drivers/leds/leds-ktd2692.c - linux - Git at Google

 /*
  * LED driver : leds-ktd2692.c
  *
  * Copyright (C) 2015 Samsung Electronics
  * Ingi Kim <ingi2.kim@samsung.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/gpio/consumer.h>
 #include <linux/led-class-flash.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>

 /* Value related the movie mode */
 #define KTD2692_MOVIE_MODE_CURRENT_LEVELS	16
 #define KTD2692_MM_TO_FL_RATIO(x)		((x) / 3)
 #define KTD2962_MM_MIN_CURR_THRESHOLD_SCALE	8

 /* Value related the flash mode */
 #define KTD2692_FLASH_MODE_TIMEOUT_LEVELS	8
 #define KTD2692_FLASH_MODE_TIMEOUT_DISABLE	0
 #define KTD2692_FLASH_MODE_CURR_PERCENT(x)	(((x) * 16) / 100)

 /* Macro for getting offset of flash timeout */
 #define GET_TIMEOUT_OFFSET(timeout, step)	((timeout) / (step))

 /* Base register address */
 #define KTD2692_REG_LVP_BASE			0x00
 #define KTD2692_REG_FLASH_TIMEOUT_BASE		0x20
 #define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE	0x40
 #define KTD2692_REG_MOVIE_CURRENT_BASE		0x60
 #define KTD2692_REG_FLASH_CURRENT_BASE		0x80
 #define KTD2692_REG_MODE_BASE			0xA0

 /* Set bit coding time for expresswire interface */
 #define KTD2692_TIME_RESET_US			700
 #define KTD2692_TIME_DATA_START_TIME_US		10
 #define KTD2692_TIME_HIGH_END_OF_DATA_US	350
 #define KTD2692_TIME_LOW_END_OF_DATA_US		10
 #define KTD2692_TIME_SHORT_BITSET_US		4
 #define KTD2692_TIME_LONG_BITSET_US		12

 /* KTD2692 default length of name */
 #define KTD2692_NAME_LENGTH			20

 enum ktd2692_bitset {
 	KTD2692_LOW = 0,
 	KTD2692_HIGH,
 };

 /* Movie / Flash Mode Control */
 enum ktd2692_led_mode {
 	KTD2692_MODE_DISABLE = 0,	/* default */
 	KTD2692_MODE_MOVIE,
 	KTD2692_MODE_FLASH,
 };

 struct ktd2692_led_config_data {
 	/* maximum LED current in movie mode */
 	u32 movie_max_microamp;
 	/* maximum LED current in flash mode */
 	u32 flash_max_microamp;
 	/* maximum flash timeout */
 	u32 flash_max_timeout;
 	/* max LED brightness level */
 	enum led_brightness max_brightness;
 };

 struct ktd2692_context {
 	/* Related LED Flash class device */
 	struct led_classdev_flash fled_cdev;

 	/* secures access to the device */
 	struct mutex lock;
 	struct regulator *regulator;

 	struct gpio_desc *aux_gpio;
 	struct gpio_desc *ctrl_gpio;

 	enum ktd2692_led_mode mode;
 	enum led_brightness torch_brightness;
 };

 static struct ktd2692_context *fled_cdev_to_led(
 				struct led_classdev_flash *fled_cdev)
 {
 	return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
 }

 static void ktd2692_expresswire_start(struct ktd2692_context *led)
 {
 	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 	udelay(KTD2692_TIME_DATA_START_TIME_US);
 }

 static void ktd2692_expresswire_reset(struct ktd2692_context *led)
 {
 	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 	udelay(KTD2692_TIME_RESET_US);
 }

 static void ktd2692_expresswire_end(struct ktd2692_context *led)
 {
 	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 	udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
 	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 	udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
 }

 static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
 {
 	/*
 	 * The Low Bit(0) and High Bit(1) is based on a time detection
 	 * algorithm between time low and time high
 	 * Time_(L_LB) : Low time of the Low Bit(0)
 	 * Time_(H_LB) : High time of the LOW Bit(0)
 	 * Time_(L_HB) : Low time of the High Bit(1)
 	 * Time_(H_HB) : High time of the High Bit(1)
 	 *
 	 * It can be simplified to:
 	 * Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
 	 * High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
 	 * HIGH  ___           ____    _..     _________    ___
 	 *          |_________|    |_..  |____|         |__|
 	 * LOW        <L_LB>  <H_LB>     <L_HB>  <H_HB>
 	 *          [  Low Bit (0) ]     [  High Bit(1) ]
 	 */
 	if (bit) {
 		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 		udelay(KTD2692_TIME_SHORT_BITSET_US);
 		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 		udelay(KTD2692_TIME_LONG_BITSET_US);
 	} else {
 		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 		udelay(KTD2692_TIME_LONG_BITSET_US);
 		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 		udelay(KTD2692_TIME_SHORT_BITSET_US);
 	}
 }

 static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
 {
 	int i;

 	ktd2692_expresswire_start(led);
 	for (i = 7; i >= 0; i--)
 		ktd2692_expresswire_set_bit(led, value & BIT(i));
 	ktd2692_expresswire_end(led);
 }

 static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
 				       enum led_brightness brightness)
 {
 	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);

 	mutex_lock(&led->lock);

 	if (brightness == LED_OFF) {
 		led->mode = KTD2692_MODE_DISABLE;
 		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
 	} else {
 		ktd2692_expresswire_write(led, brightness |
 					KTD2692_REG_MOVIE_CURRENT_BASE);
 		led->mode = KTD2692_MODE_MOVIE;
 	}

 	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
 	mutex_unlock(&led->lock);

 	return 0;
 }

 static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 					bool state)
 {
 	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
 	struct led_flash_setting *timeout = &fled_cdev->timeout;
 	u32 flash_tm_reg;

 	mutex_lock(&led->lock);

 	if (state) {
 		flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
 		ktd2692_expresswire_write(led, flash_tm_reg
 				| KTD2692_REG_FLASH_TIMEOUT_BASE);

 		led->mode = KTD2692_MODE_FLASH;
 		gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
 	} else {
 		led->mode = KTD2692_MODE_DISABLE;
 		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
 	}

 	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);

 	fled_cdev->led_cdev.brightness = LED_OFF;
 	led->mode = KTD2692_MODE_DISABLE;

 	mutex_unlock(&led->lock);

 	return 0;
 }

 static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 					 u32 timeout)
 {
 	return 0;
 }

 static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
 {
 	u32 offset, step;
 	u32 movie_current_microamp;

 	offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
 	step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
 		/ KTD2692_MOVIE_MODE_CURRENT_LEVELS;

 	do {
 		movie_current_microamp = step * offset;
 		offset--;
 	} while ((movie_current_microamp > cfg->movie_max_microamp) &&
 		(offset > 0));

 	cfg->max_brightness = offset;
 }

 static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
 				       struct ktd2692_led_config_data *cfg)
 {
 	struct led_flash_setting *setting;

 	setting = &fled_cdev->timeout;
 	setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
 	setting->max = cfg->flash_max_timeout;
 	setting->step = cfg->flash_max_timeout
 			/ (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
 	setting->val = cfg->flash_max_timeout;
 }

 static void ktd2692_setup(struct ktd2692_context *led)
 {
 	led->mode = KTD2692_MODE_DISABLE;
 	ktd2692_expresswire_reset(led);
 	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);

 	ktd2692_expresswire_write(led, (KTD2962_MM_MIN_CURR_THRESHOLD_SCALE - 1)
 				 | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
 	ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
 				 | KTD2692_REG_FLASH_CURRENT_BASE);
 }

 static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
 			    struct ktd2692_led_config_data *cfg)
 {
 	struct device_node *np = dev->of_node;
 	struct device_node *child_node;
 	int ret;

 	if (!dev->of_node)
 		return -ENXIO;

 	led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
 	ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
 	if (ret) {
 		dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
 		return ret;
 	}

 	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
 	ret = PTR_ERR_OR_ZERO(led->aux_gpio);
 	if (ret) {
 		dev_err(dev, "cannot get aux-gpios %d\n", ret);
 		return ret;
 	}

 	led->regulator = devm_regulator_get(dev, "vin");
 	if (IS_ERR(led->regulator))
 		led->regulator = NULL;

 	if (led->regulator) {
 		ret = regulator_enable(led->regulator);
 		if (ret)
 			dev_err(dev, "Failed to enable supply: %d\n", ret);
 	}

 	child_node = of_get_next_available_child(np, NULL);
 	if (!child_node) {
 		dev_err(dev, "No DT child node found for connected LED.\n");
 		return -EINVAL;
 	}

 	led->fled_cdev.led_cdev.name =
 		of_get_property(child_node, "label", NULL) ? : child_node->name;

 	ret = of_property_read_u32(child_node, "led-max-microamp",
 				   &cfg->movie_max_microamp);
 	if (ret) {
 		dev_err(dev, "failed to parse led-max-microamp\n");
 		goto err_parse_dt;
 	}

 	ret = of_property_read_u32(child_node, "flash-max-microamp",
 				   &cfg->flash_max_microamp);
 	if (ret) {
 		dev_err(dev, "failed to parse flash-max-microamp\n");
 		goto err_parse_dt;
 	}

 	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
 				   &cfg->flash_max_timeout);
 	if (ret) {
 		dev_err(dev, "failed to parse flash-max-timeout-us\n");
 		goto err_parse_dt;
 	}

 err_parse_dt:
 	of_node_put(child_node);
 	return ret;
 }

 static const struct led_flash_ops flash_ops = {
 	.strobe_set = ktd2692_led_flash_strobe_set,
 	.timeout_set = ktd2692_led_flash_timeout_set,
 };

 static int ktd2692_probe(struct platform_device *pdev)
 {
 	struct ktd2692_context *led;
 	struct led_classdev *led_cdev;
 	struct led_classdev_flash *fled_cdev;
 	struct ktd2692_led_config_data led_cfg;
 	int ret;

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

 	fled_cdev = &led->fled_cdev;
 	led_cdev = &fled_cdev->led_cdev;

 	ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
 	if (ret)
 		return ret;

 	ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
 	ktd2692_init_movie_current_max(&led_cfg);

 	fled_cdev->ops = &flash_ops;

 	led_cdev->max_brightness = led_cfg.max_brightness;
 	led_cdev->brightness_set_blocking = ktd2692_led_brightness_set;
 	led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;

 	mutex_init(&led->lock);

 	platform_set_drvdata(pdev, led);

 	ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
 	if (ret) {
 		dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
 		mutex_destroy(&led->lock);
 		return ret;
 	}

 	ktd2692_setup(led);

 	return 0;
 }

 static int ktd2692_remove(struct platform_device *pdev)
 {
 	struct ktd2692_context *led = platform_get_drvdata(pdev);
 	int ret;

 	led_classdev_flash_unregister(&led->fled_cdev);

 	if (led->regulator) {
 		ret = regulator_disable(led->regulator);
 		if (ret)
 			dev_err(&pdev->dev,
 				"Failed to disable supply: %d\n", ret);
 	}

 	mutex_destroy(&led->lock);

 	return 0;
 }

 static const struct of_device_id ktd2692_match[] = {
 	{ .compatible = "kinetic,ktd2692", },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, ktd2692_match);

 static struct platform_driver ktd2692_driver = {
 	.driver = {
 		.name  = "ktd2692",
 		.of_match_table = ktd2692_match,
 	},
 	.probe  = ktd2692_probe,
 	.remove = ktd2692_remove,
 };

 module_platform_driver(ktd2692_driver);

 MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
 MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
 MODULE_LICENSE("GPL v2");
	/*
	* LED driver : leds-ktd2692.c
	*
	* Copyright (C) 2015 Samsung Electronics
	* Ingi Kim <ingi2.kim@samsung.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/gpio/consumer.h>
	#include <linux/led-class-flash.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regulator/consumer.h>

	/* Value related the movie mode */
	#define KTD2692_MOVIE_MODE_CURRENT_LEVELS 16
	#define KTD2692_MM_TO_FL_RATIO(x) ((x) / 3)
	#define KTD2962_MM_MIN_CURR_THRESHOLD_SCALE 8

	/* Value related the flash mode */
	#define KTD2692_FLASH_MODE_TIMEOUT_LEVELS 8
	#define KTD2692_FLASH_MODE_TIMEOUT_DISABLE 0
	#define KTD2692_FLASH_MODE_CURR_PERCENT(x) (((x) * 16) / 100)

	/* Macro for getting offset of flash timeout */
	#define GET_TIMEOUT_OFFSET(timeout, step) ((timeout) / (step))

	/* Base register address */
	#define KTD2692_REG_LVP_BASE 0x00
	#define KTD2692_REG_FLASH_TIMEOUT_BASE 0x20
	#define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE 0x40
	#define KTD2692_REG_MOVIE_CURRENT_BASE 0x60
	#define KTD2692_REG_FLASH_CURRENT_BASE 0x80
	#define KTD2692_REG_MODE_BASE 0xA0

	/* Set bit coding time for expresswire interface */
	#define KTD2692_TIME_RESET_US 700
	#define KTD2692_TIME_DATA_START_TIME_US 10
	#define KTD2692_TIME_HIGH_END_OF_DATA_US 350
	#define KTD2692_TIME_LOW_END_OF_DATA_US 10
	#define KTD2692_TIME_SHORT_BITSET_US 4
	#define KTD2692_TIME_LONG_BITSET_US 12

	/* KTD2692 default length of name */
	#define KTD2692_NAME_LENGTH 20

	enum ktd2692_bitset {
	KTD2692_LOW = 0,
	KTD2692_HIGH,
	};

	/* Movie / Flash Mode Control */
	enum ktd2692_led_mode {
	KTD2692_MODE_DISABLE = 0, /* default */
	KTD2692_MODE_MOVIE,
	KTD2692_MODE_FLASH,
	};

	struct ktd2692_led_config_data {
	/* maximum LED current in movie mode */
	u32 movie_max_microamp;
	/* maximum LED current in flash mode */
	u32 flash_max_microamp;
	/* maximum flash timeout */
	u32 flash_max_timeout;
	/* max LED brightness level */
	enum led_brightness max_brightness;
	};

	struct ktd2692_context {
	/* Related LED Flash class device */
	struct led_classdev_flash fled_cdev;

	/* secures access to the device */
	struct mutex lock;
	struct regulator *regulator;

	struct gpio_desc *aux_gpio;
	struct gpio_desc *ctrl_gpio;

	enum ktd2692_led_mode mode;
	enum led_brightness torch_brightness;
	};

	static struct ktd2692_context *fled_cdev_to_led(
	struct led_classdev_flash *fled_cdev)
	{
	return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
	}

	static void ktd2692_expresswire_start(struct ktd2692_context *led)
	{
	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
	udelay(KTD2692_TIME_DATA_START_TIME_US);
	}

	static void ktd2692_expresswire_reset(struct ktd2692_context *led)
	{
	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
	udelay(KTD2692_TIME_RESET_US);
	}

	static void ktd2692_expresswire_end(struct ktd2692_context *led)
	{
	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
	udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
	udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
	}

	static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
	{
	/*
	* The Low Bit(0) and High Bit(1) is based on a time detection
	* algorithm between time low and time high
	* Time_(L_LB) : Low time of the Low Bit(0)
	* Time_(H_LB) : High time of the LOW Bit(0)
	* Time_(L_HB) : Low time of the High Bit(1)
	* Time_(H_HB) : High time of the High Bit(1)
	*
	* It can be simplified to:
	* Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
	* High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
	* HIGH ___ ____ _.. _________ ___
	* \|_________\| \|_.. \|____\| \|__\|
	* LOW <L_LB> <H_LB> <L_HB> <H_HB>
	* [ Low Bit (0) ] [ High Bit(1) ]
	*/
	if (bit) {
	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
	udelay(KTD2692_TIME_SHORT_BITSET_US);
	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
	udelay(KTD2692_TIME_LONG_BITSET_US);
	} else {
	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
	udelay(KTD2692_TIME_LONG_BITSET_US);
	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
	udelay(KTD2692_TIME_SHORT_BITSET_US);
	}
	}

	static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
	{
	int i;

	ktd2692_expresswire_start(led);
	for (i = 7; i >= 0; i--)
	ktd2692_expresswire_set_bit(led, value & BIT(i));
	ktd2692_expresswire_end(led);
	}

	static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
	enum led_brightness brightness)
	{
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);

	mutex_lock(&led->lock);

	if (brightness == LED_OFF) {
	led->mode = KTD2692_MODE_DISABLE;
	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
	} else {
	ktd2692_expresswire_write(led, brightness \|
	KTD2692_REG_MOVIE_CURRENT_BASE);
	led->mode = KTD2692_MODE_MOVIE;
	}

	ktd2692_expresswire_write(led, led->mode \| KTD2692_REG_MODE_BASE);
	mutex_unlock(&led->lock);

	return 0;
	}

	static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
	bool state)
	{
	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
	struct led_flash_setting *timeout = &fled_cdev->timeout;
	u32 flash_tm_reg;

	mutex_lock(&led->lock);

	if (state) {
	flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
	ktd2692_expresswire_write(led, flash_tm_reg
	\| KTD2692_REG_FLASH_TIMEOUT_BASE);

	led->mode = KTD2692_MODE_FLASH;
	gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
	} else {
	led->mode = KTD2692_MODE_DISABLE;
	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
	}

	ktd2692_expresswire_write(led, led->mode \| KTD2692_REG_MODE_BASE);

	fled_cdev->led_cdev.brightness = LED_OFF;
	led->mode = KTD2692_MODE_DISABLE;

	mutex_unlock(&led->lock);

	return 0;
	}

	static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
	u32 timeout)
	{
	return 0;
	}

	static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
	{
	u32 offset, step;
	u32 movie_current_microamp;

	offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
	step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
	/ KTD2692_MOVIE_MODE_CURRENT_LEVELS;

	do {
	movie_current_microamp = step * offset;
	offset--;
	} while ((movie_current_microamp > cfg->movie_max_microamp) &&
	(offset > 0));

	cfg->max_brightness = offset;
	}

	static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
	struct ktd2692_led_config_data *cfg)
	{
	struct led_flash_setting *setting;

	setting = &fled_cdev->timeout;
	setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
	setting->max = cfg->flash_max_timeout;
	setting->step = cfg->flash_max_timeout
	/ (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
	setting->val = cfg->flash_max_timeout;
	}

	static void ktd2692_setup(struct ktd2692_context *led)
	{
	led->mode = KTD2692_MODE_DISABLE;
	ktd2692_expresswire_reset(led);
	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);

	ktd2692_expresswire_write(led, (KTD2962_MM_MIN_CURR_THRESHOLD_SCALE - 1)
	\| KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
	ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
	\| KTD2692_REG_FLASH_CURRENT_BASE);
	}

	static int ktd2692_parse_dt(struct ktd2692_context led, struct device dev,
	struct ktd2692_led_config_data *cfg)
	{
	struct device_node *np = dev->of_node;
	struct device_node *child_node;
	int ret;

	if (!dev->of_node)
	return -ENXIO;

	led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
	ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
	if (ret) {
	dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
	return ret;
	}

	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
	ret = PTR_ERR_OR_ZERO(led->aux_gpio);
	if (ret) {
	dev_err(dev, "cannot get aux-gpios %d\n", ret);
	return ret;
	}

	led->regulator = devm_regulator_get(dev, "vin");
	if (IS_ERR(led->regulator))
	led->regulator = NULL;

	if (led->regulator) {
	ret = regulator_enable(led->regulator);
	if (ret)
	dev_err(dev, "Failed to enable supply: %d\n", ret);
	}

	child_node = of_get_next_available_child(np, NULL);
	if (!child_node) {
	dev_err(dev, "No DT child node found for connected LED.\n");
	return -EINVAL;
	}

	led->fled_cdev.led_cdev.name =
	of_get_property(child_node, "label", NULL) ? : child_node->name;

	ret = of_property_read_u32(child_node, "led-max-microamp",
	&cfg->movie_max_microamp);
	if (ret) {
	dev_err(dev, "failed to parse led-max-microamp\n");
	goto err_parse_dt;
	}

	ret = of_property_read_u32(child_node, "flash-max-microamp",
	&cfg->flash_max_microamp);
	if (ret) {
	dev_err(dev, "failed to parse flash-max-microamp\n");
	goto err_parse_dt;
	}

	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
	&cfg->flash_max_timeout);
	if (ret) {
	dev_err(dev, "failed to parse flash-max-timeout-us\n");
	goto err_parse_dt;
	}

	err_parse_dt:
	of_node_put(child_node);
	return ret;
	}

	static const struct led_flash_ops flash_ops = {
	.strobe_set = ktd2692_led_flash_strobe_set,
	.timeout_set = ktd2692_led_flash_timeout_set,
	};

	static int ktd2692_probe(struct platform_device *pdev)
	{
	struct ktd2692_context *led;
	struct led_classdev *led_cdev;
	struct led_classdev_flash *fled_cdev;
	struct ktd2692_led_config_data led_cfg;
	int ret;

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

	fled_cdev = &led->fled_cdev;
	led_cdev = &fled_cdev->led_cdev;

	ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
	if (ret)
	return ret;

	ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
	ktd2692_init_movie_current_max(&led_cfg);

	fled_cdev->ops = &flash_ops;

	led_cdev->max_brightness = led_cfg.max_brightness;
	led_cdev->brightness_set_blocking = ktd2692_led_brightness_set;
	led_cdev->flags \|= LED_CORE_SUSPENDRESUME \| LED_DEV_CAP_FLASH;

	mutex_init(&led->lock);

	platform_set_drvdata(pdev, led);

	ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
	if (ret) {
	dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
	mutex_destroy(&led->lock);
	return ret;
	}

	ktd2692_setup(led);

	return 0;
	}

	static int ktd2692_remove(struct platform_device *pdev)
	{
	struct ktd2692_context *led = platform_get_drvdata(pdev);
	int ret;

	led_classdev_flash_unregister(&led->fled_cdev);

	if (led->regulator) {
	ret = regulator_disable(led->regulator);
	if (ret)
	dev_err(&pdev->dev,
	"Failed to disable supply: %d\n", ret);
	}

	mutex_destroy(&led->lock);

	return 0;
	}

	static const struct of_device_id ktd2692_match[] = {
	{ .compatible = "kinetic,ktd2692", },
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(of, ktd2692_match);

	static struct platform_driver ktd2692_driver = {
	.driver = {
	.name = "ktd2692",
	.of_match_table = ktd2692_match,
	},
	.probe = ktd2692_probe,
	.remove = ktd2692_remove,
	};

	module_platform_driver(ktd2692_driver);

	MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
	MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
	MODULE_LICENSE("GPL v2");