drivers/leds/flash/leds-aat1290.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *	LED Flash class driver for the AAT1290
  *	1.5A Step-Up Current Regulator for Flash LEDs
  *
  *	Copyright (C) 2015, Samsung Electronics Co., Ltd.
  *	Author: Jacek Anaszewski <j.anaszewski@samsung.com>
  */

 #include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/led-class-flash.h>
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <media/v4l2-flash-led-class.h>

 #define AAT1290_MOVIE_MODE_CURRENT_ADDR	17
 #define AAT1290_MAX_MM_CURR_PERCENT_0	16
 #define AAT1290_MAX_MM_CURR_PERCENT_100	1

 #define AAT1290_FLASH_SAFETY_TIMER_ADDR	18

 #define AAT1290_MOVIE_MODE_CONFIG_ADDR	19
 #define AAT1290_MOVIE_MODE_OFF		1
 #define AAT1290_MOVIE_MODE_ON		3

 #define AAT1290_MM_CURRENT_RATIO_ADDR	20
 #define AAT1290_MM_TO_FL_1_92		1

 #define AAT1290_MM_TO_FL_RATIO		1000 / 1920
 #define AAT1290_MAX_MM_CURRENT(fl_max)	(fl_max * AAT1290_MM_TO_FL_RATIO)

 #define AAT1290_LATCH_TIME_MIN_US	500
 #define AAT1290_LATCH_TIME_MAX_US	1000
 #define AAT1290_EN_SET_TICK_TIME_US	1
 #define AAT1290_FLEN_OFF_DELAY_TIME_US	10
 #define AAT1290_FLASH_TM_NUM_LEVELS	16
 #define AAT1290_MM_CURRENT_SCALE_SIZE	15

 #define AAT1290_NAME			"aat1290"


 struct aat1290_led_config_data {
 	/* maximum LED current in movie mode */
 	u32 max_mm_current;
 	/* maximum LED current in flash mode */
 	u32 max_flash_current;
 	/* maximum flash timeout */
 	u32 max_flash_tm;
 	/* external strobe capability */
 	bool has_external_strobe;
 	/* max LED brightness level */
 	enum led_brightness max_brightness;
 };

 struct aat1290_led {
 	/* platform device data */
 	struct platform_device *pdev;
 	/* secures access to the device */
 	struct mutex lock;

 	/* corresponding LED Flash class device */
 	struct led_classdev_flash fled_cdev;
 	/* V4L2 Flash device */
 	struct v4l2_flash *v4l2_flash;

 	/* FLEN pin */
 	struct gpio_desc *gpio_fl_en;
 	/* EN|SET pin  */
 	struct gpio_desc *gpio_en_set;
 	/* movie mode current scale */
 	int *mm_current_scale;
 	/* device mode */
 	bool movie_mode;
 };

 static struct aat1290_led *fled_cdev_to_led(
 				struct led_classdev_flash *fled_cdev)
 {
 	return container_of(fled_cdev, struct aat1290_led, fled_cdev);
 }

 static struct led_classdev_flash *led_cdev_to_fled_cdev(
 				struct led_classdev *led_cdev)
 {
 	return container_of(led_cdev, struct led_classdev_flash, led_cdev);
 }

 static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
 {
 	int i;

 	gpiod_direction_output(led->gpio_fl_en, 0);
 	gpiod_direction_output(led->gpio_en_set, 0);

 	udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);

 	/* write address */
 	for (i = 0; i < addr; ++i) {
 		udelay(AAT1290_EN_SET_TICK_TIME_US);
 		gpiod_direction_output(led->gpio_en_set, 0);
 		udelay(AAT1290_EN_SET_TICK_TIME_US);
 		gpiod_direction_output(led->gpio_en_set, 1);
 	}

 	usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);

 	/* write data */
 	for (i = 0; i < value; ++i) {
 		udelay(AAT1290_EN_SET_TICK_TIME_US);
 		gpiod_direction_output(led->gpio_en_set, 0);
 		udelay(AAT1290_EN_SET_TICK_TIME_US);
 		gpiod_direction_output(led->gpio_en_set, 1);
 	}

 	usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 }

 static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
 					unsigned int micro_sec)
 {
 	struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 	struct led_flash_setting *flash_tm = &fled_cdev->timeout;
 	int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
 				(micro_sec / flash_tm->step) + 1;

 	aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
 							flash_tm_reg);
 }

 /* LED subsystem callbacks */

 static int aat1290_led_brightness_set(struct led_classdev *led_cdev,
 					enum led_brightness brightness)
 {
 	struct led_classdev_flash *fled_cdev = led_cdev_to_fled_cdev(led_cdev);
 	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);

 	mutex_lock(&led->lock);

 	if (brightness == 0) {
 		gpiod_direction_output(led->gpio_fl_en, 0);
 		gpiod_direction_output(led->gpio_en_set, 0);
 		led->movie_mode = false;
 	} else {
 		if (!led->movie_mode) {
 			aat1290_as2cwire_write(led,
 				AAT1290_MM_CURRENT_RATIO_ADDR,
 				AAT1290_MM_TO_FL_1_92);
 			led->movie_mode = true;
 		}

 		aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
 				AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
 		aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
 				AAT1290_MOVIE_MODE_ON);
 	}

 	mutex_unlock(&led->lock);

 	return 0;
 }

 static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 					 bool state)

 {
 	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 	struct led_flash_setting *timeout = &fled_cdev->timeout;

 	mutex_lock(&led->lock);

 	if (state) {
 		aat1290_set_flash_safety_timer(led, timeout->val);
 		gpiod_direction_output(led->gpio_fl_en, 1);
 	} else {
 		gpiod_direction_output(led->gpio_fl_en, 0);
 		gpiod_direction_output(led->gpio_en_set, 0);
 	}

 	/*
 	 * To reenter movie mode after a flash event the part must be cycled
 	 * off and back on to reset the movie mode and reprogrammed via the
 	 * AS2Cwire. Therefore the brightness and movie_mode properties needs
 	 * to be updated here to reflect the actual state.
 	 */
 	led_cdev->brightness = 0;
 	led->movie_mode = false;

 	mutex_unlock(&led->lock);

 	return 0;
 }

 static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 						u32 timeout)
 {
 	/*
 	 * Don't do anything - flash timeout is cached in the led-class-flash
 	 * core and will be applied in the strobe_set op, as writing the
 	 * safety timer register spuriously turns the torch mode on.
 	 */

 	return 0;
 }

 static int aat1290_led_parse_dt(struct aat1290_led *led,
 			struct aat1290_led_config_data *cfg,
 			struct device_node **sub_node)
 {
 	struct device *dev = &led->pdev->dev;
 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 	struct pinctrl *pinctrl;
 #endif
 	int ret = 0;

 	led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
 	if (IS_ERR(led->gpio_fl_en)) {
 		ret = PTR_ERR(led->gpio_fl_en);
 		dev_err(dev, "Unable to claim gpio \"flen\".\n");
 		return ret;
 	}

 	led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
 	if (IS_ERR(led->gpio_en_set)) {
 		ret = PTR_ERR(led->gpio_en_set);
 		dev_err(dev, "Unable to claim gpio \"enset\".\n");
 		return ret;
 	}

 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 	pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
 	if (IS_ERR(pinctrl)) {
 		cfg->has_external_strobe = false;
 		dev_info(dev,
 			 "No support for external strobe detected.\n");
 	} else {
 		cfg->has_external_strobe = true;
 	}
 #endif

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

 	ret = of_property_read_u32(child_node, "led-max-microamp",
 				&cfg->max_mm_current);
 	/*
 	 * led-max-microamp will default to 1/20 of flash-max-microamp
 	 * in case it is missing.
 	 */
 	if (ret < 0)
 		dev_warn(dev,
 			"led-max-microamp DT property missing\n");

 	ret = of_property_read_u32(child_node, "flash-max-microamp",
 				&cfg->max_flash_current);
 	if (ret < 0) {
 		dev_err(dev,
 			"flash-max-microamp DT property missing\n");
 		return ret;
 	}

 	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
 				&cfg->max_flash_tm);
 	if (ret < 0) {
 		dev_err(dev,
 			"flash-max-timeout-us DT property missing\n");
 		return ret;
 	}

 	*sub_node = child_node;

 	return 0;
 }

 static void aat1290_led_validate_mm_current(struct aat1290_led *led,
 					struct aat1290_led_config_data *cfg)
 {
 	int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;

 	while (e - b > 1) {
 		i = b + (e - b) / 2;
 		if (cfg->max_mm_current < led->mm_current_scale[i])
 			e = i;
 		else
 			b = i;
 	}

 	cfg->max_mm_current = led->mm_current_scale[b];
 	cfg->max_brightness = b + 1;
 }

 static int init_mm_current_scale(struct aat1290_led *led,
 			struct aat1290_led_config_data *cfg)
 {
 	static const int max_mm_current_percent[] = {
 		20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
 		63, 71, 79, 89, 100
 	};
 	int i, max_mm_current =
 			AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);

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

 	for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
 		led->mm_current_scale[i] = max_mm_current *
 					  max_mm_current_percent[i] / 100;

 	return 0;
 }

 static int aat1290_led_get_configuration(struct aat1290_led *led,
 					struct aat1290_led_config_data *cfg,
 					struct device_node **sub_node)
 {
 	int ret;

 	ret = aat1290_led_parse_dt(led, cfg, sub_node);
 	if (ret < 0)
 		return ret;
 	/*
 	 * Init non-linear movie mode current scale basing
 	 * on the max flash current from led configuration.
 	 */
 	ret = init_mm_current_scale(led, cfg);
 	if (ret < 0)
 		return ret;

 	aat1290_led_validate_mm_current(led, cfg);

 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 #else
 	devm_kfree(&led->pdev->dev, led->mm_current_scale);
 #endif

 	return 0;
 }

 static void aat1290_init_flash_timeout(struct aat1290_led *led,
 				struct aat1290_led_config_data *cfg)
 {
 	struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 	struct led_flash_setting *setting;

 	/* Init flash timeout setting */
 	setting = &fled_cdev->timeout;
 	setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
 	setting->max = cfg->max_flash_tm;
 	setting->step = setting->min;
 	setting->val = setting->max;
 }

 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 static enum led_brightness aat1290_intensity_to_brightness(
 					struct v4l2_flash *v4l2_flash,
 					s32 intensity)
 {
 	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 	int i;

 	for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
 		if (intensity >= led->mm_current_scale[i])
 			return i + 1;

 	return 1;
 }

 static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
 					enum led_brightness brightness)
 {
 	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);

 	return led->mm_current_scale[brightness - 1];
 }

 static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
 						bool enable)
 {
 	struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
 	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 	struct pinctrl *pinctrl;

 	gpiod_direction_output(led->gpio_fl_en, 0);
 	gpiod_direction_output(led->gpio_en_set, 0);

 	led->movie_mode = false;
 	led_cdev->brightness = 0;

 	pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
 						enable ? "isp" : "host");
 	if (IS_ERR(pinctrl)) {
 		dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
 		return PTR_ERR(pinctrl);
 	}

 	return 0;
 }

 static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
 					struct aat1290_led_config_data *led_cfg,
 					struct v4l2_flash_config *v4l2_sd_cfg)
 {
 	struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 	struct led_flash_setting *s;

 	strscpy(v4l2_sd_cfg->dev_name, led_cdev->dev->kobj.name,
 		sizeof(v4l2_sd_cfg->dev_name));

 	s = &v4l2_sd_cfg->intensity;
 	s->min = led->mm_current_scale[0];
 	s->max = led_cfg->max_mm_current;
 	s->step = 1;
 	s->val = s->max;

 	v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
 }

 static const struct v4l2_flash_ops v4l2_flash_ops = {
 	.external_strobe_set = aat1290_led_external_strobe_set,
 	.intensity_to_led_brightness = aat1290_intensity_to_brightness,
 	.led_brightness_to_intensity = aat1290_brightness_to_intensity,
 };
 #else
 static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
 				struct aat1290_led_config_data *led_cfg,
 				struct v4l2_flash_config *v4l2_sd_cfg)
 {
 }
 static const struct v4l2_flash_ops v4l2_flash_ops;
 #endif

 static const struct led_flash_ops flash_ops = {
 	.strobe_set = aat1290_led_flash_strobe_set,
 	.timeout_set = aat1290_led_flash_timeout_set,
 };

 static int aat1290_led_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *sub_node = NULL;
 	struct aat1290_led *led;
 	struct led_classdev *led_cdev;
 	struct led_classdev_flash *fled_cdev;
 	struct led_init_data init_data = {};
 	struct aat1290_led_config_data led_cfg = {};
 	struct v4l2_flash_config v4l2_sd_cfg = {};
 	int ret;

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

 	led->pdev = pdev;
 	platform_set_drvdata(pdev, led);

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

 	ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
 	if (ret < 0)
 		return ret;

 	mutex_init(&led->lock);

 	/* Initialize LED Flash class device */
 	led_cdev->brightness_set_blocking = aat1290_led_brightness_set;
 	led_cdev->max_brightness = led_cfg.max_brightness;
 	led_cdev->flags |= LED_DEV_CAP_FLASH;

 	aat1290_init_flash_timeout(led, &led_cfg);

 	init_data.fwnode = of_fwnode_handle(sub_node);
 	init_data.devicename = AAT1290_NAME;

 	/* Register LED Flash class device */
 	ret = led_classdev_flash_register_ext(&pdev->dev, fled_cdev,
 					      &init_data);
 	if (ret < 0)
 		goto err_flash_register;

 	aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);

 	/* Create V4L2 Flash subdev. */
 	led->v4l2_flash = v4l2_flash_init(dev, of_fwnode_handle(sub_node),
 					  fled_cdev, &v4l2_flash_ops,
 					  &v4l2_sd_cfg);
 	if (IS_ERR(led->v4l2_flash)) {
 		ret = PTR_ERR(led->v4l2_flash);
 		goto error_v4l2_flash_init;
 	}

 	return 0;

 error_v4l2_flash_init:
 	led_classdev_flash_unregister(fled_cdev);
 err_flash_register:
 	mutex_destroy(&led->lock);

 	return ret;
 }

 static void aat1290_led_remove(struct platform_device *pdev)
 {
 	struct aat1290_led *led = platform_get_drvdata(pdev);

 	v4l2_flash_release(led->v4l2_flash);
 	led_classdev_flash_unregister(&led->fled_cdev);

 	mutex_destroy(&led->lock);
 }

 static const struct of_device_id aat1290_led_dt_match[] = {
 	{ .compatible = "skyworks,aat1290" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);

 static struct platform_driver aat1290_led_driver = {
 	.probe		= aat1290_led_probe,
 	.remove_new	= aat1290_led_remove,
 	.driver		= {
 		.name	= "aat1290",
 		.of_match_table = aat1290_led_dt_match,
 	},
 };

 module_platform_driver(aat1290_led_driver);

 MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
 MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* LED Flash class driver for the AAT1290
	* 1.5A Step-Up Current Regulator for Flash LEDs
	*
	* Copyright (C) 2015, Samsung Electronics Co., Ltd.
	* Author: Jacek Anaszewski <j.anaszewski@samsung.com>
	*/

	#include <linux/cleanup.h>
	#include <linux/delay.h>
	#include <linux/gpio/consumer.h>
	#include <linux/led-class-flash.h>
	#include <linux/leds.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/pinctrl/consumer.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <media/v4l2-flash-led-class.h>

	#define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
	#define AAT1290_MAX_MM_CURR_PERCENT_0 16
	#define AAT1290_MAX_MM_CURR_PERCENT_100 1

	#define AAT1290_FLASH_SAFETY_TIMER_ADDR 18

	#define AAT1290_MOVIE_MODE_CONFIG_ADDR 19
	#define AAT1290_MOVIE_MODE_OFF 1
	#define AAT1290_MOVIE_MODE_ON 3

	#define AAT1290_MM_CURRENT_RATIO_ADDR 20
	#define AAT1290_MM_TO_FL_1_92 1

	#define AAT1290_MM_TO_FL_RATIO 1000 / 1920
	#define AAT1290_MAX_MM_CURRENT(fl_max) (fl_max * AAT1290_MM_TO_FL_RATIO)

	#define AAT1290_LATCH_TIME_MIN_US 500
	#define AAT1290_LATCH_TIME_MAX_US 1000
	#define AAT1290_EN_SET_TICK_TIME_US 1
	#define AAT1290_FLEN_OFF_DELAY_TIME_US 10
	#define AAT1290_FLASH_TM_NUM_LEVELS 16
	#define AAT1290_MM_CURRENT_SCALE_SIZE 15

	#define AAT1290_NAME "aat1290"


	struct aat1290_led_config_data {
	/* maximum LED current in movie mode */
	u32 max_mm_current;
	/* maximum LED current in flash mode */
	u32 max_flash_current;
	/* maximum flash timeout */
	u32 max_flash_tm;
	/* external strobe capability */
	bool has_external_strobe;
	/* max LED brightness level */
	enum led_brightness max_brightness;
	};

	struct aat1290_led {
	/* platform device data */
	struct platform_device *pdev;
	/* secures access to the device */
	struct mutex lock;

	/* corresponding LED Flash class device */
	struct led_classdev_flash fled_cdev;
	/* V4L2 Flash device */
	struct v4l2_flash *v4l2_flash;

	/* FLEN pin */
	struct gpio_desc *gpio_fl_en;
	/* EN\|SET pin */
	struct gpio_desc *gpio_en_set;
	/* movie mode current scale */
	int *mm_current_scale;
	/* device mode */
	bool movie_mode;
	};

	static struct aat1290_led *fled_cdev_to_led(
	struct led_classdev_flash *fled_cdev)
	{
	return container_of(fled_cdev, struct aat1290_led, fled_cdev);
	}

	static struct led_classdev_flash *led_cdev_to_fled_cdev(
	struct led_classdev *led_cdev)
	{
	return container_of(led_cdev, struct led_classdev_flash, led_cdev);
	}

	static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
	{
	int i;

	gpiod_direction_output(led->gpio_fl_en, 0);
	gpiod_direction_output(led->gpio_en_set, 0);

	udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);

	/* write address */
	for (i = 0; i < addr; ++i) {
	udelay(AAT1290_EN_SET_TICK_TIME_US);
	gpiod_direction_output(led->gpio_en_set, 0);
	udelay(AAT1290_EN_SET_TICK_TIME_US);
	gpiod_direction_output(led->gpio_en_set, 1);
	}

	usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);

	/* write data */
	for (i = 0; i < value; ++i) {
	udelay(AAT1290_EN_SET_TICK_TIME_US);
	gpiod_direction_output(led->gpio_en_set, 0);
	udelay(AAT1290_EN_SET_TICK_TIME_US);
	gpiod_direction_output(led->gpio_en_set, 1);
	}

	usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
	}

	static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
	unsigned int micro_sec)
	{
	struct led_classdev_flash *fled_cdev = &led->fled_cdev;
	struct led_flash_setting *flash_tm = &fled_cdev->timeout;
	int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
	(micro_sec / flash_tm->step) + 1;

	aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
	flash_tm_reg);
	}

	/* LED subsystem callbacks */

	static int aat1290_led_brightness_set(struct led_classdev *led_cdev,
	enum led_brightness brightness)
	{
	struct led_classdev_flash *fled_cdev = led_cdev_to_fled_cdev(led_cdev);
	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);

	mutex_lock(&led->lock);

	if (brightness == 0) {
	gpiod_direction_output(led->gpio_fl_en, 0);
	gpiod_direction_output(led->gpio_en_set, 0);
	led->movie_mode = false;
	} else {
	if (!led->movie_mode) {
	aat1290_as2cwire_write(led,
	AAT1290_MM_CURRENT_RATIO_ADDR,
	AAT1290_MM_TO_FL_1_92);
	led->movie_mode = true;
	}

	aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
	AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
	aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
	AAT1290_MOVIE_MODE_ON);
	}

	mutex_unlock(&led->lock);

	return 0;
	}

	static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
	bool state)

	{
	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
	struct led_flash_setting *timeout = &fled_cdev->timeout;

	mutex_lock(&led->lock);

	if (state) {
	aat1290_set_flash_safety_timer(led, timeout->val);
	gpiod_direction_output(led->gpio_fl_en, 1);
	} else {
	gpiod_direction_output(led->gpio_fl_en, 0);
	gpiod_direction_output(led->gpio_en_set, 0);
	}

	/*
	* To reenter movie mode after a flash event the part must be cycled
	* off and back on to reset the movie mode and reprogrammed via the
	* AS2Cwire. Therefore the brightness and movie_mode properties needs
	* to be updated here to reflect the actual state.
	*/
	led_cdev->brightness = 0;
	led->movie_mode = false;

	mutex_unlock(&led->lock);

	return 0;
	}

	static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
	u32 timeout)
	{
	/*
	* Don't do anything - flash timeout is cached in the led-class-flash
	* core and will be applied in the strobe_set op, as writing the
	* safety timer register spuriously turns the torch mode on.
	*/

	return 0;
	}

	static int aat1290_led_parse_dt(struct aat1290_led *led,
	struct aat1290_led_config_data *cfg,
	struct device_node **sub_node)
	{
	struct device *dev = &led->pdev->dev;
	#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
	struct pinctrl *pinctrl;
	#endif
	int ret = 0;

	led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
	if (IS_ERR(led->gpio_fl_en)) {
	ret = PTR_ERR(led->gpio_fl_en);
	dev_err(dev, "Unable to claim gpio \"flen\".\n");
	return ret;
	}

	led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
	if (IS_ERR(led->gpio_en_set)) {
	ret = PTR_ERR(led->gpio_en_set);
	dev_err(dev, "Unable to claim gpio \"enset\".\n");
	return ret;
	}

	#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
	pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
	if (IS_ERR(pinctrl)) {
	cfg->has_external_strobe = false;
	dev_info(dev,
	"No support for external strobe detected.\n");
	} else {
	cfg->has_external_strobe = true;
	}
	#endif

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

	ret = of_property_read_u32(child_node, "led-max-microamp",
	&cfg->max_mm_current);
	/*
	* led-max-microamp will default to 1/20 of flash-max-microamp
	* in case it is missing.
	*/
	if (ret < 0)
	dev_warn(dev,
	"led-max-microamp DT property missing\n");

	ret = of_property_read_u32(child_node, "flash-max-microamp",
	&cfg->max_flash_current);
	if (ret < 0) {
	dev_err(dev,
	"flash-max-microamp DT property missing\n");
	return ret;
	}

	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
	&cfg->max_flash_tm);
	if (ret < 0) {
	dev_err(dev,
	"flash-max-timeout-us DT property missing\n");
	return ret;
	}

	*sub_node = child_node;

	return 0;
	}

	static void aat1290_led_validate_mm_current(struct aat1290_led *led,
	struct aat1290_led_config_data *cfg)
	{
	int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;

	while (e - b > 1) {
	i = b + (e - b) / 2;
	if (cfg->max_mm_current < led->mm_current_scale[i])
	e = i;
	else
	b = i;
	}

	cfg->max_mm_current = led->mm_current_scale[b];
	cfg->max_brightness = b + 1;
	}

	static int init_mm_current_scale(struct aat1290_led *led,
	struct aat1290_led_config_data *cfg)
	{
	static const int max_mm_current_percent[] = {
	20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
	63, 71, 79, 89, 100
	};
	int i, max_mm_current =
	AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);

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

	for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
	led->mm_current_scale[i] = max_mm_current *
	max_mm_current_percent[i] / 100;

	return 0;
	}

	static int aat1290_led_get_configuration(struct aat1290_led *led,
	struct aat1290_led_config_data *cfg,
	struct device_node **sub_node)
	{
	int ret;

	ret = aat1290_led_parse_dt(led, cfg, sub_node);
	if (ret < 0)
	return ret;
	/*
	* Init non-linear movie mode current scale basing
	* on the max flash current from led configuration.
	*/
	ret = init_mm_current_scale(led, cfg);
	if (ret < 0)
	return ret;

	aat1290_led_validate_mm_current(led, cfg);

	#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
	#else
	devm_kfree(&led->pdev->dev, led->mm_current_scale);
	#endif

	return 0;
	}

	static void aat1290_init_flash_timeout(struct aat1290_led *led,
	struct aat1290_led_config_data *cfg)
	{
	struct led_classdev_flash *fled_cdev = &led->fled_cdev;
	struct led_flash_setting *setting;

	/* Init flash timeout setting */
	setting = &fled_cdev->timeout;
	setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
	setting->max = cfg->max_flash_tm;
	setting->step = setting->min;
	setting->val = setting->max;
	}

	#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
	static enum led_brightness aat1290_intensity_to_brightness(
	struct v4l2_flash *v4l2_flash,
	s32 intensity)
	{
	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
	int i;

	for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
	if (intensity >= led->mm_current_scale[i])
	return i + 1;

	return 1;
	}

	static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
	enum led_brightness brightness)
	{
	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);

	return led->mm_current_scale[brightness - 1];
	}

	static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
	bool enable)
	{
	struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
	struct pinctrl *pinctrl;

	gpiod_direction_output(led->gpio_fl_en, 0);
	gpiod_direction_output(led->gpio_en_set, 0);

	led->movie_mode = false;
	led_cdev->brightness = 0;

	pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
	enable ? "isp" : "host");
	if (IS_ERR(pinctrl)) {
	dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
	return PTR_ERR(pinctrl);
	}

	return 0;
	}

	static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
	struct aat1290_led_config_data *led_cfg,
	struct v4l2_flash_config *v4l2_sd_cfg)
	{
	struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
	struct led_flash_setting *s;

	strscpy(v4l2_sd_cfg->dev_name, led_cdev->dev->kobj.name,
	sizeof(v4l2_sd_cfg->dev_name));

	s = &v4l2_sd_cfg->intensity;
	s->min = led->mm_current_scale[0];
	s->max = led_cfg->max_mm_current;
	s->step = 1;
	s->val = s->max;

	v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
	}

	static const struct v4l2_flash_ops v4l2_flash_ops = {
	.external_strobe_set = aat1290_led_external_strobe_set,
	.intensity_to_led_brightness = aat1290_intensity_to_brightness,
	.led_brightness_to_intensity = aat1290_brightness_to_intensity,
	};
	#else
	static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
	struct aat1290_led_config_data *led_cfg,
	struct v4l2_flash_config *v4l2_sd_cfg)
	{
	}
	static const struct v4l2_flash_ops v4l2_flash_ops;
	#endif

	static const struct led_flash_ops flash_ops = {
	.strobe_set = aat1290_led_flash_strobe_set,
	.timeout_set = aat1290_led_flash_timeout_set,
	};

	static int aat1290_led_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct device_node *sub_node = NULL;
	struct aat1290_led *led;
	struct led_classdev *led_cdev;
	struct led_classdev_flash *fled_cdev;
	struct led_init_data init_data = {};
	struct aat1290_led_config_data led_cfg = {};
	struct v4l2_flash_config v4l2_sd_cfg = {};
	int ret;

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

	led->pdev = pdev;
	platform_set_drvdata(pdev, led);

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

	ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
	if (ret < 0)
	return ret;

	mutex_init(&led->lock);

	/* Initialize LED Flash class device */
	led_cdev->brightness_set_blocking = aat1290_led_brightness_set;
	led_cdev->max_brightness = led_cfg.max_brightness;
	led_cdev->flags \|= LED_DEV_CAP_FLASH;

	aat1290_init_flash_timeout(led, &led_cfg);

	init_data.fwnode = of_fwnode_handle(sub_node);
	init_data.devicename = AAT1290_NAME;

	/* Register LED Flash class device */
	ret = led_classdev_flash_register_ext(&pdev->dev, fled_cdev,
	&init_data);
	if (ret < 0)
	goto err_flash_register;

	aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);

	/* Create V4L2 Flash subdev. */
	led->v4l2_flash = v4l2_flash_init(dev, of_fwnode_handle(sub_node),
	fled_cdev, &v4l2_flash_ops,
	&v4l2_sd_cfg);
	if (IS_ERR(led->v4l2_flash)) {
	ret = PTR_ERR(led->v4l2_flash);
	goto error_v4l2_flash_init;
	}

	return 0;

	error_v4l2_flash_init:
	led_classdev_flash_unregister(fled_cdev);
	err_flash_register:
	mutex_destroy(&led->lock);

	return ret;
	}

	static void aat1290_led_remove(struct platform_device *pdev)
	{
	struct aat1290_led *led = platform_get_drvdata(pdev);

	v4l2_flash_release(led->v4l2_flash);
	led_classdev_flash_unregister(&led->fled_cdev);

	mutex_destroy(&led->lock);
	}

	static const struct of_device_id aat1290_led_dt_match[] = {
	{ .compatible = "skyworks,aat1290" },
	{},
	};
	MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);

	static struct platform_driver aat1290_led_driver = {
	.probe = aat1290_led_probe,
	.remove_new = aat1290_led_remove,
	.driver = {
	.name = "aat1290",
	.of_match_table = aat1290_led_dt_match,
	},
	};

	module_platform_driver(aat1290_led_driver);

	MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
	MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
	MODULE_LICENSE("GPL v2");