/*
 * Battery driver for CPCAP PMIC
 *
 * Copyright (C) 2017 Tony Lindgren <tony@atomide.com>
 *
 * Some parts of the code based on earlier Motorola mapphone Linux kernel
 * drivers:
 *
 * Copyright (C) 2009-2010 Motorola, Inc.
 *
 * 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.

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#include <linux/moduleparam.h>

#include <linux/iio/consumer.h>
#include <linux/iio/types.h>
#include <linux/mfd/motorola-cpcap.h>

/*
 * Register bit defines for CPCAP_REG_BPEOL. Some of these seem to
 * map to MC13783UG.pdf "Table 5-19. Register 13, Power Control 0"
 * to enable BATTDETEN, LOBAT and EOL features. We currently use
 * LOBAT interrupts instead of EOL.
 */
#define CPCAP_REG_BPEOL_BIT_EOL9        BIT(9)  /* Set for EOL irq */
#define CPCAP_REG_BPEOL_BIT_EOL8        BIT(8)  /* Set for EOL irq */
#define CPCAP_REG_BPEOL_BIT_UNKNOWN7    BIT(7)
#define CPCAP_REG_BPEOL_BIT_UNKNOWN6    BIT(6)
#define CPCAP_REG_BPEOL_BIT_UNKNOWN5    BIT(5)
#define CPCAP_REG_BPEOL_BIT_EOL_MULTI   BIT(4)  /* Set for multiple EOL irqs */
#define CPCAP_REG_BPEOL_BIT_UNKNOWN3    BIT(3)
#define CPCAP_REG_BPEOL_BIT_UNKNOWN2    BIT(2)
#define CPCAP_REG_BPEOL_BIT_BATTDETEN   BIT(1)  /* Enable battery detect */
#define CPCAP_REG_BPEOL_BIT_EOLSEL      BIT(0)  /* BPDET = 0, EOL = 1 */

/*
 * Register bit defines for CPCAP_REG_CCC1. These seem similar to the twl6030
 * coulomb counter registers rather than the mc13892 registers. Both twl6030
 * and mc13892 set bits 2 and 1 to reset and clear registers. But mc13892
 * sets bit 0 to start the coulomb counter while twl6030 sets bit 0 to stop
 * the coulomb counter like cpcap does. So for now, we use the twl6030 style
 * naming for the registers.
 */
#define CPCAP_REG_CCC1_ACTIVE_MODE1     BIT(4)  /* Update rate */
#define CPCAP_REG_CCC1_ACTIVE_MODE0     BIT(3)  /* Update rate */
#define CPCAP_REG_CCC1_AUTOCLEAR        BIT(2)  /* Resets sample registers */
#define CPCAP_REG_CCC1_CAL_EN           BIT(1)  /* Clears after write in 1s */
#define CPCAP_REG_CCC1_PAUSE            BIT(0)  /* Stop counters, allow write */
#define CPCAP_REG_CCC1_RESET_MASK       (CPCAP_REG_CCC1_AUTOCLEAR | \
                                         CPCAP_REG_CCC1_CAL_EN)

#define CPCAP_REG_CCCC2_RATE1           BIT(5)
#define CPCAP_REG_CCCC2_RATE0           BIT(4)
#define CPCAP_REG_CCCC2_ENABLE          BIT(3)

#define CPCAP_BATTERY_CC_SAMPLE_PERIOD_MS       250

enum {
        CPCAP_BATTERY_IIO_BATTDET,
        CPCAP_BATTERY_IIO_VOLTAGE,
        CPCAP_BATTERY_IIO_CHRG_CURRENT,
        CPCAP_BATTERY_IIO_BATT_CURRENT,
        CPCAP_BATTERY_IIO_NR,
};

enum cpcap_battery_irq_action {
        CPCAP_BATTERY_IRQ_ACTION_NONE,
        CPCAP_BATTERY_IRQ_ACTION_CC_CAL_DONE,
        CPCAP_BATTERY_IRQ_ACTION_BATTERY_LOW,
        CPCAP_BATTERY_IRQ_ACTION_POWEROFF,
};

struct cpcap_interrupt_desc {
        const char *name;
        struct list_head node;
        int irq;
        enum cpcap_battery_irq_action action;
};

struct cpcap_battery_config {
        int cd_factor;
        struct power_supply_info info;
        struct power_supply_battery_info bat;
};

struct cpcap_coulomb_counter_data {
        s32 sample;             /* 24 or 32 bits */
        s32 accumulator;
        s16 offset;             /* 9 bits */
        s16 integrator;         /* 13 or 16 bits */
};

enum cpcap_battery_state {
        CPCAP_BATTERY_STATE_PREVIOUS,
        CPCAP_BATTERY_STATE_LATEST,
        CPCAP_BATTERY_STATE_EMPTY,
        CPCAP_BATTERY_STATE_FULL,
        CPCAP_BATTERY_STATE_NR,
};

struct cpcap_battery_state_data {
        int voltage;
        int current_ua;
        int counter_uah;
        int temperature;
        ktime_t time;
        struct cpcap_coulomb_counter_data cc;
};

struct cpcap_battery_ddata {
        struct device *dev;
        struct regmap *reg;
        struct list_head irq_list;
        struct iio_channel *channels[CPCAP_BATTERY_IIO_NR];
        struct power_supply *psy;
        struct cpcap_battery_config config;
        struct cpcap_battery_state_data state[CPCAP_BATTERY_STATE_NR];
        u32 cc_lsb;             /* μAms per LSB */
        atomic_t active;
        int charge_full;
        int status;
        u16 vendor;
        unsigned int is_full:1;
};

#define CPCAP_NO_BATTERY        -400

static bool ignore_temperature_probe;
module_param(ignore_temperature_probe, bool, 0660);

static struct cpcap_battery_state_data *
cpcap_battery_get_state(struct cpcap_battery_ddata *ddata,
                        enum cpcap_battery_state state)
{
        if (state >= CPCAP_BATTERY_STATE_NR)
                return NULL;

        return &ddata->state[state];
}

static struct cpcap_battery_state_data *
cpcap_battery_latest(struct cpcap_battery_ddata *ddata)
{
        return cpcap_battery_get_state(ddata, CPCAP_BATTERY_STATE_LATEST);
}

static struct cpcap_battery_state_data *
cpcap_battery_previous(struct cpcap_battery_ddata *ddata)
{
        return cpcap_battery_get_state(ddata, CPCAP_BATTERY_STATE_PREVIOUS);
}

static struct cpcap_battery_state_data *
cpcap_battery_get_empty(struct cpcap_battery_ddata *ddata)
{
        return cpcap_battery_get_state(ddata, CPCAP_BATTERY_STATE_EMPTY);
}

static struct cpcap_battery_state_data *
cpcap_battery_get_full(struct cpcap_battery_ddata *ddata)
{
        return cpcap_battery_get_state(ddata, CPCAP_BATTERY_STATE_FULL);
}

static int cpcap_charger_battery_temperature(struct cpcap_battery_ddata *ddata,
                                             int *value)
{
        struct iio_channel *channel;
        int error;

        channel = ddata->channels[CPCAP_BATTERY_IIO_BATTDET];
        error = iio_read_channel_processed(channel, value);
        if (error < 0) {
                if (!ignore_temperature_probe)
                        dev_warn(ddata->dev, "%s failed: %i\n", __func__, error);
                *value = CPCAP_NO_BATTERY;

                return error;
        }

        *value /= 100;

        return 0;
}

static int cpcap_battery_get_voltage(struct cpcap_battery_ddata *ddata)
{
        struct iio_channel *channel;
        int error, value = 0;

        channel = ddata->channels[CPCAP_BATTERY_IIO_VOLTAGE];
        error = iio_read_channel_processed(channel, &value);
        if (error < 0) {
                dev_warn(ddata->dev, "%s failed: %i\n", __func__, error);

                return 0;
        }

        return value * 1000;
}

static int cpcap_battery_get_current(struct cpcap_battery_ddata *ddata)
{
        struct iio_channel *channel;
        int error, value = 0;

        channel = ddata->channels[CPCAP_BATTERY_IIO_BATT_CURRENT];
        error = iio_read_channel_processed(channel, &value);
        if (error < 0) {
                dev_warn(ddata->dev, "%s failed: %i\n", __func__, error);

                return 0;
        }

        return value * 1000;
}

/**
 * cpcap_battery_cc_raw_div - calculate and divide coulomb counter μAms values
 * @ddata: device driver data
 * @sample: coulomb counter sample value
 * @accumulator: coulomb counter integrator value
 * @offset: coulomb counter offset value
 * @divider: conversion divider
 *
 * Note that cc_lsb and cc_dur values are from Motorola Linux kernel
 * function data_get_avg_curr_ua() and seem to be based on measured test
 * results. It also has the following comment:
 *
 * Adjustment factors are applied here as a temp solution per the test
 * results. Need to work out a formal solution for this adjustment.
 *
 * A coulomb counter for similar hardware seems to be documented in
 * "TWL6030 Gas Gauging Basics (Rev. A)" swca095a.pdf in chapter
 * "10 Calculating Accumulated Current". We however follow what the
 * Motorola mapphone Linux kernel is doing as there may be either a
 * TI or ST coulomb counter in the PMIC.
 */
static int cpcap_battery_cc_raw_div(struct cpcap_battery_ddata *ddata,
                                    s32 sample, s32 accumulator,
                                    s16 offset, u32 divider)
{
        s64 acc;

        if (!divider)
                return 0;

        acc = accumulator;
        acc -= (s64)sample * offset;
        acc *= ddata->cc_lsb;
        acc *= -1;
        acc = div_s64(acc, divider);

        return acc;
}

/* 3600000μAms = 1μAh */
static int cpcap_battery_cc_to_uah(struct cpcap_battery_ddata *ddata,
                                   s32 sample, s32 accumulator,
                                   s16 offset)
{
        return cpcap_battery_cc_raw_div(ddata, sample,
                                        accumulator, offset,
                                        3600000);
}

static int cpcap_battery_cc_to_ua(struct cpcap_battery_ddata *ddata,
                                  s32 sample, s32 accumulator,
                                  s16 offset)
{
        return cpcap_battery_cc_raw_div(ddata, sample,
                                        accumulator, offset,
                                        sample *
                                        CPCAP_BATTERY_CC_SAMPLE_PERIOD_MS);
}

/**
 * cpcap_battery_read_accumulated - reads cpcap coulomb counter
 * @ddata: device driver data
 * @ccd: coulomb counter values
 *
 * Based on Motorola mapphone kernel function data_read_regs().
 * Looking at the registers, the coulomb counter seems similar to
 * the coulomb counter in TWL6030. See "TWL6030 Gas Gauging Basics
 * (Rev. A) swca095a.pdf for "10 Calculating Accumulated Current".
 *
 * Note that swca095a.pdf instructs to stop the coulomb counter
 * before reading to avoid values changing. Motorola mapphone
 * Linux kernel does not do it, so let's assume they've verified
 * the data produced is correct.
 */
static int
cpcap_battery_read_accumulated(struct cpcap_battery_ddata *ddata,
                               struct cpcap_coulomb_counter_data *ccd)
{
        u16 buf[7];     /* CPCAP_REG_CCS1 to CCI */
        int error;

        ccd->sample = 0;
        ccd->accumulator = 0;
        ccd->offset = 0;
        ccd->integrator = 0;

        /* Read coulomb counter register range */
        error = regmap_bulk_read(ddata->reg, CPCAP_REG_CCS1,
                                 buf, ARRAY_SIZE(buf));
        if (error)
                return 0;

        /* Sample value CPCAP_REG_CCS1 & 2 */
        ccd->sample = (buf[1] & 0x0fff) << 16;
        ccd->sample |= buf[0];
        if (ddata->vendor == CPCAP_VENDOR_TI)
                ccd->sample = sign_extend32(24, ccd->sample);

        /* Accumulator value CPCAP_REG_CCA1 & 2 */
        ccd->accumulator = ((s16)buf[3]) << 16;
        ccd->accumulator |= buf[2];

        /*
         * Coulomb counter calibration offset is CPCAP_REG_CCM,
         * REG_CCO seems unused
         */
        ccd->offset = buf[4];
        ccd->offset = sign_extend32(ccd->offset, 9);

        /* Integrator register CPCAP_REG_CCI */
        if (ddata->vendor == CPCAP_VENDOR_TI)
                ccd->integrator = sign_extend32(buf[6], 13);
        else
                ccd->integrator = (s16)buf[6];

        return cpcap_battery_cc_to_uah(ddata,
                                       ccd->sample,
                                       ccd->accumulator,
                                       ccd->offset);
}

/**
 * cpcap_battery_cc_get_avg_current - read cpcap coulumb counter
 * @ddata: cpcap battery driver device data
 */
static int cpcap_battery_cc_get_avg_current(struct cpcap_battery_ddata *ddata)
{
        int value, acc, error;
        s32 sample;
        s16 offset;

        /* Coulomb counter integrator */
        error = regmap_read(ddata->reg, CPCAP_REG_CCI, &value);
        if (error)
                return error;

        if (ddata->vendor == CPCAP_VENDOR_TI) {
                acc = sign_extend32(value, 13);
                sample = 1;
        } else {
                acc = (s16)value;
                sample = 4;
        }

        /* Coulomb counter calibration offset  */
        error = regmap_read(ddata->reg, CPCAP_REG_CCM, &value);
        if (error)
                return error;

        offset = sign_extend32(value, 9);

        return cpcap_battery_cc_to_ua(ddata, sample, acc, offset);
}

static int cpcap_battery_get_charger_status(struct cpcap_battery_ddata *ddata,
                                            int *val)
{
        union power_supply_propval prop;
        struct power_supply *charger;
        int error;

        charger = power_supply_get_by_name("usb");
        if (!charger)
                return -ENODEV;

        error = power_supply_get_property(charger, POWER_SUPPLY_PROP_STATUS,
                                          &prop);
        if (error)
                *val = POWER_SUPPLY_STATUS_UNKNOWN;
        else
                *val = prop.intval;

        power_supply_put(charger);

        return error;
}

static bool cpcap_battery_full(struct cpcap_battery_ddata *ddata)
{
        struct cpcap_battery_state_data *state = cpcap_battery_latest(ddata);
        unsigned int vfull;
        int error, val;

        error = cpcap_battery_get_charger_status(ddata, &val);
        if (!error) {
                switch (val) {
                case POWER_SUPPLY_STATUS_DISCHARGING:
                        dev_dbg(ddata->dev, "charger disconnected\n");
                        ddata->is_full = 0;
                        break;
                case POWER_SUPPLY_STATUS_FULL:
                        dev_dbg(ddata->dev, "charger full status\n");
                        ddata->is_full = 1;
                        break;
                default:
                        break;
                }
        }

        /*
         * The full battery voltage here can be inaccurate, it's used just to
         * filter out any trickle charging events. We clear the is_full status
         * on charger disconnect above anyways.
         */
        vfull = ddata->config.bat.constant_charge_voltage_max_uv - 120000;

        if (ddata->is_full && state->voltage < vfull)
                ddata->is_full = 0;

        return ddata->is_full;
}

static bool cpcap_battery_low(struct cpcap_battery_ddata *ddata)
{
        struct cpcap_battery_state_data *state = cpcap_battery_latest(ddata);
        static bool is_low;

        if (state->current_ua > 0 && (state->voltage <= 3350000 || is_low))
                is_low = true;
        else
                is_low = false;

        return is_low;
}

static int cpcap_battery_update_status(struct cpcap_battery_ddata *ddata)
{
        struct cpcap_battery_state_data state, *latest, *previous,
                                        *empty, *full;
        ktime_t now;
        int error;

        memset(&state, 0, sizeof(state));
        now = ktime_get();

        latest = cpcap_battery_latest(ddata);
        if (latest) {
                s64 delta_ms = ktime_to_ms(ktime_sub(now, latest->time));

                if (delta_ms < CPCAP_BATTERY_CC_SAMPLE_PERIOD_MS)
                        return delta_ms;
        }

        state.time = now;
        state.voltage = cpcap_battery_get_voltage(ddata);
        state.current_ua = cpcap_battery_get_current(ddata);
        state.counter_uah = cpcap_battery_read_accumulated(ddata, &state.cc);

        error = cpcap_charger_battery_temperature(ddata,
                                                  &state.temperature);
        if (error)
                return error;

        previous = cpcap_battery_previous(ddata);
        memcpy(previous, latest, sizeof(*previous));
        memcpy(latest, &state, sizeof(*latest));

        if (cpcap_battery_full(ddata)) {
                full = cpcap_battery_get_full(ddata);
                memcpy(full, latest, sizeof(*full));

                empty = cpcap_battery_get_empty(ddata);
                if (empty->voltage && empty->voltage != -1) {
                        empty->voltage = -1;
                        ddata->charge_full =
                                empty->counter_uah - full->counter_uah;
                } else if (ddata->charge_full) {
                        empty->voltage = -1;
                        empty->counter_uah =
                                full->counter_uah + ddata->charge_full;
                }
        } else if (cpcap_battery_low(ddata)) {
                empty = cpcap_battery_get_empty(ddata);
                memcpy(empty, latest, sizeof(*empty));

                full = cpcap_battery_get_full(ddata);
                if (full->voltage) {
                        full->voltage = 0;
                        ddata->charge_full =
                                empty->counter_uah - full->counter_uah;
                }
        }

        return 0;
}

/*
 * Update battery status when cpcap-charger calls power_supply_changed().
 * This allows us to detect battery full condition before the charger
 * disconnects.
 */
static void cpcap_battery_external_power_changed(struct power_supply *psy)
{
        union power_supply_propval prop;

        power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS, &prop);
}

static enum power_supply_property cpcap_battery_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
        POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
        POWER_SUPPLY_PROP_CURRENT_AVG,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CHARGE_FULL,
        POWER_SUPPLY_PROP_CHARGE_NOW,
        POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
        POWER_SUPPLY_PROP_CHARGE_COUNTER,
        POWER_SUPPLY_PROP_POWER_NOW,
        POWER_SUPPLY_PROP_POWER_AVG,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_CAPACITY_LEVEL,
        POWER_SUPPLY_PROP_SCOPE,
        POWER_SUPPLY_PROP_TEMP,
};

static int cpcap_battery_get_property(struct power_supply *psy,
                                      enum power_supply_property psp,
                                      union power_supply_propval *val)
{
        struct cpcap_battery_ddata *ddata = power_supply_get_drvdata(psy);
        struct cpcap_battery_state_data *latest, *previous, *empty;
        u32 sample;
        s32 accumulator;
        int cached;
        s64 tmp;

        cached = cpcap_battery_update_status(ddata);
        if (cached < 0)
                return cached;

        latest = cpcap_battery_latest(ddata);
        previous = cpcap_battery_previous(ddata);

        switch (psp) {
        case POWER_SUPPLY_PROP_PRESENT:
                if (latest->temperature > CPCAP_NO_BATTERY || ignore_temperature_probe)
                        val->intval = 1;
                else
                        val->intval = 0;
                break;
        case POWER_SUPPLY_PROP_STATUS:
                if (cpcap_battery_full(ddata)) {
                        val->intval = POWER_SUPPLY_STATUS_FULL;
                        break;
                }
                if (cpcap_battery_cc_get_avg_current(ddata) < 0)
                        val->intval = POWER_SUPPLY_STATUS_CHARGING;
                else
                        val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
                break;
        case POWER_SUPPLY_PROP_TECHNOLOGY:
                val->intval = ddata->config.info.technology;
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                val->intval = cpcap_battery_get_voltage(ddata);
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
                val->intval = ddata->config.info.voltage_max_design;
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
                val->intval = ddata->config.info.voltage_min_design;
                break;
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                val->intval = ddata->config.bat.constant_charge_voltage_max_uv;
                break;
        case POWER_SUPPLY_PROP_CURRENT_AVG:
                sample = latest->cc.sample - previous->cc.sample;
                if (!sample) {
                        val->intval = cpcap_battery_cc_get_avg_current(ddata);
                        break;
                }
                accumulator = latest->cc.accumulator - previous->cc.accumulator;
                val->intval = cpcap_battery_cc_to_ua(ddata, sample,
                                                     accumulator,
                                                     latest->cc.offset);
                break;
        case POWER_SUPPLY_PROP_CURRENT_NOW:
                val->intval = latest->current_ua;
                break;
        case POWER_SUPPLY_PROP_CHARGE_COUNTER:
                val->intval = latest->counter_uah;
                break;
        case POWER_SUPPLY_PROP_POWER_NOW:
                tmp = (latest->voltage / 10000) * latest->current_ua;
                val->intval = div64_s64(tmp, 100);
                break;
        case POWER_SUPPLY_PROP_POWER_AVG:
                sample = latest->cc.sample - previous->cc.sample;
                if (!sample) {
                        tmp = cpcap_battery_cc_get_avg_current(ddata);
                        tmp *= (latest->voltage / 10000);
                        val->intval = div64_s64(tmp, 100);
                        break;
                }
                accumulator = latest->cc.accumulator - previous->cc.accumulator;
                tmp = cpcap_battery_cc_to_ua(ddata, sample, accumulator,
                                             latest->cc.offset);
                tmp *= ((latest->voltage + previous->voltage) / 20000);
                val->intval = div64_s64(tmp, 100);
                break;
        case POWER_SUPPLY_PROP_CAPACITY:
                empty = cpcap_battery_get_empty(ddata);
                if (!empty->voltage || !ddata->charge_full)
                        return -ENODATA;
                /* (ddata->charge_full / 200) is needed for rounding */
                val->intval = empty->counter_uah - latest->counter_uah +
                        ddata->charge_full / 200;
                val->intval = clamp(val->intval, 0, ddata->charge_full);
                val->intval = val->intval * 100 / ddata->charge_full;
                break;
        case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
                if (cpcap_battery_full(ddata))
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
                else if (latest->voltage >= 3750000)
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_HIGH;
                else if (latest->voltage >= 3300000)
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
                else if (latest->voltage > 3100000)
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
                else if (latest->voltage <= 3100000)
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
                else
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN;
                break;
        case POWER_SUPPLY_PROP_CHARGE_NOW:
                empty = cpcap_battery_get_empty(ddata);
                if (!empty->voltage)
                        return -ENODATA;
                val->intval = empty->counter_uah - latest->counter_uah;
                if (val->intval < 0) {
                        /* Assume invalid config if CHARGE_NOW is -20% */
                        if (ddata->charge_full && abs(val->intval) > ddata->charge_full/5) {
                                empty->voltage = 0;
                                ddata->charge_full = 0;
                                return -ENODATA;
                        }
                        val->intval = 0;
                } else if (ddata->charge_full && ddata->charge_full < val->intval) {
                        /* Assume invalid config if CHARGE_NOW exceeds CHARGE_FULL by 20% */
                        if (val->intval > (6*ddata->charge_full)/5) {
                                empty->voltage = 0;
                                ddata->charge_full = 0;
                                return -ENODATA;
                        }
                        val->intval = ddata->charge_full;
                }
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL:
                if (!ddata->charge_full)
                        return -ENODATA;
                val->intval = ddata->charge_full;
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
                val->intval = ddata->config.info.charge_full_design;
                break;
        case POWER_SUPPLY_PROP_SCOPE:
                val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
                break;
        case POWER_SUPPLY_PROP_TEMP:
                if (ignore_temperature_probe)
                        return -ENODATA;
                val->intval = latest->temperature;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int cpcap_battery_update_charger(struct cpcap_battery_ddata *ddata,
                                        int const_charge_voltage)
{
        union power_supply_propval prop;
        union power_supply_propval val;
        struct power_supply *charger;
        int error;

        charger = power_supply_get_by_name("usb");
        if (!charger)
                return -ENODEV;

        error = power_supply_get_property(charger,
                                POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
                                &prop);
        if (error)
                goto out_put;

        /* Allow charger const voltage lower than battery const voltage */
        if (const_charge_voltage > prop.intval)
                goto out_put;

        val.intval = const_charge_voltage;

        error = power_supply_set_property(charger,
                        POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
                        &val);
out_put:
        power_supply_put(charger);

        return error;
}

static int cpcap_battery_set_property(struct power_supply *psy,
                                      enum power_supply_property psp,
                                      const union power_supply_propval *val)
{
        struct cpcap_battery_ddata *ddata = power_supply_get_drvdata(psy);

        switch (psp) {
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
                if (val->intval < ddata->config.info.voltage_min_design)
                        return -EINVAL;
                if (val->intval > ddata->config.info.voltage_max_design)
                        return -EINVAL;

                ddata->config.bat.constant_charge_voltage_max_uv = val->intval;

                return cpcap_battery_update_charger(ddata, val->intval);
        case POWER_SUPPLY_PROP_CHARGE_FULL:
                if (val->intval < 0)
                        return -EINVAL;
                if (val->intval > (6*ddata->config.info.charge_full_design)/5)
                        return -EINVAL;

                ddata->charge_full = val->intval;

                return 0;
        default:
                return -EINVAL;
        }

        return 0;
}

static int cpcap_battery_property_is_writeable(struct power_supply *psy,
                                               enum power_supply_property psp)
{
        switch (psp) {
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
        case POWER_SUPPLY_PROP_CHARGE_FULL:
                return 1;
        default:
                return 0;
        }
}

static irqreturn_t cpcap_battery_irq_thread(int irq, void *data)
{
        struct cpcap_battery_ddata *ddata = data;
        struct cpcap_battery_state_data *latest;
        struct cpcap_interrupt_desc *d;

        if (!atomic_read(&ddata->active))
                return IRQ_NONE;

        list_for_each_entry(d, &ddata->irq_list, node) {
                if (irq == d->irq)
                        break;
        }

        if (list_entry_is_head(d, &ddata->irq_list, node))
                return IRQ_NONE;

        latest = cpcap_battery_latest(ddata);

        switch (d->action) {
        case CPCAP_BATTERY_IRQ_ACTION_CC_CAL_DONE:
                dev_info(ddata->dev, "Coulomb counter calibration done\n");
                break;
        case CPCAP_BATTERY_IRQ_ACTION_BATTERY_LOW:
                if (latest->current_ua >= 0)
                        dev_warn(ddata->dev, "Battery low at %imV!\n",
                                latest->voltage / 1000);
                break;
        case CPCAP_BATTERY_IRQ_ACTION_POWEROFF:
                if (latest->current_ua >= 0 && latest->voltage <= 3200000) {
                        dev_emerg(ddata->dev,
                                  "Battery empty at %imV, powering off\n",
                                  latest->voltage / 1000);
                        orderly_poweroff(true);
                }
                break;
        default:
                break;
        }

        power_supply_changed(ddata->psy);

        return IRQ_HANDLED;
}

static int cpcap_battery_init_irq(struct platform_device *pdev,
                                  struct cpcap_battery_ddata *ddata,
                                  const char *name)
{
        struct cpcap_interrupt_desc *d;
        int irq, error;

        irq = platform_get_irq_byname(pdev, name);
        if (irq < 0)
                return irq;

        error = devm_request_threaded_irq(ddata->dev, irq, NULL,
                                          cpcap_battery_irq_thread,
                                          IRQF_SHARED | IRQF_ONESHOT,
                                          name, ddata);
        if (error) {
                dev_err(ddata->dev, "could not get irq %s: %i\n",
                        name, error);

                return error;
        }

        d = devm_kzalloc(ddata->dev, sizeof(*d), GFP_KERNEL);
        if (!d)
                return -ENOMEM;

        d->name = name;
        d->irq = irq;

        if (!strncmp(name, "cccal", 5))
                d->action = CPCAP_BATTERY_IRQ_ACTION_CC_CAL_DONE;
        else if (!strncmp(name, "lowbph", 6))
                d->action = CPCAP_BATTERY_IRQ_ACTION_BATTERY_LOW;
        else if (!strncmp(name, "lowbpl", 6))
                d->action = CPCAP_BATTERY_IRQ_ACTION_POWEROFF;

        list_add(&d->node, &ddata->irq_list);

        return 0;
}

static int cpcap_battery_init_interrupts(struct platform_device *pdev,
                                         struct cpcap_battery_ddata *ddata)
{
        static const char * const cpcap_battery_irqs[] = {
                "eol", "lowbph", "lowbpl",
                "chrgcurr1", "battdetb"
        };
        int i, error;

        for (i = 0; i < ARRAY_SIZE(cpcap_battery_irqs); i++) {
                error = cpcap_battery_init_irq(pdev, ddata,
                                               cpcap_battery_irqs[i]);
                if (error)
                        return error;
        }

        /* Enable calibration interrupt if already available in dts */
        cpcap_battery_init_irq(pdev, ddata, "cccal");

        /* Enable low battery interrupts for 3.3V high and 3.1V low */
        error = regmap_update_bits(ddata->reg, CPCAP_REG_BPEOL,
                                   0xffff,
                                   CPCAP_REG_BPEOL_BIT_BATTDETEN);
        if (error)
                return error;

        return 0;
}

static int cpcap_battery_init_iio(struct cpcap_battery_ddata *ddata)
{
        const char * const names[CPCAP_BATTERY_IIO_NR] = {
                "battdetb", "battp", "chg_isense", "batti",
        };
        int error, i;

        for (i = 0; i < CPCAP_BATTERY_IIO_NR; i++) {
                ddata->channels[i] = devm_iio_channel_get(ddata->dev,
                                                          names[i]);
                if (IS_ERR(ddata->channels[i])) {
                        error = PTR_ERR(ddata->channels[i]);
                        goto out_err;
                }

                if (!ddata->channels[i]->indio_dev) {
                        error = -ENXIO;
                        goto out_err;
                }
        }

        return 0;

out_err:
        return dev_err_probe(ddata->dev, error,
                             "could not initialize VBUS or ID IIO\n");
}

/* Calibrate coulomb counter */
static int cpcap_battery_calibrate(struct cpcap_battery_ddata *ddata)
{
        int error, ccc1, value;
        unsigned long timeout;

        error = regmap_read(ddata->reg, CPCAP_REG_CCC1, &ccc1);
        if (error)
                return error;

        timeout = jiffies + msecs_to_jiffies(6000);

        /* Start calibration */
        error = regmap_update_bits(ddata->reg, CPCAP_REG_CCC1,
                                   0xffff,
                                   CPCAP_REG_CCC1_CAL_EN);
        if (error)
                goto restore;

        while (time_before(jiffies, timeout)) {
                error = regmap_read(ddata->reg, CPCAP_REG_CCC1, &value);
                if (error)
                        goto restore;

                if (!(value & CPCAP_REG_CCC1_CAL_EN))
                        break;

                error = regmap_read(ddata->reg, CPCAP_REG_CCM, &value);
                if (error)
                        goto restore;

                msleep(300);
        }

        /* Read calibration offset from CCM */
        error = regmap_read(ddata->reg, CPCAP_REG_CCM, &value);
        if (error)
                goto restore;

        dev_info(ddata->dev, "calibration done: 0x%04x\n", value);

restore:
        if (error)
                dev_err(ddata->dev, "%s: error %i\n", __func__, error);

        error = regmap_update_bits(ddata->reg, CPCAP_REG_CCC1,
                                   0xffff, ccc1);
        if (error)
                dev_err(ddata->dev, "%s: restore error %i\n",
                        __func__, error);

        return error;
}

/*
 * Based on the values from Motorola mapphone Linux kernel. In the
 * the Motorola mapphone Linux kernel tree the value for pm_cd_factor
 * is passed to the kernel via device tree. If it turns out to be
 * something device specific we can consider that too later.
 *
 * And looking at the battery full and shutdown values for the stock
 * kernel on droid 4, full is 4351000 and software initiates shutdown
 * at 3078000. The device will die around 2743000.
 */
static const struct cpcap_battery_config cpcap_battery_default_data = {
        .cd_factor = 0x3cc,
        .info.technology = POWER_SUPPLY_TECHNOLOGY_LION,
        .info.voltage_max_design = 4351000,
        .info.voltage_min_design = 3100000,
        .info.charge_full_design = 1740000,

        .bat.constant_charge_voltage_max_uv = 4200000,
};

#ifdef CONFIG_OF
static const struct of_device_id cpcap_battery_id_table[] = {
        {
                .compatible = "motorola,cpcap-battery",
                .data = &cpcap_battery_default_data,
        },
        {},
};
MODULE_DEVICE_TABLE(of, cpcap_battery_id_table);
#endif

static const struct power_supply_desc cpcap_charger_battery_desc = {
        .name           = "battery",
        .type           = POWER_SUPPLY_TYPE_BATTERY,
        .properties     = cpcap_battery_props,
        .num_properties = ARRAY_SIZE(cpcap_battery_props),
        .get_property   = cpcap_battery_get_property,
        .set_property   = cpcap_battery_set_property,
        .property_is_writeable = cpcap_battery_property_is_writeable,
        .external_power_changed = cpcap_battery_external_power_changed,
};

static int cpcap_battery_probe(struct platform_device *pdev)
{
        struct cpcap_battery_ddata *ddata;
        const struct of_device_id *match;
        struct power_supply_config psy_cfg = {};
        int error;

        match = of_match_device(of_match_ptr(cpcap_battery_id_table),
                                &pdev->dev);
        if (!match)
                return -EINVAL;

        if (!match->data) {
                dev_err(&pdev->dev, "no configuration data found\n");

                return -ENODEV;
        }

        ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
        if (!ddata)
                return -ENOMEM;

        INIT_LIST_HEAD(&ddata->irq_list);
        ddata->dev = &pdev->dev;
        memcpy(&ddata->config, match->data, sizeof(ddata->config));

        ddata->reg = dev_get_regmap(ddata->dev->parent, NULL);
        if (!ddata->reg)
                return -ENODEV;

        error = cpcap_get_vendor(ddata->dev, ddata->reg, &ddata->vendor);
        if (error)
                return error;

        switch (ddata->vendor) {
        case CPCAP_VENDOR_ST:
                ddata->cc_lsb = 95374;  /* μAms per LSB */
                break;
        case CPCAP_VENDOR_TI:
                ddata->cc_lsb = 91501;  /* μAms per LSB */
                break;
        default:
                return -EINVAL;
        }
        ddata->cc_lsb = (ddata->cc_lsb * ddata->config.cd_factor) / 1000;

        platform_set_drvdata(pdev, ddata);

        error = cpcap_battery_init_interrupts(pdev, ddata);
        if (error)
                return error;

        error = cpcap_battery_init_iio(ddata);
        if (error)
                return error;

        psy_cfg.of_node = pdev->dev.of_node;
        psy_cfg.drv_data = ddata;

        ddata->psy = devm_power_supply_register(ddata->dev,
                                                &cpcap_charger_battery_desc,
                                                &psy_cfg);
        error = PTR_ERR_OR_ZERO(ddata->psy);
        if (error) {
                dev_err(ddata->dev, "failed to register power supply\n");
                return error;
        }

        atomic_set(&ddata->active, 1);

        error = cpcap_battery_calibrate(ddata);
        if (error)
                return error;

        return 0;
}

static int cpcap_battery_remove(struct platform_device *pdev)
{
        struct cpcap_battery_ddata *ddata = platform_get_drvdata(pdev);
        int error;

        atomic_set(&ddata->active, 0);
        error = regmap_update_bits(ddata->reg, CPCAP_REG_BPEOL,
                                   0xffff, 0);
        if (error)
                dev_err(&pdev->dev, "could not disable: %i\n", error);

        return 0;
}

static struct platform_driver cpcap_battery_driver = {
        .driver = {
                .name           = "cpcap_battery",
                .of_match_table = of_match_ptr(cpcap_battery_id_table),
        },
        .probe  = cpcap_battery_probe,
        .remove = cpcap_battery_remove,
};
module_platform_driver(cpcap_battery_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
MODULE_DESCRIPTION("CPCAP PMIC Battery Driver");