// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2023 Richtek Technology Corp.
 *
 * Authors:
 *   Alice Chen <alice_chen@richtek.com>
 *   ChiYuan Huang <cy_huang@richtek.com>
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/led-class-flash.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>

#include <media/v4l2-flash-led-class.h>

enum {
        MT6370_LED_FLASH1 = 0,
        MT6370_LED_FLASH2,
        MT6370_MAX_LEDS
};

/* Virtual definition for multicolor */

#define MT6370_REG_FLEDEN               0x17E
#define MT6370_REG_STRBTO               0x173
#define MT6370_REG_CHGSTAT2             0x1D1
#define MT6370_REG_FLEDSTAT1            0x1D9
#define MT6370_REG_FLEDISTRB(_id)       (0x174 + 4 * (_id))
#define MT6370_REG_FLEDITOR(_id)        (0x175 + 4 * (_id))
#define MT6370_ITORCH_MASK              GENMASK(4, 0)
#define MT6370_ISTROBE_MASK             GENMASK(6, 0)
#define MT6370_STRBTO_MASK              GENMASK(6, 0)
#define MT6370_TORCHEN_MASK             BIT(3)
#define MT6370_STROBEN_MASK             BIT(2)
#define MT6370_FLCSEN_MASK(_id)         BIT(MT6370_LED_FLASH2 - (_id))
#define MT6370_FLCSEN_MASK_ALL          GENMASK(1, 0)
#define MT6370_FLEDCHGVINOVP_MASK       BIT(3)
#define MT6370_FLED1STRBTO_MASK         BIT(11)
#define MT6370_FLED2STRBTO_MASK         BIT(10)
#define MT6370_FLED1STRB_MASK           BIT(9)
#define MT6370_FLED2STRB_MASK           BIT(8)
#define MT6370_FLED1SHORT_MASK          BIT(7)
#define MT6370_FLED2SHORT_MASK          BIT(6)
#define MT6370_FLEDLVF_MASK             BIT(3)

#define MT6370_LED_JOINT                2
#define MT6370_RANGE_FLED_REG           4
#define MT6370_ITORCH_MIN_uA            25000
#define MT6370_ITORCH_STEP_uA           12500
#define MT6370_ITORCH_MAX_uA            400000
#define MT6370_ITORCH_DOUBLE_MAX_uA     800000
#define MT6370_ISTRB_MIN_uA             50000
#define MT6370_ISTRB_STEP_uA            12500
#define MT6370_ISTRB_MAX_uA             1500000
#define MT6370_ISTRB_DOUBLE_MAX_uA      3000000
#define MT6370_STRBTO_MIN_US            64000
#define MT6370_STRBTO_STEP_US           32000
#define MT6370_STRBTO_MAX_US            2432000

#define to_mt6370_led(ptr, member) container_of(ptr, struct mt6370_led, member)

struct mt6370_led {
        struct led_classdev_flash flash;
        struct v4l2_flash *v4l2_flash;
        struct mt6370_priv *priv;
        u8 led_no;
};

struct mt6370_priv {
        struct regmap *regmap;
        struct mutex lock;
        unsigned int fled_strobe_used;
        unsigned int fled_torch_used;
        unsigned int leds_active;
        unsigned int leds_count;
        struct mt6370_led leds[] __counted_by(leds_count);
};

static int mt6370_torch_brightness_set(struct led_classdev *lcdev, enum led_brightness level)
{
        struct mt6370_led *led = to_mt6370_led(lcdev, flash.led_cdev);
        struct mt6370_priv *priv = led->priv;
        u32 led_enable_mask = led->led_no == MT6370_LED_JOINT ? MT6370_FLCSEN_MASK_ALL :
                              MT6370_FLCSEN_MASK(led->led_no);
        u32 enable_mask = MT6370_TORCHEN_MASK | led_enable_mask;
        u32 val = level ? led_enable_mask : 0;
        u32 curr;
        int ret, i;

        mutex_lock(&priv->lock);

        /*
         * There is only one set of flash control logic, and this flag is used to check if 'strobe'
         * is currently being used.
         */
        if (priv->fled_strobe_used) {
                dev_warn(lcdev->dev, "Please disable strobe first [%d]\n", priv->fled_strobe_used);
                ret = -EBUSY;
                goto unlock;
        }

        if (level)
                curr = priv->fled_torch_used | BIT(led->led_no);
        else
                curr = priv->fled_torch_used & ~BIT(led->led_no);

        if (curr)
                val |= MT6370_TORCHEN_MASK;

        if (level) {
                level -= 1;
                if (led->led_no == MT6370_LED_JOINT) {
                        u32 flevel[MT6370_MAX_LEDS];

                        /*
                         * There're two flash channels in MT6370. If joint flash output is used,
                         * torch current will be averaged output from both channels.
                         */
                        flevel[0] = level / 2;
                        flevel[1] = level - flevel[0];
                        for (i = 0; i < MT6370_MAX_LEDS; i++) {
                                ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDITOR(i),
                                                         MT6370_ITORCH_MASK, flevel[i]);
                                if (ret)
                                        goto unlock;
                        }
                } else {
                        ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDITOR(led->led_no),
                                                 MT6370_ITORCH_MASK, level);
                        if (ret)
                                goto unlock;
                }
        }

        ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN, enable_mask, val);
        if (ret)
                goto unlock;

        priv->fled_torch_used = curr;

unlock:
        mutex_unlock(&priv->lock);
        return ret;
}

static int mt6370_flash_brightness_set(struct led_classdev_flash *fl_cdev, u32 brightness)
{
        /*
         * Because of the current spikes when turning on the flash, the brightness should be kept
         * by the LED framework. This empty function is used to prevent checking failure when
         * led_classdev_flash registers ops.
         */
        return 0;
}

static int _mt6370_flash_brightness_set(struct led_classdev_flash *fl_cdev, u32 brightness)
{
        struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
        struct mt6370_priv *priv = led->priv;
        struct led_flash_setting *setting = &fl_cdev->brightness;
        u32 val = (brightness - setting->min) / setting->step;
        int ret, i;

        if (led->led_no == MT6370_LED_JOINT) {
                u32 flevel[MT6370_MAX_LEDS];

                /*
                 * There're two flash channels in MT6370. If joint flash output is used, storbe
                 * current will be averaged output from both channels.
                 */
                flevel[0] = val / 2;
                flevel[1] = val - flevel[0];
                for (i = 0; i < MT6370_MAX_LEDS; i++) {
                        ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDISTRB(i),
                                                 MT6370_ISTROBE_MASK, flevel[i]);
                        if (ret)
                                break;
                }
        } else {
                ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDISTRB(led->led_no),
                                         MT6370_ISTROBE_MASK, val);
        }

        return ret;
}

static int mt6370_strobe_set(struct led_classdev_flash *fl_cdev, bool state)
{
        struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
        struct mt6370_priv *priv = led->priv;
        struct led_classdev *lcdev = &fl_cdev->led_cdev;
        struct led_flash_setting *s = &fl_cdev->brightness;
        u32 led_enable_mask = led->led_no == MT6370_LED_JOINT ? MT6370_FLCSEN_MASK_ALL :
                              MT6370_FLCSEN_MASK(led->led_no);
        u32 enable_mask = MT6370_STROBEN_MASK | led_enable_mask;
        u32 val = state ? led_enable_mask : 0;
        u32 curr;
        int ret;

        mutex_lock(&priv->lock);

        /*
         * There is only one set of flash control logic, and this flag is used to check if 'torch'
         * is currently being used.
         */
        if (priv->fled_torch_used) {
                dev_warn(lcdev->dev, "Please disable torch first [0x%x]\n", priv->fled_torch_used);
                ret = -EBUSY;
                goto unlock;
        }

        if (state)
                curr = priv->fled_strobe_used | BIT(led->led_no);
        else
                curr = priv->fled_strobe_used & ~BIT(led->led_no);

        if (curr)
                val |= MT6370_STROBEN_MASK;

        ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN, enable_mask, val);
        if (ret) {
                dev_err(lcdev->dev, "[%d] control current source %d fail\n", led->led_no, state);
                goto unlock;
        }

        /*
         * If the flash needs to turn on, configure the flash current to ramp up to the setting
         * value. Otherwise, always revert to the minimum one.
         */
        ret = _mt6370_flash_brightness_set(fl_cdev, state ? s->val : s->min);
        if (ret) {
                dev_err(lcdev->dev, "[%d] Failed to set brightness\n", led->led_no);
                goto unlock;
        }

        /*
         * For the flash to turn on/off, we must wait for HW ramping up/down time 5ms/500us to
         * prevent the unexpected problem.
         */
        if (!priv->fled_strobe_used && curr)
                usleep_range(5000, 6000);
        else if (priv->fled_strobe_used && !curr)
                usleep_range(500, 600);

        priv->fled_strobe_used = curr;

unlock:
        mutex_unlock(&priv->lock);
        return ret;
}

static int mt6370_strobe_get(struct led_classdev_flash *fl_cdev, bool *state)
{
        struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
        struct mt6370_priv *priv = led->priv;

        mutex_lock(&priv->lock);
        *state = !!(priv->fled_strobe_used & BIT(led->led_no));
        mutex_unlock(&priv->lock);

        return 0;
}

static int mt6370_timeout_set(struct led_classdev_flash *fl_cdev, u32 timeout)
{
        struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
        struct mt6370_priv *priv = led->priv;
        struct led_flash_setting *s = &fl_cdev->timeout;
        u32 val = (timeout - s->min) / s->step;

        return regmap_update_bits(priv->regmap, MT6370_REG_STRBTO, MT6370_STRBTO_MASK, val);
}

static int mt6370_fault_get(struct led_classdev_flash *fl_cdev, u32 *fault)
{
        struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
        struct mt6370_priv *priv = led->priv;
        u16 fled_stat;
        unsigned int chg_stat, strobe_timeout_mask, fled_short_mask;
        u32 rfault = 0;
        int ret;

        ret = regmap_read(priv->regmap, MT6370_REG_CHGSTAT2, &chg_stat);
        if (ret)
                return ret;

        ret = regmap_raw_read(priv->regmap, MT6370_REG_FLEDSTAT1, &fled_stat, sizeof(fled_stat));
        if (ret)
                return ret;

        switch (led->led_no) {
        case MT6370_LED_FLASH1:
                strobe_timeout_mask = MT6370_FLED1STRBTO_MASK;
                fled_short_mask = MT6370_FLED1SHORT_MASK;
                break;

        case MT6370_LED_FLASH2:
                strobe_timeout_mask = MT6370_FLED2STRBTO_MASK;
                fled_short_mask = MT6370_FLED2SHORT_MASK;
                break;

        case MT6370_LED_JOINT:
                strobe_timeout_mask = MT6370_FLED1STRBTO_MASK | MT6370_FLED2STRBTO_MASK;
                fled_short_mask = MT6370_FLED1SHORT_MASK | MT6370_FLED2SHORT_MASK;
                break;
        default:
                return -EINVAL;
        }

        if (chg_stat & MT6370_FLEDCHGVINOVP_MASK)
                rfault |= LED_FAULT_INPUT_VOLTAGE;

        if (fled_stat & strobe_timeout_mask)
                rfault |= LED_FAULT_TIMEOUT;

        if (fled_stat & fled_short_mask)
                rfault |= LED_FAULT_SHORT_CIRCUIT;

        if (fled_stat & MT6370_FLEDLVF_MASK)
                rfault |= LED_FAULT_UNDER_VOLTAGE;

        *fault = rfault;
        return ret;
}

static const struct led_flash_ops mt6370_flash_ops = {
        .flash_brightness_set = mt6370_flash_brightness_set,
        .strobe_set = mt6370_strobe_set,
        .strobe_get = mt6370_strobe_get,
        .timeout_set = mt6370_timeout_set,
        .fault_get = mt6370_fault_get,
};

#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
static int mt6370_flash_external_strobe_set(struct v4l2_flash *v4l2_flash,
                                            bool enable)
{
        struct led_classdev_flash *flash = v4l2_flash->fled_cdev;
        struct mt6370_led *led = to_mt6370_led(flash, flash);
        struct mt6370_priv *priv = led->priv;
        u32 mask = led->led_no == MT6370_LED_JOINT ? MT6370_FLCSEN_MASK_ALL :
                   MT6370_FLCSEN_MASK(led->led_no);
        u32 val = enable ? mask : 0;
        int ret;

        mutex_lock(&priv->lock);

        ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN, mask, val);
        if (ret)
                goto unlock;

        if (enable)
                priv->fled_strobe_used |= BIT(led->led_no);
        else
                priv->fled_strobe_used &= ~BIT(led->led_no);

unlock:
        mutex_unlock(&priv->lock);
        return ret;
}

static const struct v4l2_flash_ops v4l2_flash_ops = {
        .external_strobe_set = mt6370_flash_external_strobe_set,
};

static void mt6370_init_v4l2_flash_config(struct mt6370_led *led, struct v4l2_flash_config *cfg)
{
        struct led_classdev *lcdev;
        struct led_flash_setting *s = &cfg->intensity;

        lcdev = &led->flash.led_cdev;

        s->min = MT6370_ITORCH_MIN_uA;
        s->step = MT6370_ITORCH_STEP_uA;
        s->val = s->max = s->min + (lcdev->max_brightness - 1) * s->step;

        cfg->has_external_strobe = 1;
        strscpy(cfg->dev_name, dev_name(lcdev->dev), sizeof(cfg->dev_name));

        cfg->flash_faults = LED_FAULT_SHORT_CIRCUIT | LED_FAULT_TIMEOUT |
                            LED_FAULT_INPUT_VOLTAGE | LED_FAULT_UNDER_VOLTAGE;
}
#else
static const struct v4l2_flash_ops v4l2_flash_ops;
static void mt6370_init_v4l2_flash_config(struct mt6370_led *led, struct v4l2_flash_config *cfg)
{
}
#endif

static void mt6370_v4l2_flash_release(void *v4l2_flash)
{
        v4l2_flash_release(v4l2_flash);
}

static int mt6370_led_register(struct device *parent, struct mt6370_led *led,
                               struct fwnode_handle *fwnode)
{
        struct led_init_data init_data = { .fwnode = fwnode };
        struct v4l2_flash_config v4l2_config = {};
        int ret;

        ret = devm_led_classdev_flash_register_ext(parent, &led->flash, &init_data);
        if (ret)
                return dev_err_probe(parent, ret, "Couldn't register flash %d\n", led->led_no);

        mt6370_init_v4l2_flash_config(led, &v4l2_config);
        led->v4l2_flash = v4l2_flash_init(parent, fwnode, &led->flash, &v4l2_flash_ops,
                                          &v4l2_config);
        if (IS_ERR(led->v4l2_flash))
                return dev_err_probe(parent, PTR_ERR(led->v4l2_flash),
                                     "Failed to register %d v4l2 sd\n", led->led_no);

        return devm_add_action_or_reset(parent, mt6370_v4l2_flash_release, led->v4l2_flash);
}

static u32 mt6370_clamp(u32 val, u32 min, u32 max, u32 step)
{
        u32 retval;

        retval = clamp_val(val, min, max);
        if (step > 1)
                retval = rounddown(retval - min, step) + min;

        return retval;
}

static int mt6370_init_flash_properties(struct device *dev, struct mt6370_led *led,
                                        struct fwnode_handle *fwnode)
{
        struct led_classdev_flash *flash = &led->flash;
        struct led_classdev *lcdev = &flash->led_cdev;
        struct mt6370_priv *priv = led->priv;
        struct led_flash_setting *s;
        u32 sources[MT6370_MAX_LEDS];
        u32 max_ua, val;
        int i, ret, num;

        num = fwnode_property_count_u32(fwnode, "led-sources");
        if (num < 1)
                return dev_err_probe(dev, -EINVAL,
                                     "Not specified or wrong number of led-sources\n");

        ret = fwnode_property_read_u32_array(fwnode, "led-sources", sources, num);
        if (ret)
                return ret;

        for (i = 0; i < num; i++) {
                if (sources[i] >= MT6370_MAX_LEDS)
                        return -EINVAL;
                if (priv->leds_active & BIT(sources[i]))
                        return -EINVAL;
                priv->leds_active |= BIT(sources[i]);
        }

        /* If both channels are specified in 'led-sources', joint flash output mode is used */
        led->led_no = num == 2 ? MT6370_LED_JOINT : sources[0];

        max_ua = num == 2 ? MT6370_ITORCH_DOUBLE_MAX_uA : MT6370_ITORCH_MAX_uA;
        val = MT6370_ITORCH_MIN_uA;
        ret = fwnode_property_read_u32(fwnode, "led-max-microamp", &val);
        if (!ret)
                val = mt6370_clamp(val, MT6370_ITORCH_MIN_uA, max_ua, MT6370_ITORCH_STEP_uA);

        lcdev->max_brightness = (val - MT6370_ITORCH_MIN_uA) / MT6370_ITORCH_STEP_uA + 1;
        lcdev->brightness_set_blocking = mt6370_torch_brightness_set;
        lcdev->flags |= LED_DEV_CAP_FLASH;

        max_ua = num == 2 ? MT6370_ISTRB_DOUBLE_MAX_uA : MT6370_ISTRB_MAX_uA;
        val = MT6370_ISTRB_MIN_uA;
        ret = fwnode_property_read_u32(fwnode, "flash-max-microamp", &val);
        if (!ret)
                val = mt6370_clamp(val, MT6370_ISTRB_MIN_uA, max_ua, MT6370_ISTRB_STEP_uA);

        s = &flash->brightness;
        s->min = MT6370_ISTRB_MIN_uA;
        s->step = MT6370_ISTRB_STEP_uA;
        s->val = s->max = val;

        /* Always configure to the minimum level when off to prevent flash current spikes. */
        ret = _mt6370_flash_brightness_set(flash, s->min);
        if (ret)
                return ret;

        val = MT6370_STRBTO_MIN_US;
        ret = fwnode_property_read_u32(fwnode, "flash-max-timeout-us", &val);
        if (!ret)
                val = mt6370_clamp(val, MT6370_STRBTO_MIN_US, MT6370_STRBTO_MAX_US,
                                   MT6370_STRBTO_STEP_US);

        s = &flash->timeout;
        s->min = MT6370_STRBTO_MIN_US;
        s->step = MT6370_STRBTO_STEP_US;
        s->val = s->max = val;

        flash->ops = &mt6370_flash_ops;

        return 0;
}

static int mt6370_led_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct mt6370_priv *priv;
        size_t count;
        int i = 0, ret;

        count = device_get_child_node_count(dev);
        if (!count || count > MT6370_MAX_LEDS)
                return dev_err_probe(dev, -EINVAL,
                       "No child node or node count over max led number %zu\n", count);

        priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->leds_count = count;
        mutex_init(&priv->lock);

        priv->regmap = dev_get_regmap(dev->parent, NULL);
        if (!priv->regmap)
                return dev_err_probe(dev, -ENODEV, "Failed to get parent regmap\n");

        device_for_each_child_node_scoped(dev, child) {
                struct mt6370_led *led = priv->leds + i;

                led->priv = priv;

                ret = mt6370_init_flash_properties(dev, led, child);
                if (ret)
                        return ret;

                ret = mt6370_led_register(dev, led, child);
                if (ret)
                        return ret;

                i++;
        }

        return 0;
}

static const struct of_device_id mt6370_led_of_id[] = {
        { .compatible = "mediatek,mt6370-flashlight" },
        {}
};
MODULE_DEVICE_TABLE(of, mt6370_led_of_id);

static struct platform_driver mt6370_led_driver = {
        .driver = {
                .name = "mt6370-flashlight",
                .of_match_table = mt6370_led_of_id,
        },
        .probe = mt6370_led_probe,
};
module_platform_driver(mt6370_led_driver);

MODULE_AUTHOR("Alice Chen <alice_chen@richtek.com>");
MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
MODULE_DESCRIPTION("MT6370 FLASH LED Driver");
MODULE_LICENSE("GPL");