// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Spreadtrum Communications Inc.

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/usb/phy.h>
#include <linux/regmap.h>
#include <linux/notifier.h>
#include <linux/of.h>

/* PMIC global registers definition */
#define SC2731_CHARGE_STATUS            0xedc
#define SC2731_CHARGE_FULL              BIT(4)
#define SC2731_MODULE_EN1               0xc0c
#define SC2731_CHARGE_EN                BIT(5)

/* SC2731 switch charger registers definition */
#define SC2731_CHG_CFG0                 0x0
#define SC2731_CHG_CFG1                 0x4
#define SC2731_CHG_CFG2                 0x8
#define SC2731_CHG_CFG3                 0xc
#define SC2731_CHG_CFG4                 0x10
#define SC2731_CHG_CFG5                 0x28

/* SC2731_CHG_CFG0 register definition */
#define SC2731_PRECHG_RNG_SHIFT         11
#define SC2731_PRECHG_RNG_MASK          GENMASK(12, 11)

#define SC2731_TERMINATION_VOL_MASK     GENMASK(2, 1)
#define SC2731_TERMINATION_VOL_SHIFT    1
#define SC2731_TERMINATION_VOL_CAL_MASK GENMASK(8, 3)
#define SC2731_TERMINATION_VOL_CAL_SHIFT        3
#define SC2731_TERMINATION_CUR_MASK     GENMASK(2, 0)

#define SC2731_CC_EN                    BIT(13)
#define SC2731_CHARGER_PD               BIT(0)

/* SC2731_CHG_CFG1 register definition */
#define SC2731_CUR_MASK                 GENMASK(5, 0)

/* SC2731_CHG_CFG5 register definition */
#define SC2731_CUR_LIMIT_SHIFT          8
#define SC2731_CUR_LIMIT_MASK           GENMASK(9, 8)

/* Default current definition (unit is mA) */
#define SC2731_CURRENT_LIMIT_100        100
#define SC2731_CURRENT_LIMIT_500        500
#define SC2731_CURRENT_LIMIT_900        900
#define SC2731_CURRENT_LIMIT_2000       2000
#define SC2731_CURRENT_PRECHG           450
#define SC2731_CURRENT_STEP             50

struct sc2731_charger_info {
        struct device *dev;
        struct regmap *regmap;
        struct usb_phy *usb_phy;
        struct notifier_block usb_notify;
        struct power_supply *psy_usb;
        struct work_struct work;
        struct mutex lock;
        bool charging;
        u32 base;
        u32 limit;
};

static void sc2731_charger_stop_charge(struct sc2731_charger_info *info)
{
        regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG0,
                           SC2731_CC_EN, 0);

        regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG0,
                           SC2731_CHARGER_PD, SC2731_CHARGER_PD);
}

static int sc2731_charger_start_charge(struct sc2731_charger_info *info)
{
        int ret;

        /* Enable charger constant current mode */
        ret = regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG0,
                                 SC2731_CC_EN, SC2731_CC_EN);
        if (ret)
                return ret;

        /* Start charging */
        return regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG0,
                                  SC2731_CHARGER_PD, 0);
}

static int sc2731_charger_set_current_limit(struct sc2731_charger_info *info,
                                            u32 limit)
{
        u32 val;

        if (limit <= SC2731_CURRENT_LIMIT_100)
                val = 0;
        else if (limit <= SC2731_CURRENT_LIMIT_500)
                val = 3;
        else if (limit <= SC2731_CURRENT_LIMIT_900)
                val = 2;
        else
                val = 1;

        return regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG5,
                                  SC2731_CUR_LIMIT_MASK,
                                  val << SC2731_CUR_LIMIT_SHIFT);
}

static int sc2731_charger_set_current(struct sc2731_charger_info *info, u32 cur)
{
        u32 val;
        int ret;

        if (cur > SC2731_CURRENT_LIMIT_2000)
                cur = SC2731_CURRENT_LIMIT_2000;
        else if (cur < SC2731_CURRENT_PRECHG)
                cur = SC2731_CURRENT_PRECHG;

        /* Calculate the step value, each step is 50 mA */
        val = (cur - SC2731_CURRENT_PRECHG) / SC2731_CURRENT_STEP;

        /* Set pre-charge current as 450 mA */
        ret = regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG0,
                                 SC2731_PRECHG_RNG_MASK,
                                 0x3 << SC2731_PRECHG_RNG_SHIFT);
        if (ret)
                return ret;

        return regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG1,
                                  SC2731_CUR_MASK, val);
}

static int sc2731_charger_get_status(struct sc2731_charger_info *info)
{
        u32 val;
        int ret;

        ret = regmap_read(info->regmap, SC2731_CHARGE_STATUS, &val);
        if (ret)
                return ret;

        if (val & SC2731_CHARGE_FULL)
                return POWER_SUPPLY_STATUS_FULL;

        return POWER_SUPPLY_STATUS_CHARGING;
}

static int sc2731_charger_get_current(struct sc2731_charger_info *info,
                                      u32 *cur)
{
        int ret;
        u32 val;

        ret = regmap_read(info->regmap, info->base + SC2731_CHG_CFG1, &val);
        if (ret)
                return ret;

        val &= SC2731_CUR_MASK;
        *cur = val * SC2731_CURRENT_STEP + SC2731_CURRENT_PRECHG;

        return 0;
}

static int sc2731_charger_get_current_limit(struct sc2731_charger_info *info,
                                            u32 *cur)
{
        int ret;
        u32 val;

        ret = regmap_read(info->regmap, info->base + SC2731_CHG_CFG5, &val);
        if (ret)
                return ret;

        val = (val & SC2731_CUR_LIMIT_MASK) >> SC2731_CUR_LIMIT_SHIFT;

        switch (val) {
        case 0:
                *cur = SC2731_CURRENT_LIMIT_100;
                break;

        case 1:
                *cur = SC2731_CURRENT_LIMIT_2000;
                break;

        case 2:
                *cur = SC2731_CURRENT_LIMIT_900;
                break;

        case 3:
                *cur = SC2731_CURRENT_LIMIT_500;
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

static int
sc2731_charger_usb_set_property(struct power_supply *psy,
                                enum power_supply_property psp,
                                const union power_supply_propval *val)
{
        struct sc2731_charger_info *info = power_supply_get_drvdata(psy);
        int ret;

        mutex_lock(&info->lock);

        if (!info->charging) {
                mutex_unlock(&info->lock);
                return -ENODEV;
        }

        switch (psp) {
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
                ret = sc2731_charger_set_current(info, val->intval / 1000);
                if (ret < 0)
                        dev_err(info->dev, "set charge current failed\n");
                break;

        case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
                ret = sc2731_charger_set_current_limit(info,
                                                       val->intval / 1000);
                if (ret < 0)
                        dev_err(info->dev, "set input current limit failed\n");
                break;

        default:
                ret = -EINVAL;
        }

        mutex_unlock(&info->lock);
        return ret;
}

static int sc2731_charger_usb_get_property(struct power_supply *psy,
                                           enum power_supply_property psp,
                                           union power_supply_propval *val)
{
        struct sc2731_charger_info *info = power_supply_get_drvdata(psy);
        int ret = 0;
        u32 cur;

        mutex_lock(&info->lock);

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                if (info->charging)
                        val->intval = sc2731_charger_get_status(info);
                else
                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                break;

        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
                if (!info->charging) {
                        val->intval = 0;
                } else {
                        ret = sc2731_charger_get_current(info, &cur);
                        if (ret)
                                goto out;

                        val->intval = cur * 1000;
                }
                break;

        case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
                if (!info->charging) {
                        val->intval = 0;
                } else {
                        ret = sc2731_charger_get_current_limit(info, &cur);
                        if (ret)
                                goto out;

                        val->intval = cur * 1000;
                }
                break;

        default:
                ret = -EINVAL;
        }

out:
        mutex_unlock(&info->lock);
        return ret;
}

static int sc2731_charger_property_is_writeable(struct power_supply *psy,
                                                enum power_supply_property psp)
{
        int ret;

        switch (psp) {
        case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
        case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
                ret = 1;
                break;

        default:
                ret = 0;
        }

        return ret;
}

static enum power_supply_property sc2731_usb_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
        POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
};

static const struct power_supply_desc sc2731_charger_desc = {
        .name                   = "sc2731_charger",
        .type                   = POWER_SUPPLY_TYPE_USB,
        .properties             = sc2731_usb_props,
        .num_properties         = ARRAY_SIZE(sc2731_usb_props),
        .get_property           = sc2731_charger_usb_get_property,
        .set_property           = sc2731_charger_usb_set_property,
        .property_is_writeable  = sc2731_charger_property_is_writeable,
};

static void sc2731_charger_work(struct work_struct *data)
{
        struct sc2731_charger_info *info =
                container_of(data, struct sc2731_charger_info, work);
        int ret;

        mutex_lock(&info->lock);

        if (info->limit > 0 && !info->charging) {
                /* set current limitation and start to charge */
                ret = sc2731_charger_set_current_limit(info, info->limit);
                if (ret)
                        goto out;

                ret = sc2731_charger_set_current(info, info->limit);
                if (ret)
                        goto out;

                ret = sc2731_charger_start_charge(info);
                if (ret)
                        goto out;

                info->charging = true;
        } else if (!info->limit && info->charging) {
                /* Stop charging */
                info->charging = false;
                sc2731_charger_stop_charge(info);
        }

out:
        mutex_unlock(&info->lock);
}

static int sc2731_charger_usb_change(struct notifier_block *nb,
                                     unsigned long limit, void *data)
{
        struct sc2731_charger_info *info =
                container_of(nb, struct sc2731_charger_info, usb_notify);

        info->limit = limit;

        schedule_work(&info->work);

        return NOTIFY_OK;
}

static int sc2731_charger_hw_init(struct sc2731_charger_info *info)
{
        struct power_supply_battery_info *bat_info;
        u32 term_currrent, term_voltage, cur_val, vol_val;
        int ret;

        /* Enable charger module */
        ret = regmap_update_bits(info->regmap, SC2731_MODULE_EN1,
                                 SC2731_CHARGE_EN, SC2731_CHARGE_EN);
        if (ret)
                return ret;

        ret = power_supply_get_battery_info(info->psy_usb, &bat_info);
        if (ret) {
                dev_warn(info->dev, "no battery information is supplied\n");

                /*
                 * If no battery information is supplied, we should set
                 * default charge termination current to 120 mA, and default
                 * charge termination voltage to 4.35V.
                 */
                cur_val = 0x2;
                vol_val = 0x1;
        } else {
                term_currrent = bat_info->charge_term_current_ua / 1000;

                if (term_currrent <= 90)
                        cur_val = 0;
                else if (term_currrent >= 265)
                        cur_val = 0x7;
                else
                        cur_val = ((term_currrent - 90) / 25) + 1;

                term_voltage = bat_info->constant_charge_voltage_max_uv / 1000;

                if (term_voltage > 4500)
                        term_voltage = 4500;

                if (term_voltage > 4200)
                        vol_val = (term_voltage - 4200) / 100;
                else
                        vol_val = 0;

                power_supply_put_battery_info(info->psy_usb, bat_info);
        }

        /* Set charge termination current */
        ret = regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG2,
                                 SC2731_TERMINATION_CUR_MASK, cur_val);
        if (ret)
                goto error;

        /* Set charge termination voltage */
        ret = regmap_update_bits(info->regmap, info->base + SC2731_CHG_CFG0,
                                 SC2731_TERMINATION_VOL_MASK |
                                 SC2731_TERMINATION_VOL_CAL_MASK,
                                 (vol_val << SC2731_TERMINATION_VOL_SHIFT) |
                                 (0x6 << SC2731_TERMINATION_VOL_CAL_SHIFT));
        if (ret)
                goto error;

        return 0;

error:
        regmap_update_bits(info->regmap, SC2731_MODULE_EN1, SC2731_CHARGE_EN, 0);
        return ret;
}

static void sc2731_charger_detect_status(struct sc2731_charger_info *info)
{
        unsigned int min, max;

        /*
         * If the USB charger status has been USB_CHARGER_PRESENT before
         * registering the notifier, we should start to charge with getting
         * the charge current.
         */
        if (info->usb_phy->chg_state != USB_CHARGER_PRESENT)
                return;

        usb_phy_get_charger_current(info->usb_phy, &min, &max);
        info->limit = min;

        schedule_work(&info->work);
}

static int sc2731_charger_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct sc2731_charger_info *info;
        struct power_supply_config charger_cfg = { };
        int ret;

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

        mutex_init(&info->lock);
        info->dev = &pdev->dev;
        INIT_WORK(&info->work, sc2731_charger_work);

        info->regmap = dev_get_regmap(pdev->dev.parent, NULL);
        if (!info->regmap) {
                dev_err(&pdev->dev, "failed to get charger regmap\n");
                return -ENODEV;
        }

        ret = of_property_read_u32(np, "reg", &info->base);
        if (ret) {
                dev_err(&pdev->dev, "failed to get register address\n");
                return -ENODEV;
        }

        charger_cfg.drv_data = info;
        charger_cfg.fwnode = dev_fwnode(&pdev->dev);
        info->psy_usb = devm_power_supply_register(&pdev->dev,
                                                   &sc2731_charger_desc,
                                                   &charger_cfg);
        if (IS_ERR(info->psy_usb)) {
                dev_err(&pdev->dev, "failed to register power supply\n");
                return PTR_ERR(info->psy_usb);
        }

        ret = sc2731_charger_hw_init(info);
        if (ret)
                return ret;

        info->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "phys", 0);
        if (IS_ERR(info->usb_phy)) {
                dev_err(&pdev->dev, "failed to find USB phy\n");
                return PTR_ERR(info->usb_phy);
        }

        info->usb_notify.notifier_call = sc2731_charger_usb_change;
        ret = usb_register_notifier(info->usb_phy, &info->usb_notify);
        if (ret) {
                dev_err(&pdev->dev, "failed to register notifier: %d\n", ret);
                return ret;
        }

        sc2731_charger_detect_status(info);

        return 0;
}

static void sc2731_charger_remove(struct platform_device *pdev)
{
        struct sc2731_charger_info *info = platform_get_drvdata(pdev);

        usb_unregister_notifier(info->usb_phy, &info->usb_notify);
}

static const struct of_device_id sc2731_charger_of_match[] = {
        { .compatible = "sprd,sc2731-charger", },
        { }
};
MODULE_DEVICE_TABLE(of, sc2731_charger_of_match);

static struct platform_driver sc2731_charger_driver = {
        .driver = {
                .name = "sc2731-charger",
                .of_match_table = sc2731_charger_of_match,
        },
        .probe = sc2731_charger_probe,
        .remove = sc2731_charger_remove,
};

module_platform_driver(sc2731_charger_driver);

MODULE_DESCRIPTION("Spreadtrum SC2731 Charger Driver");
MODULE_LICENSE("GPL v2");