leds: aat1290: add support for V4L2 Flash sub-device

Add support for V4L2 Flash sub-device to the aat1290 LED Flash class
driver. The support allows for V4L2 Flash sub-device to take the control
of the LED Flash class device.
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Bryan Wu <cooloney@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/Kconfig

@@ -47,6 +47,7 @@ config LEDS_AAT1290
 	depends on LEDS_CLASS_FLASH
 	depends on GPIOLIB
 	depends on OF
+	depends on PINCTRL
 	help
 	 This option enables support for the LEDs on the AAT1290.
 

drivers/leds/leds-aat1290.c

@@ -17,9 +17,11 @@
 #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 <linux/workqueue.h>
+#include <media/v4l2-flash-led-class.h>
 
 #define AAT1290_MOVIE_MODE_CURRENT_ADDR	17
 #define AAT1290_MAX_MM_CURR_PERCENT_0	16
@@ -52,6 +54,8 @@ struct aat1290_led_config_data {
 	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;
 };
@@ -64,6 +68,8 @@ struct aat1290_led {
 
 	/* 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;
@@ -230,11 +236,15 @@ static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 }
 
 static int aat1290_led_parse_dt(struct aat1290_led *led,
-			struct aat1290_led_config_data *cfg)
+			struct aat1290_led_config_data *cfg,
+			struct device_node **sub_node)
 {
 	struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 	struct device *dev = &led->pdev->dev;
 	struct device_node *child_node;
+#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
+	struct pinctrl *pinctrl;
+#endif
 	int ret = 0;
 
 	led->gpio_fl_en = devm_gpiod_get(dev, "flen");
@@ -251,6 +261,17 @@ static int aat1290_led_parse_dt(struct aat1290_led *led,
 		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
+
 	child_node = of_get_next_available_child(dev->of_node, NULL);
 	if (!child_node) {
 		dev_err(dev, "No DT child node found for connected LED.\n");
@@ -288,6 +309,8 @@ static int aat1290_led_parse_dt(struct aat1290_led *led,
 
 	of_node_put(child_node);
 
+	*sub_node = child_node;
+
 	return ret;
 }
 
@@ -316,7 +339,8 @@ int init_mm_current_scale(struct aat1290_led *led,
 	int i, max_mm_current =
 			AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
 
-	led->mm_current_scale = kzalloc(sizeof(max_mm_current_percent),
+	led->mm_current_scale = devm_kzalloc(&led->pdev->dev,
+					sizeof(max_mm_current_percent),
 					GFP_KERNEL);
 	if (!led->mm_current_scale)
 		return -ENOMEM;
@@ -329,11 +353,12 @@ int init_mm_current_scale(struct aat1290_led *led,
 }
 
 static int aat1290_led_get_configuration(struct aat1290_led *led,
-					struct aat1290_led_config_data *cfg)
+					struct aat1290_led_config_data *cfg,
+					struct device_node **sub_node)
 {
 	int ret;
 
-	ret = aat1290_led_parse_dt(led, cfg);
+	ret = aat1290_led_parse_dt(led, cfg, sub_node);
 	if (ret < 0)
 		return ret;
 	/*
@@ -346,7 +371,10 @@ static int aat1290_led_get_configuration(struct aat1290_led *led,
 
 	aat1290_led_validate_mm_current(led, cfg);
 
-	kfree(led->mm_current_scale);
+#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
+#else
+	devm_kfree(&led->pdev->dev, led->mm_current_scale);
+#endif
 
 	return 0;
 }
@@ -365,6 +393,88 @@ static void aat1290_init_flash_timeout(struct aat1290_led *led,
 	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;
+
+	strlcpy(v4l2_sd_cfg->dev_name, led_cdev->name,
+		sizeof(v4l2_sd_cfg->dev_name));
+
+	s = &v4l2_sd_cfg->torch_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,
@@ -373,10 +483,12 @@ static const struct led_flash_ops flash_ops = {
 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 aat1290_led_config_data led_cfg = {};
+	struct v4l2_flash_config v4l2_sd_cfg = {};
 	int ret;
 
 	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
@@ -390,7 +502,7 @@ static int aat1290_led_probe(struct platform_device *pdev)
 	fled_cdev->ops = &flash_ops;
 	led_cdev = &fled_cdev->led_cdev;
 
-	ret = aat1290_led_get_configuration(led, &led_cfg);
+	ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
 	if (ret < 0)
 		return ret;
 
@@ -410,8 +522,20 @@ static int aat1290_led_probe(struct platform_device *pdev)
 	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, sub_node, fled_cdev, NULL,
+					  &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);
 
@@ -422,6 +546,7 @@ static int 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);
 	cancel_work_sync(&led->work_brightness_set);