,
                                 CFG_STAT_DISABLED);
        if (ret < 0)
                goto fail_readonly;

        smb347_set_writable(smb, false);
        client->irq = irq;
        return 0;

fail_readonly:
        smb347_set_writable(smb, false);
fail_irq:
        free_irq(irq, smb);
fail_gpio:
        gpio_free(pdata->irq_gpio);
fail:
        client->irq = 0;
        return ret;
}

/*
 * Returns the constant charge current programmed
 * into the charger in uA.
 */
static int get_const_charge_current(struct smb347_charger *smb)
{
        int ret, intval;
        unsigned int v;

        if (!smb347_is_ps_online(smb))
                return -ENODATA;

        ret = regmap_read(smb->regmap, STAT_B, &v);
        if (ret < 0)
                return ret;

        /*
         * The current value is composition of FCC and PCC values
         * and we can detect which table to use from bit 5.
         */
        if (v & 0x20) {
                intval = hw_to_current(fcc_tbl, ARRAY_SIZE(fcc_tbl), v & 7);
        } else {
                v >>= 3;
                intval = hw_to_current(pcc_tbl, ARRAY_SIZE(pcc_tbl), v & 7);
        }

        return intval;
}

/*
 * Returns the constant charge voltage programmed
 * into the charger in uV.
 */
static int get_const_charge_voltage(struct smb347_charger *smb)
{
        int ret, intval;
        unsigned int v;

        if (!smb347_is_ps_online(smb))
                return -ENODATA;

        ret = regmap_read(smb->regmap, STAT_A, &v);
        if (ret < 0)
                return ret;

        v &= STAT_A_FLOAT_VOLTAGE_MASK;
        if (v > 0x3d)
                v = 0x3d;

        intval = 3500000 + v * 20000;

        return intval;
}

static int smb347_mains_get_property(struct power_supply *psy,
                                     enum power_supply_property prop,
                                     union power_supply_propval *val)
{
        struct smb347_charger *smb =
                container_of(psy, struct smb347_charger, mains);
        int ret;

        switch (prop) {
        case POWER_SUPPLY_PROP_ONLINE:
                val->intval = smb->mains_online;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                ret = get_const_charge_voltage(smb);
                if (ret < 0)
                        return ret;
                else
                        val->intval = ret;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
                ret = get_const_charge_current(smb);
                if (ret < 0)
                        return ret;
                else
                        val->intval = ret;
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

static enum power_supply_property smb347_mains_properties[] = {
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
};

static int smb347_usb_get_property(struct power_supply *psy,
                                   enum power_supply_property prop,
                                   union power_supply_propval *val)
{
        struct smb347_charger *smb =
                container_of(psy, struct smb347_charger, usb);
        int ret;

        switch (prop) {
        case POWER_SUPPLY_PROP_ONLINE:
                val->intval = smb->usb_online;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                ret = get_const_charge_voltage(smb);
                if (ret < 0)
                        return ret;
                else
                        val->intval = ret;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
                ret = get_const_charge_current(smb);
                if (ret < 0)
                        return ret;
                else

                        val->intval = ret;
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

static enum power_supply_property smb347_usb_properties[] = {
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
};

static int smb347_get_charging_status(struct smb347_charger *smb)
{
        int ret, status;
        unsigned int val;

        if (!smb347_is_ps_online(smb))
                return POWER_SUPPLY_STATUS_DISCHARGING;

        ret = regmap_read(smb->regmap, STAT_C, &val);
        if (ret < 0)
                return ret;

        if ((val & STAT_C_CHARGER_ERROR) ||
                        (val & STAT_C_HOLDOFF_STAT)) {
                /*
                 * set to NOT CHARGING upon charger error
                 * or charging has stopped.
                 */
                status = POWER_SUPPLY_STATUS_NOT_CHARGING;
        } else {
                if ((val & STAT_C_CHG_MASK) >> STAT_C_CHG_SHIFT) {
                        /*
                         * set to charging if battery is in pre-charge,
                         * fast charge or taper charging mode.
                         */
                        status = POWER_SUPPLY_STATUS_CHARGING;
                } else if (val & STAT_C_CHG_TERM) {
                        /*
                         * set the status to FULL if battery is not in pre
                         * charge, fast charge or taper charging mode AND
                         * charging is terminated at least once.
                         */
                        status = POWER_SUPPLY_STATUS_FULL;
                } else {
                        /*
                         * in this case no charger error or termination
                         * occured but charging is not in progress!!!
                         */
                        status = POWER_SUPPLY_STATUS_NOT_CHARGING;
                }
        }

        return status;
}

static int smb347_battery_get_property(struct power_supply *psy,
                                       enum power_supply_property prop,
                                       union power_supply_propval *val)
{
        struct smb347_charger *smb =
                        container_of(psy, struct smb347_charger, battery);
        const struct smb347_charger_platform_data *pdata = smb->pdata;
        int ret;

        ret = smb347_update_ps_status(smb);
        if (ret < 0)
                return ret;

        switch (prop) {
        case POWER_SUPPLY_PROP_STATUS:
                ret = smb347_get_charging_status(smb);
                if (ret < 0)
                        return ret;
                val->intval = ret;
                break;

        case POWER_SUPPLY_PROP_CHARGE_TYPE:
                if (!smb347_is_ps_online(smb))
                        return -ENODATA;

                /*
                 * We handle trickle and pre-charging the same, and taper
                 * and none the same.
                 */
                switch (smb347_charging_status(smb)) {
                case 1:
                        val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
                        break;
                case 2:
                        val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
                        break;
                default:
                        val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
                        break;
                }
                break;

        case POWER_SUPPLY_PROP_TECHNOLOGY:
                val->intval = pdata->battery_info.technology;
                break;

        case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
                val->intval = pdata->battery_info.voltage_min_design;
                break;

        case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
                val->intval = pdata->battery_info.voltage_max_design;
                break;

        case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
                val->intval = pdata->battery_info.charge_full_design;
                break;

        case POWER_SUPPLY_PROP_MODEL_NAME:
                val->strval = pdata->battery_info.name;
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

static enum power_supply_property smb347_battery_properties[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_CHARGE_TYPE,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
        POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
        POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
        POWER_SUPPLY_PROP_MODEL_NAME,
};

static bool smb347_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case IRQSTAT_A:
        case IRQSTAT_C:
        case IRQSTAT_E:
        case IRQSTAT_F:
        case STAT_A:
        case STAT_B:
        case STAT_C:
        case STAT_E:
                return true;
        }

        return false;
}

static bool smb347_readable_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case CFG_CHARGE_CURRENT:
        case CFG_CURRENT_LIMIT:
        case CFG_FLOAT_VOLTAGE:
        case CFG_STAT:
        case CFG_PIN:
        case CFG_THERM:
        case CFG_SYSOK:
        case CFG_OTHER:
        case CFG_OTG:
        case CFG_TEMP_LIMIT:
        case CFG_FAULT_IRQ:
        case CFG_STATUS_IRQ:
        case CFG_ADDRESS:
        case CMD_A:
        case CMD_B:
        case CMD_C:
                return true;
        }

        return smb347_volatile_reg(dev, reg);
}

static const struct regmap_config smb347_regmap = {
        .reg_bits       = 8,
        .val_bits       = 8,
        .max_register   = SMB347_MAX_REGISTER,
        .volatile_reg   = smb347_volatile_reg,
        .readable_reg   = smb347_readable_reg,
};

static int smb347_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        static char *battery[] = { "smb347-battery" };
        const struct smb347_charger_platform_data *pdata;
        struct device *dev = &client->dev;
        struct smb347_charger *smb;
        int ret;

        pdata = dev->platform_data;
        if (!pdata)
                return -EINVAL;

        if (!pdata->use_mains && !pdata->use_usb)
                return -EINVAL;

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

        i2c_set_clientdata(client, smb);

        mutex_init(&smb->lock);
        smb->dev = &client->dev;
        smb->pdata = pdata;

        smb->regmap = devm_regmap_init_i2c(client, &smb347_regmap);
        if (IS_ERR(smb->regmap))
                return PTR_ERR(smb->regmap);

        ret = smb347_hw_init(smb);
        if (ret < 0)
                return ret;

        if (smb->pdata->use_mains) {
                smb->mains.name = "smb347-mains";
                smb->mains.type = POWER_SUPPLY_TYPE_MAINS;
                smb->mains.get_property = smb347_mains_get_property;
                smb->mains.properties = smb347_mains_properties;
                smb->mains.num_properties = ARRAY_SIZE(smb347_mains_properties);
                smb->mains.supplied_to = battery;
                smb->mains.num_supplicants = ARRAY_SIZE(battery);
                ret = power_supply_register(dev, &smb->mains);
                if (ret < 0)
                        return ret;
        }

        if (smb->pdata->use_usb) {
                smb->usb.name = "smb347-usb";
                smb->usb.type = POWER_SUPPLY_TYPE_USB;
                smb->usb.get_property = smb347_usb_get_property;
                smb->usb.properties = smb347_usb_properties;
                smb->usb.num_properties = ARRAY_SIZE(smb347_usb_properties);
                smb->usb.supplied_to = battery;
                smb->usb.num_supplicants = ARRAY_SIZE(battery);
                ret = power_supply_register(dev, &smb->usb);
                if (ret < 0) {
                        if (smb->pdata->use_mains)
                                power_supply_unregister(&smb->mains);
                        return ret;
                }
        }

        smb->battery.name = "smb347-battery";
        smb->battery.type = POWER_SUPPLY_TYPE_BATTERY;
        smb->battery.get_property = smb347_battery_get_property;
        smb->battery.properties = smb347_battery_properties;
        smb->battery.num_properties = ARRAY_SIZE(smb347_battery_properties);


        ret = power_supply_register(dev, &smb->battery);
        if (ret < 0) {
                if (smb->pdata->use_usb)
                        power_supply_unregister(&smb->usb);
                if (smb->pdata->use_mains)
                        power_supply_unregister(&smb->mains);
                return ret;
        }

        /*
         * Interrupt pin is optional. If it is connected, we setup the
         * interrupt support here.
         */
        if (pdata->irq_gpio >= 0) {
                ret = smb347_irq_init(smb, client);
                if (ret < 0) {
                        dev_warn(dev, "failed to initialize IRQ: %d\n", ret);
                        dev_warn(dev, "disabling IRQ support\n");
                } else {
                        smb347_irq_enable(smb);
                }
        }

        return 0;
}

static int smb347_remove(struct i2c_client *client)
{
        struct smb347_charger *smb = i2c_get_clientdata(client);

        if (client->irq) {
                smb347_irq_disable(smb);
                free_irq(client->irq, smb);
                gpio_free(smb->pdata->irq_gpio);
        }

        power_supply_unregister(&smb->battery);
        if (smb->pdata->use_usb)
                power_supply_unregister(&smb->usb);
        if (smb->pdata->use_mains)
                power_supply_unregister(&smb->mains);
        return 0;
}

static const struct i2c_device_id smb347_id[] = {
        { "smb347", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, smb347_id);

static struct i2c_driver smb347_driver = {
        .driver = {
                .name = "smb347",
        },
        .probe        = smb347_probe,
        .remove       = smb347_remove,
        .id_table     = smb347_id,
};

module_i2c_driver(smb347_driver);

MODULE_AUTHOR("Bruce E. Robertson <bruce.e.robertson@intel.com>");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_DESCRIPTION("SMB347 battery charger driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("i2c:smb347");