| // SPDX-License-Identifier: GPL-2.0-or-later | 
 | /* | 
 |  * LED driver for Richtek RT8515 flash/torch white LEDs | 
 |  * found on some Samsung mobile phones. | 
 |  * | 
 |  * This is a 1.5A Boost dual channel driver produced around 2011. | 
 |  * | 
 |  * The component lacks a datasheet, but in the schematic picture | 
 |  * from the LG P970 service manual you can see the connections | 
 |  * from the RT8515 to the LED, with two resistors connected | 
 |  * from the pins "RFS" and "RTS" to ground. | 
 |  * | 
 |  * On the LG P970: | 
 |  * RFS (resistance flash setting?) is 20 kOhm | 
 |  * RTS (resistance torch setting?) is 39 kOhm | 
 |  * | 
 |  * Some sleuthing finds us the RT9387A which we have a datasheet for: | 
 |  * https://static5.arrow.com/pdfs/2014/7/27/8/21/12/794/rtt_/manual/94download_ds.jspprt9387a.jspprt9387a.pdf | 
 |  * This apparently works the same way so in theory this driver | 
 |  * should cover RT9387A as well. This has not been tested, please | 
 |  * update the compatibles if you add RT9387A support. | 
 |  * | 
 |  * Linus Walleij <linus.walleij@linaro.org> | 
 |  */ | 
 | #include <linux/delay.h> | 
 | #include <linux/err.h> | 
 | #include <linux/gpio/consumer.h> | 
 | #include <linux/led-class-flash.h> | 
 | #include <linux/mod_devicetable.h> | 
 | #include <linux/module.h> | 
 | #include <linux/platform_device.h> | 
 | #include <linux/property.h> | 
 | #include <linux/regulator/consumer.h> | 
 |  | 
 | #include <media/v4l2-flash-led-class.h> | 
 |  | 
 | /* We can provide 15-700 mA out to the LED */ | 
 | #define RT8515_MIN_IOUT_MA	15 | 
 | #define RT8515_MAX_IOUT_MA	700 | 
 | /* The maximum intensity is 1-16 for flash and 1-100 for torch */ | 
 | #define RT8515_FLASH_MAX	16 | 
 | #define RT8515_TORCH_MAX	100 | 
 |  | 
 | #define RT8515_TIMEOUT_US	250000U | 
 | #define RT8515_MAX_TIMEOUT_US	300000U | 
 |  | 
 | struct rt8515 { | 
 | 	struct led_classdev_flash fled; | 
 | 	struct device *dev; | 
 | 	struct v4l2_flash *v4l2_flash; | 
 | 	struct mutex lock; | 
 | 	struct regulator *reg; | 
 | 	struct gpio_desc *enable_torch; | 
 | 	struct gpio_desc *enable_flash; | 
 | 	struct timer_list powerdown_timer; | 
 | 	u32 max_timeout; /* Flash max timeout */ | 
 | 	int flash_max_intensity; | 
 | 	int torch_max_intensity; | 
 | }; | 
 |  | 
 | static struct rt8515 *to_rt8515(struct led_classdev_flash *fled) | 
 | { | 
 | 	return container_of(fled, struct rt8515, fled); | 
 | } | 
 |  | 
 | static void rt8515_gpio_led_off(struct rt8515 *rt) | 
 | { | 
 | 	gpiod_set_value(rt->enable_flash, 0); | 
 | 	gpiod_set_value(rt->enable_torch, 0); | 
 | } | 
 |  | 
 | static void rt8515_gpio_brightness_commit(struct gpio_desc *gpiod, | 
 | 					  int brightness) | 
 | { | 
 | 	int i; | 
 |  | 
 | 	/* | 
 | 	 * Toggling a GPIO line with a small delay increases the | 
 | 	 * brightness one step at a time. | 
 | 	 */ | 
 | 	for (i = 0; i < brightness; i++) { | 
 | 		gpiod_set_value(gpiod, 0); | 
 | 		udelay(1); | 
 | 		gpiod_set_value(gpiod, 1); | 
 | 		udelay(1); | 
 | 	} | 
 | } | 
 |  | 
 | /* This is setting the torch light level */ | 
 | static int rt8515_led_brightness_set(struct led_classdev *led, | 
 | 				     enum led_brightness brightness) | 
 | { | 
 | 	struct led_classdev_flash *fled = lcdev_to_flcdev(led); | 
 | 	struct rt8515 *rt = to_rt8515(fled); | 
 |  | 
 | 	mutex_lock(&rt->lock); | 
 |  | 
 | 	if (brightness == LED_OFF) { | 
 | 		/* Off */ | 
 | 		rt8515_gpio_led_off(rt); | 
 | 	} else if (brightness < RT8515_TORCH_MAX) { | 
 | 		/* Step it up to movie mode brightness using the flash pin */ | 
 | 		rt8515_gpio_brightness_commit(rt->enable_torch, brightness); | 
 | 	} else { | 
 | 		/* Max torch brightness requested */ | 
 | 		gpiod_set_value(rt->enable_torch, 1); | 
 | 	} | 
 |  | 
 | 	mutex_unlock(&rt->lock); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int rt8515_led_flash_strobe_set(struct led_classdev_flash *fled, | 
 | 				       bool state) | 
 | { | 
 | 	struct rt8515 *rt = to_rt8515(fled); | 
 | 	struct led_flash_setting *timeout = &fled->timeout; | 
 | 	int brightness = rt->flash_max_intensity; | 
 |  | 
 | 	mutex_lock(&rt->lock); | 
 |  | 
 | 	if (state) { | 
 | 		/* Enable LED flash mode and set brightness */ | 
 | 		rt8515_gpio_brightness_commit(rt->enable_flash, brightness); | 
 | 		/* Set timeout */ | 
 | 		mod_timer(&rt->powerdown_timer, | 
 | 			  jiffies + usecs_to_jiffies(timeout->val)); | 
 | 	} else { | 
 | 		del_timer_sync(&rt->powerdown_timer); | 
 | 		/* Turn the LED off */ | 
 | 		rt8515_gpio_led_off(rt); | 
 | 	} | 
 |  | 
 | 	fled->led_cdev.brightness = LED_OFF; | 
 | 	/* After this the torch LED will be disabled */ | 
 |  | 
 | 	mutex_unlock(&rt->lock); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int rt8515_led_flash_strobe_get(struct led_classdev_flash *fled, | 
 | 				       bool *state) | 
 | { | 
 | 	struct rt8515 *rt = to_rt8515(fled); | 
 |  | 
 | 	*state = timer_pending(&rt->powerdown_timer); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int rt8515_led_flash_timeout_set(struct led_classdev_flash *fled, | 
 | 					u32 timeout) | 
 | { | 
 | 	/* The timeout is stored in the led-class-flash core */ | 
 | 	return 0; | 
 | } | 
 |  | 
 | static const struct led_flash_ops rt8515_flash_ops = { | 
 | 	.strobe_set = rt8515_led_flash_strobe_set, | 
 | 	.strobe_get = rt8515_led_flash_strobe_get, | 
 | 	.timeout_set = rt8515_led_flash_timeout_set, | 
 | }; | 
 |  | 
 | static void rt8515_powerdown_timer(struct timer_list *t) | 
 | { | 
 | 	struct rt8515 *rt = from_timer(rt, t, powerdown_timer); | 
 |  | 
 | 	/* Turn the LED off */ | 
 | 	rt8515_gpio_led_off(rt); | 
 | } | 
 |  | 
 | static void rt8515_init_flash_timeout(struct rt8515 *rt) | 
 | { | 
 | 	struct led_classdev_flash *fled = &rt->fled; | 
 | 	struct led_flash_setting *s; | 
 |  | 
 | 	/* Init flash timeout setting */ | 
 | 	s = &fled->timeout; | 
 | 	s->min = 1; | 
 | 	s->max = rt->max_timeout; | 
 | 	s->step = 1; | 
 | 	/* | 
 | 	 * Set default timeout to RT8515_TIMEOUT_US except if | 
 | 	 * max_timeout from DT is lower. | 
 | 	 */ | 
 | 	s->val = min(rt->max_timeout, RT8515_TIMEOUT_US); | 
 | } | 
 |  | 
 | #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS) | 
 | /* Configure the V2L2 flash subdevice */ | 
 | static void rt8515_init_v4l2_flash_config(struct rt8515 *rt, | 
 | 					  struct v4l2_flash_config *v4l2_sd_cfg) | 
 | { | 
 | 	struct led_classdev *led = &rt->fled.led_cdev; | 
 | 	struct led_flash_setting *s; | 
 |  | 
 | 	strscpy(v4l2_sd_cfg->dev_name, led->dev->kobj.name, | 
 | 		sizeof(v4l2_sd_cfg->dev_name)); | 
 |  | 
 | 	/* | 
 | 	 * Init flash intensity setting: this is a linear scale | 
 | 	 * capped from the device tree max intensity setting | 
 | 	 * 1..flash_max_intensity | 
 | 	 */ | 
 | 	s = &v4l2_sd_cfg->intensity; | 
 | 	s->min = 1; | 
 | 	s->max = rt->flash_max_intensity; | 
 | 	s->step = 1; | 
 | 	s->val = s->max; | 
 | } | 
 |  | 
 | static void rt8515_v4l2_flash_release(struct rt8515 *rt) | 
 | { | 
 | 	v4l2_flash_release(rt->v4l2_flash); | 
 | } | 
 |  | 
 | #else | 
 | static void rt8515_init_v4l2_flash_config(struct rt8515 *rt, | 
 | 					  struct v4l2_flash_config *v4l2_sd_cfg) | 
 | { | 
 | } | 
 |  | 
 | static void rt8515_v4l2_flash_release(struct rt8515 *rt) | 
 | { | 
 | } | 
 | #endif | 
 |  | 
 | static void rt8515_determine_max_intensity(struct rt8515 *rt, | 
 | 					   struct fwnode_handle *led, | 
 | 					   const char *resistance, | 
 | 					   const char *max_ua_prop, int hw_max, | 
 | 					   int *max_intensity_setting) | 
 | { | 
 | 	u32 res = 0; /* Can't be 0 so 0 is undefined */ | 
 | 	u32 ua; | 
 | 	u32 max_ma; | 
 | 	int max_intensity; | 
 | 	int ret; | 
 |  | 
 | 	fwnode_property_read_u32(rt->dev->fwnode, resistance, &res); | 
 | 	ret = fwnode_property_read_u32(led, max_ua_prop, &ua); | 
 |  | 
 | 	/* Missing info in DT, OK go with hardware maxima */ | 
 | 	if (ret || res == 0) { | 
 | 		dev_err(rt->dev, | 
 | 			"either %s or %s missing from DT, using HW max\n", | 
 | 			resistance, max_ua_prop); | 
 | 		max_ma = RT8515_MAX_IOUT_MA; | 
 | 		max_intensity = hw_max; | 
 | 		goto out_assign_max; | 
 | 	} | 
 |  | 
 | 	/* | 
 | 	 * Formula from the datasheet, this is the maximum current | 
 | 	 * defined by the hardware. | 
 | 	 */ | 
 | 	max_ma = (5500 * 1000) / res; | 
 | 	/* | 
 | 	 * Calculate max intensity (linear scaling) | 
 | 	 * Formula is ((ua / 1000) / max_ma) * 100, then simplified | 
 | 	 */ | 
 | 	max_intensity = (ua / 10) / max_ma; | 
 |  | 
 | 	dev_info(rt->dev, | 
 | 		 "current restricted from %u to %u mA, max intensity %d/100\n", | 
 | 		 max_ma, (ua / 1000), max_intensity); | 
 |  | 
 | out_assign_max: | 
 | 	dev_info(rt->dev, "max intensity %d/%d = %d mA\n", | 
 | 		 max_intensity, hw_max, max_ma); | 
 | 	*max_intensity_setting = max_intensity; | 
 | } | 
 |  | 
 | static int rt8515_probe(struct platform_device *pdev) | 
 | { | 
 | 	struct device *dev = &pdev->dev; | 
 | 	struct fwnode_handle *child; | 
 | 	struct rt8515 *rt; | 
 | 	struct led_classdev *led; | 
 | 	struct led_classdev_flash *fled; | 
 | 	struct led_init_data init_data = {}; | 
 | 	struct v4l2_flash_config v4l2_sd_cfg = {}; | 
 | 	int ret; | 
 |  | 
 | 	rt = devm_kzalloc(dev, sizeof(*rt), GFP_KERNEL); | 
 | 	if (!rt) | 
 | 		return -ENOMEM; | 
 |  | 
 | 	rt->dev = dev; | 
 | 	fled = &rt->fled; | 
 | 	led = &fled->led_cdev; | 
 |  | 
 | 	/* ENF - Enable Flash line */ | 
 | 	rt->enable_flash = devm_gpiod_get(dev, "enf", GPIOD_OUT_LOW); | 
 | 	if (IS_ERR(rt->enable_flash)) | 
 | 		return dev_err_probe(dev, PTR_ERR(rt->enable_flash), | 
 | 				     "cannot get ENF (enable flash) GPIO\n"); | 
 |  | 
 | 	/* ENT - Enable Torch line */ | 
 | 	rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW); | 
 | 	if (IS_ERR(rt->enable_torch)) | 
 | 		return dev_err_probe(dev, PTR_ERR(rt->enable_torch), | 
 | 				     "cannot get ENT (enable torch) GPIO\n"); | 
 |  | 
 | 	child = fwnode_get_next_available_child_node(dev->fwnode, NULL); | 
 | 	if (!child) { | 
 | 		dev_err(dev, | 
 | 			"No fwnode child node found for connected LED.\n"); | 
 | 		return -EINVAL; | 
 | 	} | 
 | 	init_data.fwnode = child; | 
 |  | 
 | 	rt8515_determine_max_intensity(rt, child, "richtek,rfs-ohms", | 
 | 				       "flash-max-microamp", | 
 | 				       RT8515_FLASH_MAX, | 
 | 				       &rt->flash_max_intensity); | 
 | 	rt8515_determine_max_intensity(rt, child, "richtek,rts-ohms", | 
 | 				       "led-max-microamp", | 
 | 				       RT8515_TORCH_MAX, | 
 | 				       &rt->torch_max_intensity); | 
 |  | 
 | 	ret = fwnode_property_read_u32(child, "flash-max-timeout-us", | 
 | 				       &rt->max_timeout); | 
 | 	if (ret) { | 
 | 		rt->max_timeout = RT8515_MAX_TIMEOUT_US; | 
 | 		dev_warn(dev, | 
 | 			 "flash-max-timeout-us property missing\n"); | 
 | 	} | 
 | 	timer_setup(&rt->powerdown_timer, rt8515_powerdown_timer, 0); | 
 | 	rt8515_init_flash_timeout(rt); | 
 |  | 
 | 	fled->ops = &rt8515_flash_ops; | 
 |  | 
 | 	led->max_brightness = rt->torch_max_intensity; | 
 | 	led->brightness_set_blocking = rt8515_led_brightness_set; | 
 | 	led->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH; | 
 |  | 
 | 	mutex_init(&rt->lock); | 
 |  | 
 | 	platform_set_drvdata(pdev, rt); | 
 |  | 
 | 	ret = devm_led_classdev_flash_register_ext(dev, fled, &init_data); | 
 | 	if (ret) { | 
 | 		fwnode_handle_put(child); | 
 | 		mutex_destroy(&rt->lock); | 
 | 		dev_err(dev, "can't register LED %s\n", led->name); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	rt8515_init_v4l2_flash_config(rt, &v4l2_sd_cfg); | 
 |  | 
 | 	/* Create a V4L2 Flash device if V4L2 flash is enabled */ | 
 | 	rt->v4l2_flash = v4l2_flash_init(dev, child, fled, NULL, &v4l2_sd_cfg); | 
 | 	if (IS_ERR(rt->v4l2_flash)) { | 
 | 		ret = PTR_ERR(rt->v4l2_flash); | 
 | 		dev_err(dev, "failed to register V4L2 flash device (%d)\n", | 
 | 			ret); | 
 | 		/* | 
 | 		 * Continue without the V4L2 flash | 
 | 		 * (we still have the classdev) | 
 | 		 */ | 
 | 	} | 
 |  | 
 | 	fwnode_handle_put(child); | 
 | 	return 0; | 
 | } | 
 |  | 
 | static void rt8515_remove(struct platform_device *pdev) | 
 | { | 
 | 	struct rt8515 *rt = platform_get_drvdata(pdev); | 
 |  | 
 | 	rt8515_v4l2_flash_release(rt); | 
 | 	del_timer_sync(&rt->powerdown_timer); | 
 | 	mutex_destroy(&rt->lock); | 
 | } | 
 |  | 
 | static const struct of_device_id rt8515_match[] = { | 
 | 	{ .compatible = "richtek,rt8515", }, | 
 | 	{ /* sentinel */ } | 
 | }; | 
 | MODULE_DEVICE_TABLE(of, rt8515_match); | 
 |  | 
 | static struct platform_driver rt8515_driver = { | 
 | 	.driver = { | 
 | 		.name  = "rt8515", | 
 | 		.of_match_table = rt8515_match, | 
 | 	}, | 
 | 	.probe  = rt8515_probe, | 
 | 	.remove_new = rt8515_remove, | 
 | }; | 
 | module_platform_driver(rt8515_driver); | 
 |  | 
 | MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>"); | 
 | MODULE_DESCRIPTION("Richtek RT8515 LED driver"); | 
 | MODULE_LICENSE("GPL"); |