// SPDX-License-Identifier: GPL-2.0+
//
// max14577_charger.c - Battery charger driver for the Maxim 14577/77836
//
// Copyright (C) 2013,2014 Samsung Electronics
// Krzysztof Kozlowski <krzk@kernel.org>

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/mfd/max14577-private.h>
#include <linux/mfd/max14577.h>

struct max14577_charger {
        struct device           *dev;
        struct max14577         *max14577;
        struct power_supply     *charger;

        struct max14577_charger_platform_data   *pdata;
};

/*
 * Helper function for mapping values of STATUS2/CHGTYP register on max14577
 * and max77836 chipsets to enum maxim_muic_charger_type.
 */
static enum max14577_muic_charger_type maxim_get_charger_type(
                enum maxim_device_type dev_type, u8 val) {
        switch (val) {
        case MAX14577_CHARGER_TYPE_NONE:
        case MAX14577_CHARGER_TYPE_USB:
        case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT:
        case MAX14577_CHARGER_TYPE_DEDICATED_CHG:
        case MAX14577_CHARGER_TYPE_SPECIAL_500MA:
        case MAX14577_CHARGER_TYPE_SPECIAL_1A:
                return val;
        case MAX14577_CHARGER_TYPE_DEAD_BATTERY:
        case MAX14577_CHARGER_TYPE_RESERVED:
                if (dev_type == MAXIM_DEVICE_TYPE_MAX77836)
                        val |= 0x8;
                return val;
        default:
                WARN_ONCE(1, "max14577: Unsupported chgtyp register value 0x%02x", val);
                return val;
        }
}

static int max14577_get_charger_state(struct max14577_charger *chg, int *val)
{
        struct regmap *rmap = chg->max14577->regmap;
        int ret;
        u8 reg_data;

        /*
         * Charging occurs only if:
         *  - CHGCTRL2/MBCHOSTEN == 1
         *  - STATUS2/CGMBC == 1
         *
         * TODO:
         *  - handle FULL after Top-off timer (EOC register may be off
         *    and the charger won't be charging although MBCHOSTEN is on)
         *  - handle properly dead-battery charging (respect timer)
         *  - handle timers (fast-charge and prequal) /MBCCHGERR/
         */
        ret = max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
        if (ret < 0)
                goto out;

        if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0) {
                *val = POWER_SUPPLY_STATUS_DISCHARGING;
                goto out;
        }

        ret = max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
        if (ret < 0)
                goto out;

        if (reg_data & STATUS3_CGMBC_MASK) {
                /* Charger or USB-cable is connected */
                if (reg_data & STATUS3_EOC_MASK)
                        *val = POWER_SUPPLY_STATUS_FULL;
                else
                        *val = POWER_SUPPLY_STATUS_CHARGING;
                goto out;
        }

        *val = POWER_SUPPLY_STATUS_DISCHARGING;

out:
        return ret;
}

/*
 * Supported charge types:
 *  - POWER_SUPPLY_CHARGE_TYPE_NONE
 *  - POWER_SUPPLY_CHARGE_TYPE_FAST
 */
static int max14577_get_charge_type(struct max14577_charger *chg, int *val)
{
        int ret, charging;

        /*
         * TODO: CHARGE_TYPE_TRICKLE (VCHGR_RC or EOC)?
         * As spec says:
         * [after reaching EOC interrupt]
         * "When the battery is fully charged, the 30-minute (typ)
         *  top-off timer starts. The device continues to trickle
         *  charge the battery until the top-off timer runs out."
         */
        ret = max14577_get_charger_state(chg, &charging);
        if (ret < 0)
                return ret;

        if (charging == POWER_SUPPLY_STATUS_CHARGING)
                *val = POWER_SUPPLY_CHARGE_TYPE_FAST;
        else
                *val = POWER_SUPPLY_CHARGE_TYPE_NONE;

        return 0;
}

static int max14577_get_online(struct max14577_charger *chg, int *val)
{
        struct regmap *rmap = chg->max14577->regmap;
        u8 reg_data;
        int ret;
        enum max14577_muic_charger_type chg_type;

        ret = max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
        if (ret < 0)
                return ret;

        reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
        chg_type = maxim_get_charger_type(chg->max14577->dev_type, reg_data);
        switch (chg_type) {
        case MAX14577_CHARGER_TYPE_USB:
        case MAX14577_CHARGER_TYPE_DEDICATED_CHG:
        case MAX14577_CHARGER_TYPE_SPECIAL_500MA:
        case MAX14577_CHARGER_TYPE_SPECIAL_1A:
        case MAX14577_CHARGER_TYPE_DEAD_BATTERY:
        case MAX77836_CHARGER_TYPE_SPECIAL_BIAS:
                *val = 1;
                break;
        case MAX14577_CHARGER_TYPE_NONE:
        case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT:
        case MAX14577_CHARGER_TYPE_RESERVED:
        case MAX77836_CHARGER_TYPE_RESERVED:
        default:
                *val = 0;
        }

        return 0;
}

/*
 * Supported health statuses:
 *  - POWER_SUPPLY_HEALTH_DEAD
 *  - POWER_SUPPLY_HEALTH_OVERVOLTAGE
 *  - POWER_SUPPLY_HEALTH_GOOD
 */
static int max14577_get_battery_health(struct max14577_charger *chg, int *val)
{
        struct regmap *rmap = chg->max14577->regmap;
        int ret;
        u8 reg_data;
        enum max14577_muic_charger_type chg_type;

        ret = max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
        if (ret < 0)
                goto out;

        reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
        chg_type = maxim_get_charger_type(chg->max14577->dev_type, reg_data);
        if (chg_type == MAX14577_CHARGER_TYPE_DEAD_BATTERY) {
                *val = POWER_SUPPLY_HEALTH_DEAD;
                goto out;
        }

        ret = max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
        if (ret < 0)
                goto out;

        if (reg_data & STATUS3_OVP_MASK) {
                *val = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
                goto out;
        }

        /* Not dead, not overvoltage */
        *val = POWER_SUPPLY_HEALTH_GOOD;

out:
        return ret;
}

/*
 * Always returns 1.
 * The max14577 chip doesn't report any status of battery presence.
 * Lets assume that it will always be used with some battery.
 */
static int max14577_get_present(struct max14577_charger *chg, int *val)
{
        *val = 1;

        return 0;
}

static int max14577_set_fast_charge_timer(struct max14577_charger *chg,
                unsigned long hours)
{
        u8 reg_data;

        switch (hours) {
        case 5 ... 7:
                reg_data = hours - 3;
                break;
        case 0:
                /* Disable */
                reg_data = 0x7;
                break;
        default:
                dev_err(chg->dev, "Wrong value for Fast-Charge Timer: %lu\n",
                                hours);
                return -EINVAL;
        }
        reg_data <<= CHGCTRL1_TCHW_SHIFT;

        return max14577_update_reg(chg->max14577->regmap,
                        MAX14577_REG_CHGCTRL1, CHGCTRL1_TCHW_MASK, reg_data);
}

static int max14577_init_constant_voltage(struct max14577_charger *chg,
                unsigned int uvolt)
{
        u8 reg_data;

        if (uvolt < MAXIM_CHARGER_CONSTANT_VOLTAGE_MIN ||
                        uvolt > MAXIM_CHARGER_CONSTANT_VOLTAGE_MAX)
                return -EINVAL;

        if (uvolt == 4200000)
                reg_data = 0x0;
        else if (uvolt == MAXIM_CHARGER_CONSTANT_VOLTAGE_MAX)
                reg_data = 0x1f;
        else if (uvolt <= 4280000) {
                unsigned int val = uvolt;

                val -= MAXIM_CHARGER_CONSTANT_VOLTAGE_MIN;
                val /= MAXIM_CHARGER_CONSTANT_VOLTAGE_STEP;
                if (uvolt <= 4180000)
                        reg_data = 0x1 + val;
                else
                        reg_data = val; /* Fix for gap between 4.18V and 4.22V */
        } else
                return -EINVAL;

        reg_data <<= CHGCTRL3_MBCCVWRC_SHIFT;

        return max14577_write_reg(chg->max14577->regmap,
                        MAX14577_CHG_REG_CHG_CTRL3, reg_data);
}

static int max14577_init_eoc(struct max14577_charger *chg,
                unsigned int uamp)
{
        unsigned int current_bits;
        u8 reg_data;

        switch (chg->max14577->dev_type) {
        case MAXIM_DEVICE_TYPE_MAX77836:
                if (uamp < 5000)
                        return -EINVAL; /* Requested current is too low */

                if (uamp >= 7500 && uamp < 10000)
                        current_bits = 0x0;
                else if (uamp <= 50000) {
                        /* <5000, 7499> and <10000, 50000> */
                        current_bits = uamp / 5000;
                } else {
                        uamp = min(uamp, 100000U) - 50000U;
                        current_bits = 0xa + uamp / 10000;
                }
                break;

        case MAXIM_DEVICE_TYPE_MAX14577:
        default:
                if (uamp < MAX14577_CHARGER_EOC_CURRENT_LIMIT_MIN)
                        return -EINVAL; /* Requested current is too low */

                uamp = min(uamp, MAX14577_CHARGER_EOC_CURRENT_LIMIT_MAX);
                uamp -= MAX14577_CHARGER_EOC_CURRENT_LIMIT_MIN;
                current_bits = uamp / MAX14577_CHARGER_EOC_CURRENT_LIMIT_STEP;
                break;
        }

        reg_data = current_bits << CHGCTRL5_EOCS_SHIFT;

        return max14577_update_reg(chg->max14577->regmap,
                        MAX14577_CHG_REG_CHG_CTRL5, CHGCTRL5_EOCS_MASK,
                        reg_data);
}

static int max14577_init_fast_charge(struct max14577_charger *chg,
                unsigned int uamp)
{
        u8 reg_data;
        int ret;
        const struct maxim_charger_current *limits =
                &maxim_charger_currents[chg->max14577->dev_type];

        ret = maxim_charger_calc_reg_current(limits, uamp, uamp, &reg_data);
        if (ret) {
                dev_err(chg->dev, "Wrong value for fast charge: %u\n", uamp);
                return ret;
        }

        return max14577_update_reg(chg->max14577->regmap,
                        MAX14577_CHG_REG_CHG_CTRL4,
                        CHGCTRL4_MBCICHWRCL_MASK | CHGCTRL4_MBCICHWRCH_MASK,
                        reg_data);
}

/*
 * Sets charger registers to proper and safe default values.
 * Some of these values are equal to defaults in MAX14577E
 * data sheet but there are minor differences.
 */
static int max14577_charger_reg_init(struct max14577_charger *chg)
{
        struct regmap *rmap = chg->max14577->regmap;
        u8 reg_data;
        int ret;

        /*
         * Charger-Type Manual Detection, default off (set CHGTYPMAN to 0)
         * Charger-Detection Enable, default on (set CHGDETEN to 1)
         * Combined mask of CHGDETEN and CHGTYPMAN will zero the CHGTYPMAN bit
         */
        reg_data = 0x1 << CDETCTRL1_CHGDETEN_SHIFT;
        max14577_update_reg(rmap, MAX14577_REG_CDETCTRL1,
                        CDETCTRL1_CHGDETEN_MASK | CDETCTRL1_CHGTYPMAN_MASK,
                        reg_data);

        /*
         * Wall-Adapter Rapid Charge, default on
         * Battery-Charger, default on
         */
        reg_data = 0x1 << CHGCTRL2_VCHGR_RC_SHIFT;
        reg_data |= 0x1 << CHGCTRL2_MBCHOSTEN_SHIFT;
        max14577_write_reg(rmap, MAX14577_REG_CHGCTRL2, reg_data);

        /* Auto Charging Stop, default off */
        reg_data = 0x0 << CHGCTRL6_AUTOSTOP_SHIFT;
        max14577_write_reg(rmap, MAX14577_REG_CHGCTRL6, reg_data);

        ret = max14577_init_constant_voltage(chg, chg->pdata->constant_uvolt);
        if (ret)
                return ret;

        ret = max14577_init_eoc(chg, chg->pdata->eoc_uamp);
        if (ret)
                return ret;

        ret = max14577_init_fast_charge(chg, chg->pdata->fast_charge_uamp);
        if (ret)
                return ret;

        ret = max14577_set_fast_charge_timer(chg,
                        MAXIM_CHARGER_FAST_CHARGE_TIMER_DEFAULT);
        if (ret)
                return ret;

        /* Initialize Overvoltage-Protection Threshold */
        switch (chg->pdata->ovp_uvolt) {
        case 7500000:
                reg_data = 0x0;
                break;
        case 6000000:
        case 6500000:
        case 7000000:
                reg_data = 0x1 + (chg->pdata->ovp_uvolt - 6000000) / 500000;
                break;
        default:
                dev_err(chg->dev, "Wrong value for OVP: %u\n",
                                chg->pdata->ovp_uvolt);
                return -EINVAL;
        }
        reg_data <<= CHGCTRL7_OTPCGHCVS_SHIFT;
        max14577_write_reg(rmap, MAX14577_REG_CHGCTRL7, reg_data);

        return 0;
}

/* Support property from charger */
static enum power_supply_property max14577_charger_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_CHARGE_TYPE,
        POWER_SUPPLY_PROP_HEALTH,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
};

static const char * const model_names[] = {
        [MAXIM_DEVICE_TYPE_UNKNOWN]     = "MAX14577-like",
        [MAXIM_DEVICE_TYPE_MAX14577]    = "MAX14577",
        [MAXIM_DEVICE_TYPE_MAX77836]    = "MAX77836",
};
static const char *manufacturer = "Maxim Integrated";

static int max14577_charger_get_property(struct power_supply *psy,
                            enum power_supply_property psp,
                            union power_supply_propval *val)
{
        struct max14577_charger *chg = power_supply_get_drvdata(psy);
        int ret = 0;

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                ret = max14577_get_charger_state(chg, &val->intval);
                break;
        case POWER_SUPPLY_PROP_CHARGE_TYPE:
                ret = max14577_get_charge_type(chg, &val->intval);
                break;
        case POWER_SUPPLY_PROP_HEALTH:
                ret = max14577_get_battery_health(chg, &val->intval);
                break;
        case POWER_SUPPLY_PROP_PRESENT:
                ret = max14577_get_present(chg, &val->intval);
                break;
        case POWER_SUPPLY_PROP_ONLINE:
                ret = max14577_get_online(chg, &val->intval);
                break;
        case POWER_SUPPLY_PROP_MODEL_NAME:
                BUILD_BUG_ON(ARRAY_SIZE(model_names) != MAXIM_DEVICE_TYPE_NUM);
                val->strval = model_names[chg->max14577->dev_type];
                break;
        case POWER_SUPPLY_PROP_MANUFACTURER:
                val->strval = manufacturer;
                break;
        default:
                return -EINVAL;
        }

        return ret;
}

static const struct power_supply_desc max14577_charger_desc = {
        .name = "max14577-charger",
        .type = POWER_SUPPLY_TYPE_BATTERY,
        .properties = max14577_charger_props,
        .num_properties = ARRAY_SIZE(max14577_charger_props),
        .get_property = max14577_charger_get_property,
};

#ifdef CONFIG_OF
static struct max14577_charger_platform_data *max14577_charger_dt_init(
                struct platform_device *pdev)
{
        struct max14577_charger_platform_data *pdata;
        struct device_node *np = pdev->dev.of_node;
        int ret;

        if (!np) {
                dev_err(&pdev->dev, "No charger OF node\n");
                return ERR_PTR(-EINVAL);
        }

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

        ret = of_property_read_u32(np, "maxim,constant-uvolt",
                        &pdata->constant_uvolt);
        if (ret) {
                dev_err(&pdev->dev, "Cannot parse maxim,constant-uvolt field from DT\n");
                return ERR_PTR(ret);
        }

        ret = of_property_read_u32(np, "maxim,fast-charge-uamp",
                        &pdata->fast_charge_uamp);
        if (ret) {
                dev_err(&pdev->dev, "Cannot parse maxim,fast-charge-uamp field from DT\n");
                return ERR_PTR(ret);
        }

        ret = of_property_read_u32(np, "maxim,eoc-uamp", &pdata->eoc_uamp);
        if (ret) {
                dev_err(&pdev->dev, "Cannot parse maxim,eoc-uamp field from DT\n");
                return ERR_PTR(ret);
        }

        ret = of_property_read_u32(np, "maxim,ovp-uvolt", &pdata->ovp_uvolt);
        if (ret) {
                dev_err(&pdev->dev, "Cannot parse maxim,ovp-uvolt field from DT\n");
                return ERR_PTR(ret);
        }

        return pdata;
}
#else /* CONFIG_OF */
static struct max14577_charger_platform_data *max14577_charger_dt_init(
                struct platform_device *pdev)
{
        return ERR_PTR(-ENODATA);
}
#endif /* CONFIG_OF */

static ssize_t show_fast_charge_timer(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct max14577_charger *chg = dev_get_drvdata(dev);
        u8 reg_data;
        int ret;
        unsigned int val;

        ret = max14577_read_reg(chg->max14577->regmap, MAX14577_REG_CHGCTRL1,
                        &reg_data);
        if (ret)
                return ret;

        reg_data &= CHGCTRL1_TCHW_MASK;
        reg_data >>= CHGCTRL1_TCHW_SHIFT;
        switch (reg_data) {
        case 0x2 ... 0x4:
                val = reg_data + 3;
                break;
        case 0x7:
                val = 0;
                break;
        default:
                val = 5;
                break;
        }

        return sysfs_emit(buf, "%u\n", val);
}

static ssize_t store_fast_charge_timer(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct max14577_charger *chg = dev_get_drvdata(dev);
        unsigned long val;
        int ret;

        ret = kstrtoul(buf, 10, &val);
        if (ret)
                return ret;

        ret = max14577_set_fast_charge_timer(chg, val);
        if (ret)
                return ret;

        return count;
}

static DEVICE_ATTR(fast_charge_timer, S_IRUGO | S_IWUSR,
                show_fast_charge_timer, store_fast_charge_timer);

static int max14577_charger_probe(struct platform_device *pdev)
{
        struct max14577_charger *chg;
        struct power_supply_config psy_cfg = {};
        struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
        int ret;

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

        platform_set_drvdata(pdev, chg);
        chg->dev = &pdev->dev;
        chg->max14577 = max14577;

        chg->pdata = max14577_charger_dt_init(pdev);
        if (IS_ERR(chg->pdata))
                return PTR_ERR(chg->pdata);

        ret = max14577_charger_reg_init(chg);
        if (ret)
                return ret;

        ret = device_create_file(&pdev->dev, &dev_attr_fast_charge_timer);
        if (ret) {
                dev_err(&pdev->dev, "failed: create sysfs entry\n");
                return ret;
        }

        psy_cfg.drv_data = chg;
        chg->charger = devm_power_supply_register(&pdev->dev,
                                                  &max14577_charger_desc,
                                                  &psy_cfg);
        if (IS_ERR(chg->charger)) {
                dev_err(&pdev->dev, "failed: power supply register\n");
                ret = PTR_ERR(chg->charger);
                goto err;
        }

        /* Check for valid values for charger */
        BUILD_BUG_ON(MAX14577_CHARGER_EOC_CURRENT_LIMIT_MIN +
                        MAX14577_CHARGER_EOC_CURRENT_LIMIT_STEP * 0xf !=
                        MAX14577_CHARGER_EOC_CURRENT_LIMIT_MAX);
        return 0;

err:
        device_remove_file(&pdev->dev, &dev_attr_fast_charge_timer);

        return ret;
}

static void max14577_charger_remove(struct platform_device *pdev)
{
        device_remove_file(&pdev->dev, &dev_attr_fast_charge_timer);
}

static const struct platform_device_id max14577_charger_id[] = {
        { "max14577-charger", MAXIM_DEVICE_TYPE_MAX14577, },
        { "max77836-charger", MAXIM_DEVICE_TYPE_MAX77836, },
        { }
};
MODULE_DEVICE_TABLE(platform, max14577_charger_id);

static const struct of_device_id of_max14577_charger_dt_match[] = {
        { .compatible = "maxim,max14577-charger",
          .data = (void *)MAXIM_DEVICE_TYPE_MAX14577, },
        { .compatible = "maxim,max77836-charger",
          .data = (void *)MAXIM_DEVICE_TYPE_MAX77836, },
        { },
};
MODULE_DEVICE_TABLE(of, of_max14577_charger_dt_match);

static struct platform_driver max14577_charger_driver = {
        .driver = {
                .name   = "max14577-charger",
                .of_match_table = of_max14577_charger_dt_match,
        },
        .probe          = max14577_charger_probe,
        .remove         = max14577_charger_remove,
        .id_table       = max14577_charger_id,
};
module_platform_driver(max14577_charger_driver);

MODULE_AUTHOR("Krzysztof Kozlowski <krzk@kernel.org>");
MODULE_DESCRIPTION("Maxim 14577/77836 charger driver");
MODULE_LICENSE("GPL");