drivers/leds/flash/leds-mt6370-flash.c

// 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[];
};

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

		led->priv = priv;

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

		ret = mt6370_led_register(dev, led, child);
		if (ret) {
			fwnode_handle_put(child);
			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");