/*
 * LED driver for Mediatek MT6323 PMIC
 *
 * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/mfd/mt6323/registers.h>
#include <linux/mfd/mt6397/core.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

/*
 * Register field for MT6323_TOP_CKPDN0 to enable
 * 32K clock common for LED device.
 */
#define MT6323_RG_DRV_32K_CK_PDN	BIT(11)
#define MT6323_RG_DRV_32K_CK_PDN_MASK	BIT(11)

/*
 * Register field for MT6323_TOP_CKPDN2 to enable
 * individual clock for LED device.
 */
#define MT6323_RG_ISINK_CK_PDN(i)	BIT(i)
#define MT6323_RG_ISINK_CK_PDN_MASK(i)	BIT(i)

/*
 * Register field for MT6323_TOP_CKCON1 to select
 * clock source.
 */
#define MT6323_RG_ISINK_CK_SEL_MASK(i)	(BIT(10) << (i))

/*
 * Register for MT6323_ISINK_CON0 to setup the
 * duty cycle of the blink.
 */
#define MT6323_ISINK_CON0(i)		(MT6323_ISINK0_CON0 + 0x8 * (i))
#define MT6323_ISINK_DIM_DUTY_MASK	(0x1f << 8)
#define MT6323_ISINK_DIM_DUTY(i)	(((i) << 8) & \
					MT6323_ISINK_DIM_DUTY_MASK)

/* Register to setup the period of the blink. */
#define MT6323_ISINK_CON1(i)		(MT6323_ISINK0_CON1 + 0x8 * (i))
#define MT6323_ISINK_DIM_FSEL_MASK	(0xffff)
#define MT6323_ISINK_DIM_FSEL(i)	((i) & MT6323_ISINK_DIM_FSEL_MASK)

/* Register to control the brightness. */
#define MT6323_ISINK_CON2(i)		(MT6323_ISINK0_CON2 + 0x8 * (i))
#define MT6323_ISINK_CH_STEP_SHIFT	12
#define MT6323_ISINK_CH_STEP_MASK	(0x7 << 12)
#define MT6323_ISINK_CH_STEP(i)		(((i) << 12) & \
					MT6323_ISINK_CH_STEP_MASK)
#define MT6323_ISINK_SFSTR0_TC_MASK	(0x3 << 1)
#define MT6323_ISINK_SFSTR0_TC(i)	(((i) << 1) & \
					MT6323_ISINK_SFSTR0_TC_MASK)
#define MT6323_ISINK_SFSTR0_EN_MASK	BIT(0)
#define MT6323_ISINK_SFSTR0_EN		BIT(0)

/* Register to LED channel enablement. */
#define MT6323_ISINK_CH_EN_MASK(i)	BIT(i)
#define MT6323_ISINK_CH_EN(i)		BIT(i)

#define MT6323_MAX_PERIOD		10000
#define MT6323_MAX_LEDS			4
#define MT6323_MAX_BRIGHTNESS		6
#define MT6323_UNIT_DUTY		3125
#define MT6323_CAL_HW_DUTY(o, p)	DIV_ROUND_CLOSEST((o) * 100000ul,\
					(p) * MT6323_UNIT_DUTY)

struct mt6323_leds;

/**
 * struct mt6323_led - state container for the LED device
 * @id:			the identifier in MT6323 LED device
 * @parent:		the pointer to MT6323 LED controller
 * @cdev:		LED class device for this LED device
 * @current_brightness: current state of the LED device
 */
struct mt6323_led {
	int			id;
	struct mt6323_leds	*parent;
	struct led_classdev	cdev;
	enum led_brightness	current_brightness;
};

/**
 * struct mt6323_leds -	state container for holding LED controller
 *			of the driver
 * @dev:		the device pointer
 * @hw:			the underlying hardware providing shared
 *			bus for the register operations
 * @lock:		the lock among process context
 * @led:		the array that contains the state of individual
 *			LED device
 */
struct mt6323_leds {
	struct device		*dev;
	struct mt6397_chip	*hw;
	/* protect among process context */
	struct mutex		lock;
	struct mt6323_led	*led[MT6323_MAX_LEDS];
};

static int mt6323_led_hw_brightness(struct led_classdev *cdev,
				    enum led_brightness brightness)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	struct mt6323_leds *leds = led->parent;
	struct regmap *regmap = leds->hw->regmap;
	u32 con2_mask = 0, con2_val = 0;
	int ret;

	/*
	 * Setup current output for the corresponding
	 * brightness level.
	 */
	con2_mask |= MT6323_ISINK_CH_STEP_MASK |
		     MT6323_ISINK_SFSTR0_TC_MASK |
		     MT6323_ISINK_SFSTR0_EN_MASK;
	con2_val |=  MT6323_ISINK_CH_STEP(brightness - 1) |
		     MT6323_ISINK_SFSTR0_TC(2) |
		     MT6323_ISINK_SFSTR0_EN;

	ret = regmap_update_bits(regmap, MT6323_ISINK_CON2(led->id),
				 con2_mask, con2_val);
	return ret;
}

static int mt6323_led_hw_off(struct led_classdev *cdev)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	struct mt6323_leds *leds = led->parent;
	struct regmap *regmap = leds->hw->regmap;
	unsigned int status;
	int ret;

	status = MT6323_ISINK_CH_EN(led->id);
	ret = regmap_update_bits(regmap, MT6323_ISINK_EN_CTRL,
				 MT6323_ISINK_CH_EN_MASK(led->id), ~status);
	if (ret < 0)
		return ret;

	usleep_range(100, 300);
	ret = regmap_update_bits(regmap, MT6323_TOP_CKPDN2,
				 MT6323_RG_ISINK_CK_PDN_MASK(led->id),
				 MT6323_RG_ISINK_CK_PDN(led->id));
	if (ret < 0)
		return ret;

	return 0;
}

static enum led_brightness
mt6323_get_led_hw_brightness(struct led_classdev *cdev)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	struct mt6323_leds *leds = led->parent;
	struct regmap *regmap = leds->hw->regmap;
	unsigned int status;
	int ret;

	ret = regmap_read(regmap, MT6323_TOP_CKPDN2, &status);
	if (ret < 0)
		return ret;

	if (status & MT6323_RG_ISINK_CK_PDN_MASK(led->id))
		return 0;

	ret = regmap_read(regmap, MT6323_ISINK_EN_CTRL, &status);
	if (ret < 0)
		return ret;

	if (!(status & MT6323_ISINK_CH_EN(led->id)))
		return 0;

	ret = regmap_read(regmap, MT6323_ISINK_CON2(led->id), &status);
	if (ret < 0)
		return ret;

	return  ((status & MT6323_ISINK_CH_STEP_MASK)
		  >> MT6323_ISINK_CH_STEP_SHIFT) + 1;
}

static int mt6323_led_hw_on(struct led_classdev *cdev,
			    enum led_brightness brightness)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	struct mt6323_leds *leds = led->parent;
	struct regmap *regmap = leds->hw->regmap;
	unsigned int status;
	int ret;

	/*
	 * Setup required clock source, enable the corresponding
	 * clock and channel and let work with continuous blink as
	 * the default.
	 */
	ret = regmap_update_bits(regmap, MT6323_TOP_CKCON1,
				 MT6323_RG_ISINK_CK_SEL_MASK(led->id), 0);
	if (ret < 0)
		return ret;

	status = MT6323_RG_ISINK_CK_PDN(led->id);
	ret = regmap_update_bits(regmap, MT6323_TOP_CKPDN2,
				 MT6323_RG_ISINK_CK_PDN_MASK(led->id),
				 ~status);
	if (ret < 0)
		return ret;

	usleep_range(100, 300);

	ret = regmap_update_bits(regmap, MT6323_ISINK_EN_CTRL,
				 MT6323_ISINK_CH_EN_MASK(led->id),
				 MT6323_ISINK_CH_EN(led->id));
	if (ret < 0)
		return ret;

	ret = mt6323_led_hw_brightness(cdev, brightness);
	if (ret < 0)
		return ret;

	ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
				 MT6323_ISINK_DIM_DUTY_MASK,
				 MT6323_ISINK_DIM_DUTY(31));
	if (ret < 0)
		return ret;

	ret = regmap_update_bits(regmap, MT6323_ISINK_CON1(led->id),
				 MT6323_ISINK_DIM_FSEL_MASK,
				 MT6323_ISINK_DIM_FSEL(1000));
	if (ret < 0)
		return ret;

	return 0;
}

static int mt6323_led_set_blink(struct led_classdev *cdev,
				unsigned long *delay_on,
				unsigned long *delay_off)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	struct mt6323_leds *leds = led->parent;
	struct regmap *regmap = leds->hw->regmap;
	unsigned long period;
	u8 duty_hw;
	int ret;

	/*
	 * Units are in ms, if over the hardware able
	 * to support, fallback into software blink
	 */
	period = *delay_on + *delay_off;

	if (period > MT6323_MAX_PERIOD)
		return -EINVAL;

	/*
	 * LED subsystem requires a default user
	 * friendly blink pattern for the LED so using
	 * 1Hz duty cycle 50% here if without specific
	 * value delay_on and delay off being assigned.
	 */
	if (!*delay_on && !*delay_off) {
		*delay_on = 500;
		*delay_off = 500;
	}

	/*
	 * Calculate duty_hw based on the percentage of period during
	 * which the led is ON.
	 */
	duty_hw = MT6323_CAL_HW_DUTY(*delay_on, period);

	/* hardware doesn't support zero duty cycle. */
	if (!duty_hw)
		return -EINVAL;

	mutex_lock(&leds->lock);
	/*
	 * Set max_brightness as the software blink behavior
	 * when no blink brightness.
	 */
	if (!led->current_brightness) {
		ret = mt6323_led_hw_on(cdev, cdev->max_brightness);
		if (ret < 0)
			goto out;
		led->current_brightness = cdev->max_brightness;
	}

	ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
				 MT6323_ISINK_DIM_DUTY_MASK,
				 MT6323_ISINK_DIM_DUTY(duty_hw - 1));
	if (ret < 0)
		goto out;

	ret = regmap_update_bits(regmap, MT6323_ISINK_CON1(led->id),
				 MT6323_ISINK_DIM_FSEL_MASK,
				 MT6323_ISINK_DIM_FSEL(period - 1));
out:
	mutex_unlock(&leds->lock);

	return ret;
}

static int mt6323_led_set_brightness(struct led_classdev *cdev,
				     enum led_brightness brightness)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	struct mt6323_leds *leds = led->parent;
	int ret;

	mutex_lock(&leds->lock);

	if (!led->current_brightness && brightness) {
		ret = mt6323_led_hw_on(cdev, brightness);
		if (ret < 0)
			goto out;
	} else if (brightness) {
		ret = mt6323_led_hw_brightness(cdev, brightness);
		if (ret < 0)
			goto out;
	} else {
		ret = mt6323_led_hw_off(cdev);
		if (ret < 0)
			goto out;
	}

	led->current_brightness = brightness;
out:
	mutex_unlock(&leds->lock);

	return ret;
}

static int mt6323_led_set_dt_default(struct led_classdev *cdev,
				     struct device_node *np)
{
	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
	const char *state;
	int ret = 0;

	led->cdev.name = of_get_property(np, "label", NULL) ? : np->name;
	led->cdev.default_trigger = of_get_property(np,
						    "linux,default-trigger",
						    NULL);

	state = of_get_property(np, "default-state", NULL);
	if (state) {
		if (!strcmp(state, "keep")) {
			ret = mt6323_get_led_hw_brightness(cdev);
			if (ret < 0)
				return ret;
			led->current_brightness = ret;
			ret = 0;
		} else if (!strcmp(state, "on")) {
			ret =
			mt6323_led_set_brightness(cdev, cdev->max_brightness);
		} else  {
			ret = mt6323_led_set_brightness(cdev, LED_OFF);
		}
	}

	return ret;
}

static int mt6323_led_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = pdev->dev.of_node;
	struct device_node *child;
	struct mt6397_chip *hw = dev_get_drvdata(pdev->dev.parent);
	struct mt6323_leds *leds;
	struct mt6323_led *led;
	int ret;
	unsigned int status;
	u32 reg;

	leds = devm_kzalloc(dev, sizeof(*leds), GFP_KERNEL);
	if (!leds)
		return -ENOMEM;

	platform_set_drvdata(pdev, leds);
	leds->dev = dev;

	/*
	 * leds->hw points to the underlying bus for the register
	 * controlled.
	 */
	leds->hw = hw;
	mutex_init(&leds->lock);

	status = MT6323_RG_DRV_32K_CK_PDN;
	ret = regmap_update_bits(leds->hw->regmap, MT6323_TOP_CKPDN0,
				 MT6323_RG_DRV_32K_CK_PDN_MASK, ~status);
	if (ret < 0) {
		dev_err(leds->dev,
			"Failed to update MT6323_TOP_CKPDN0 Register\n");
		return ret;
	}

	for_each_available_child_of_node(np, child) {
		ret = of_property_read_u32(child, "reg", &reg);
		if (ret) {
			dev_err(dev, "Failed to read led 'reg' property\n");
			goto put_child_node;
		}

		if (reg >= MT6323_MAX_LEDS || leds->led[reg]) {
			dev_err(dev, "Invalid led reg %u\n", reg);
			ret = -EINVAL;
			goto put_child_node;
		}

		led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
		if (!led) {
			ret = -ENOMEM;
			goto put_child_node;
		}

		leds->led[reg] = led;
		leds->led[reg]->id = reg;
		leds->led[reg]->cdev.max_brightness = MT6323_MAX_BRIGHTNESS;
		leds->led[reg]->cdev.brightness_set_blocking =
					mt6323_led_set_brightness;
		leds->led[reg]->cdev.blink_set = mt6323_led_set_blink;
		leds->led[reg]->cdev.brightness_get =
					mt6323_get_led_hw_brightness;
		leds->led[reg]->parent = leds;

		ret = mt6323_led_set_dt_default(&leds->led[reg]->cdev, child);
		if (ret < 0) {
			dev_err(leds->dev,
				"Failed to LED set default from devicetree\n");
			goto put_child_node;
		}

		ret = devm_led_classdev_register(dev, &leds->led[reg]->cdev);
		if (ret) {
			dev_err(&pdev->dev, "Failed to register LED: %d\n",
				ret);
			goto put_child_node;
		}
		leds->led[reg]->cdev.dev->of_node = child;
	}

	return 0;

put_child_node:
	of_node_put(child);
	return ret;
}

static int mt6323_led_remove(struct platform_device *pdev)
{
	struct mt6323_leds *leds = platform_get_drvdata(pdev);
	int i;

	/* Turn the LEDs off on driver removal. */
	for (i = 0 ; leds->led[i] ; i++)
		mt6323_led_hw_off(&leds->led[i]->cdev);

	regmap_update_bits(leds->hw->regmap, MT6323_TOP_CKPDN0,
			   MT6323_RG_DRV_32K_CK_PDN_MASK,
			   MT6323_RG_DRV_32K_CK_PDN);

	mutex_destroy(&leds->lock);

	return 0;
}

static const struct of_device_id mt6323_led_dt_match[] = {
	{ .compatible = "mediatek,mt6323-led" },
	{},
};
MODULE_DEVICE_TABLE(of, mt6323_led_dt_match);

static struct platform_driver mt6323_led_driver = {
	.probe		= mt6323_led_probe,
	.remove		= mt6323_led_remove,
	.driver		= {
		.name	= "mt6323-led",
		.of_match_table = mt6323_led_dt_match,
	},
};

module_platform_driver(mt6323_led_driver);

MODULE_DESCRIPTION("LED driver for Mediatek MT6323 PMIC");
MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
MODULE_LICENSE("GPL");