[PATCH/RFC v4 15/21] media: Add registration helpers for V4L2 flash

[Jacek Anaszewski]

This patch adds helper functions for registering/unregistering
LED class flash devices as V4L2 subdevs. The functions should
be called from the LED subsystem device driver. In case the
support for V4L2 Flash sub-devices is disabled in the kernel
config the functions' empty versions will be used.

Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Sakari Ailus <sakari.ailus@xxxxxx>
Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
 drivers/media/v4l2-core/Kconfig      |   11 +
 drivers/media/v4l2-core/Makefile     |    2 +
 drivers/media/v4l2-core/v4l2-flash.c |  580 ++++++++++++++++++++++++++++++++++
 include/media/v4l2-flash.h           |  137 ++++++++
 4 files changed, 730 insertions(+)
 create mode 100644 drivers/media/v4l2-core/v4l2-flash.c
 create mode 100644 include/media/v4l2-flash.h

diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
index 9ca0f8d..3ae3f0f 100644
--- a/drivers/media/v4l2-core/Kconfig
+++ b/drivers/media/v4l2-core/Kconfig
@@ -35,6 +35,17 @@ config V4L2_MEM2MEM_DEV
         tristate
         depends on VIDEOBUF2_CORE
 
+# Used by LED subsystem flash drivers
+config V4L2_FLASH_LED_CLASS
+	bool "Enable support for Flash sub-devices"
+	depends on VIDEO_V4L2_SUBDEV_API
+	depends on LEDS_CLASS_FLASH
+	---help---
+	  Say Y here to enable support for Flash sub-devices, which allow
+	  to control LED class devices with use of V4L2 Flash controls.
+
+	  When in doubt, say N.
+
 # Used by drivers that need Videobuf modules
 config VIDEOBUF_GEN
 	tristate
diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile
index 63d29f2..44e858c 100644
--- a/drivers/media/v4l2-core/Makefile
+++ b/drivers/media/v4l2-core/Makefile
@@ -22,6 +22,8 @@ obj-$(CONFIG_VIDEO_TUNER) += tuner.o
 
 obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
 
+obj-$(CONFIG_V4L2_FLASH_LED_CLASS) += v4l2-flash.o
+
 obj-$(CONFIG_VIDEOBUF_GEN) += videobuf-core.o
 obj-$(CONFIG_VIDEOBUF_DMA_SG) += videobuf-dma-sg.o
 obj-$(CONFIG_VIDEOBUF_DMA_CONTIG) += videobuf-dma-contig.o
diff --git a/drivers/media/v4l2-core/v4l2-flash.c b/drivers/media/v4l2-core/v4l2-flash.c
new file mode 100644
index 0000000..21080c6
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-flash.c
@@ -0,0 +1,580 @@
+/*
+ * V4L2 Flash LED sub-device registration helpers.
+ *
+ *	Copyright (C) 2014 Samsung Electronics Co., Ltd
+ *	Author: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
+ *
+ * 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/led-class-flash.h>
+#include <linux/mutex.h>
+#include <linux/of_led_flash_manager.h>
+#include <linux/slab.h>
+#include <media/v4l2-flash.h>
+
+#define call_flash_op(v4l2_flash, op, args...)			\
+		(v4l2_flash->ops->op  ?				\
+			v4l2_flash->ops->op(args) :		\
+			-EINVAL)
+
+static struct v4l2_device *v4l2_dev;
+static int registered_flashes;
+
+static inline enum led_brightness v4l2_flash_intensity_to_led_brightness(
+					struct v4l2_ctrl_config *config,
+					s32 intensity)
+{
+	return ((intensity - config->min) / config->step) + 1;
+}
+
+static inline s32 v4l2_flash_led_brightness_to_intensity(
+					struct v4l2_ctrl_config *config,
+					enum led_brightness brightness)
+{
+	return ((brightness - 1) * config->step) + config->min;
+}
+
+static int v4l2_flash_g_volatile_ctrl(struct v4l2_ctrl *c)
+
+{
+	struct v4l2_flash *v4l2_flash = v4l2_ctrl_to_v4l2_flash(c);
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	struct led_classdev *led_cdev = &flash->led_cdev;
+	struct v4l2_flash_ctrl_config *config = &v4l2_flash->config;
+	struct v4l2_flash_ctrl *ctrl = &v4l2_flash->ctrl;
+	bool is_strobing;
+	int ret;
+
+	switch (c->id) {
+	case V4L2_CID_FLASH_TORCH_INTENSITY:
+		/*
+		 * Update torch brightness only if in TORCH_MODE,
+		 * as otherwise brightness_update op returns 0,
+		 * which would spuriously inform user space that
+		 * V4L2_CID_FLASH_TORCH_INTENSITY control value
+		 * has changed.
+		 */
+		if (ctrl->led_mode->val == V4L2_FLASH_LED_MODE_TORCH) {
+			ret = call_flash_op(v4l2_flash, torch_brightness_update,
+							led_cdev);
+			if (ret < 0)
+				return ret;
+			ctrl->torch_intensity->val =
+				v4l2_flash_led_brightness_to_intensity(
+						&config->torch_intensity,
+						led_cdev->brightness);
+		}
+		return 0;
+	case V4L2_CID_FLASH_INTENSITY:
+		ret = call_flash_op(v4l2_flash, flash_brightness_update,
+					flash);
+		if (ret < 0)
+			return ret;
+		/* no conversion is needed */
+		c->val = flash->brightness.val;
+		return 0;
+	case V4L2_CID_FLASH_INDICATOR_INTENSITY:
+		ret = call_flash_op(v4l2_flash, indicator_brightness_update,
+						flash);
+		if (ret < 0)
+			return ret;
+		/* no conversion is needed */
+		c->val = flash->indicator_brightness->val;
+		return 0;
+	case V4L2_CID_FLASH_STROBE_STATUS:
+		ret = call_flash_op(v4l2_flash, strobe_get, flash,
+							&is_strobing);
+		if (ret < 0)
+			return ret;
+		c->val = is_strobing;
+		return 0;
+	case V4L2_CID_FLASH_FAULT:
+		/* led faults map directly to V4L2 flash faults */
+		ret = call_flash_op(v4l2_flash, fault_get, flash, &c->val);
+		return ret;
+	case V4L2_CID_FLASH_STROBE_SOURCE:
+		c->val = flash->external_strobe;
+		return 0;
+	case V4L2_CID_FLASH_STROBE_PROVIDER:
+		c->val = flash->strobe_provider_id;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int v4l2_flash_s_ctrl(struct v4l2_ctrl *c)
+{
+	struct v4l2_flash *v4l2_flash = v4l2_ctrl_to_v4l2_flash(c);
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	struct v4l2_flash_ctrl *ctrl = &v4l2_flash->ctrl;
+	struct v4l2_flash_ctrl_config *config = &v4l2_flash->config;
+	enum led_brightness torch_brightness;
+	bool external_strobe;
+	int ret;
+
+	switch (c->id) {
+	case V4L2_CID_FLASH_LED_MODE:
+		switch (c->val) {
+		case V4L2_FLASH_LED_MODE_NONE:
+			call_flash_op(v4l2_flash, torch_brightness_set,
+							&flash->led_cdev, 0);
+			return call_flash_op(v4l2_flash, strobe_set, flash,
+							false);
+		case V4L2_FLASH_LED_MODE_FLASH:
+			/* Turn off torch LED */
+			call_flash_op(v4l2_flash, torch_brightness_set,
+							&flash->led_cdev, 0);
+			external_strobe = (ctrl->source->val ==
+					V4L2_FLASH_STROBE_SOURCE_EXTERNAL);
+			return call_flash_op(v4l2_flash, external_strobe_set,
+						flash, external_strobe);
+		case V4L2_FLASH_LED_MODE_TORCH:
+			/* Stop flash strobing */
+			ret = call_flash_op(v4l2_flash, strobe_set, flash,
+							false);
+			if (ret)
+				return ret;
+
+			torch_brightness =
+				v4l2_flash_intensity_to_led_brightness(
+						&config->torch_intensity,
+						ctrl->torch_intensity->val);
+			call_flash_op(v4l2_flash, torch_brightness_set,
+					&flash->led_cdev, torch_brightness);
+			return ret;
+		}
+		break;
+	case V4L2_CID_FLASH_STROBE_SOURCE:
+		external_strobe = (c->val == V4L2_FLASH_STROBE_SOURCE_EXTERNAL);
+
+		return call_flash_op(v4l2_flash, external_strobe_set, flash,
+							external_strobe);
+	case V4L2_CID_FLASH_STROBE:
+		if (ctrl->led_mode->val != V4L2_FLASH_LED_MODE_FLASH ||
+		    ctrl->source->val != V4L2_FLASH_STROBE_SOURCE_SOFTWARE)
+			return -EINVAL;
+		return call_flash_op(v4l2_flash, strobe_set, flash, true);
+	case V4L2_CID_FLASH_STROBE_STOP:
+		return call_flash_op(v4l2_flash, strobe_set, flash, false);
+	case V4L2_CID_FLASH_TIMEOUT:
+		return call_flash_op(v4l2_flash, timeout_set, flash, c->val);
+	case V4L2_CID_FLASH_INTENSITY:
+		/* no conversion is needed */
+		return call_flash_op(v4l2_flash, flash_brightness_set, flash,
+								c->val);
+	case V4L2_CID_FLASH_INDICATOR_INTENSITY:
+		/* no conversion is needed */
+		return call_flash_op(v4l2_flash, indicator_brightness_set,
+						flash, c->val);
+	case V4L2_CID_FLASH_TORCH_INTENSITY:
+		/*
+		 * If not in MODE_TORCH don't call led-class brightness_set
+		 * op, as it would result in turning the torch led on.
+		 * Instead the value is cached only and will be written
+		 * to the device upon transition to MODE_TORCH.
+		 */
+		if (ctrl->led_mode->val == V4L2_FLASH_LED_MODE_TORCH) {
+			torch_brightness =
+				v4l2_flash_intensity_to_led_brightness(
+						&config->torch_intensity,
+						ctrl->torch_intensity->val);
+			call_flash_op(v4l2_flash, torch_brightness_set,
+					&flash->led_cdev, torch_brightness);
+		}
+		return 0;
+	case V4L2_CID_FLASH_STROBE_PROVIDER:
+		flash->strobe_provider_id = c->val;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static const struct v4l2_ctrl_ops v4l2_flash_ctrl_ops = {
+	.g_volatile_ctrl = v4l2_flash_g_volatile_ctrl,
+	.s_ctrl = v4l2_flash_s_ctrl,
+};
+
+static int v4l2_flash_init_strobe_providers_menu(struct v4l2_flash *v4l2_flash)
+{
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	struct led_flash_strobe_provider *provider;
+	struct v4l2_ctrl *ctrl;
+	int i = 0;
+
+	v4l2_flash->strobe_providers_menu =
+			kzalloc(sizeof(char *) * (flash->num_strobe_providers),
+					GFP_KERNEL);
+	if (!v4l2_flash->strobe_providers_menu)
+		return -ENOMEM;
+
+	list_for_each_entry(provider, &flash->strobe_providers, list)
+		v4l2_flash->strobe_providers_menu[i++] =
+						(char *) provider->name;
+
+	ctrl = v4l2_ctrl_new_std_menu_items(
+		&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+		V4L2_CID_FLASH_STROBE_PROVIDER,
+		flash->num_strobe_providers - 1,
+		0, 0,
+		(const char * const *) v4l2_flash->strobe_providers_menu);
+
+	if (ctrl)
+		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+
+	return 0;
+}
+
+static int v4l2_flash_init_controls(struct v4l2_flash *v4l2_flash)
+
+{
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	const struct led_flash_ops *flash_ops = flash->ops;
+	struct led_classdev *led_cdev = &flash->led_cdev;
+	struct v4l2_flash_ctrl_config *config = &v4l2_flash->config;
+	struct v4l2_ctrl *ctrl;
+	struct v4l2_ctrl_config *ctrl_cfg;
+	bool has_flash = led_cdev->flags & LED_DEV_CAP_FLASH;
+	bool has_indicator = led_cdev->flags & LED_DEV_CAP_INDICATOR;
+	bool has_strobe_providers = (flash->num_strobe_providers > 1);
+	unsigned int mask;
+	int ret, max, num_ctrls;
+
+	num_ctrls = has_flash ? 5 : 2;
+	if (has_flash) {
+		if (flash_ops->flash_brightness_set)
+			++num_ctrls;
+		if (flash_ops->timeout_set)
+			++num_ctrls;
+		if (flash_ops->strobe_get)
+			++num_ctrls;
+		if (has_indicator)
+			++num_ctrls;
+		if (config->flash_faults)
+			++num_ctrls;
+		if (has_strobe_providers)
+			++num_ctrls;
+	}
+
+	v4l2_ctrl_handler_init(&v4l2_flash->hdl, num_ctrls);
+
+	mask = 1 << V4L2_FLASH_LED_MODE_NONE |
+	       1 << V4L2_FLASH_LED_MODE_TORCH;
+	if (flash)
+		mask |= 1 << V4L2_FLASH_LED_MODE_FLASH;
+
+	/* Configure FLASH_LED_MODE ctrl */
+	v4l2_flash->ctrl.led_mode = v4l2_ctrl_new_std_menu(
+			&v4l2_flash->hdl,
+			&v4l2_flash_ctrl_ops, V4L2_CID_FLASH_LED_MODE,
+			V4L2_FLASH_LED_MODE_TORCH, ~mask,
+			V4L2_FLASH_LED_MODE_NONE);
+
+	/* Configure TORCH_INTENSITY ctrl */
+	ctrl_cfg = &config->torch_intensity;
+	ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+				 V4L2_CID_FLASH_TORCH_INTENSITY,
+				 ctrl_cfg->min, ctrl_cfg->max,
+				 ctrl_cfg->step, ctrl_cfg->def);
+	if (ctrl)
+		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+	v4l2_flash->ctrl.torch_intensity = ctrl;
+
+	if (has_flash) {
+		/* Configure FLASH_STROBE_SOURCE ctrl */
+		mask = 1 << V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
+
+		if (flash->has_external_strobe) {
+			mask |= 1 << V4L2_FLASH_STROBE_SOURCE_EXTERNAL;
+			max = V4L2_FLASH_STROBE_SOURCE_EXTERNAL;
+		} else {
+			max = V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
+		}
+
+		v4l2_flash->ctrl.source = v4l2_ctrl_new_std_menu(
+					&v4l2_flash->hdl,
+					&v4l2_flash_ctrl_ops,
+					V4L2_CID_FLASH_STROBE_SOURCE,
+					max,
+					~mask,
+					V4L2_FLASH_STROBE_SOURCE_SOFTWARE);
+		if (v4l2_flash->ctrl.source)
+			v4l2_flash->ctrl.source->flags |=
+						V4L2_CTRL_FLAG_VOLATILE;
+
+		/* Configure FLASH_STROBE ctrl */
+		ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+					  V4L2_CID_FLASH_STROBE, 0, 1, 1, 0);
+
+		/* Configure FLASH_STROBE_STOP ctrl */
+		ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+					  V4L2_CID_FLASH_STROBE_STOP,
+					  0, 1, 1, 0);
+
+		/* Configure FLASH_STROBE_STATUS ctrl */
+		ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+					 V4L2_CID_FLASH_STROBE_STATUS,
+					 0, 1, 1, 1);
+
+		if (flash_ops->strobe_get)
+			if (ctrl)
+				ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE |
+					       V4L2_CTRL_FLAG_READ_ONLY;
+
+		if (flash_ops->timeout_set) {
+			/* Configure FLASH_TIMEOUT ctrl */
+			ctrl_cfg = &config->flash_timeout;
+			ctrl = v4l2_ctrl_new_std(
+					&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+					V4L2_CID_FLASH_TIMEOUT, ctrl_cfg->min,
+					ctrl_cfg->max, ctrl_cfg->step,
+					ctrl_cfg->def);
+			if (ctrl)
+				ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+		}
+
+		if (flash_ops->flash_brightness_set) {
+			/* Configure FLASH_INTENSITY ctrl */
+			ctrl_cfg = &config->flash_intensity;
+			ctrl = v4l2_ctrl_new_std(
+					&v4l2_flash->hdl,
+					&v4l2_flash_ctrl_ops,
+					V4L2_CID_FLASH_INTENSITY,
+					ctrl_cfg->min, ctrl_cfg->max,
+					ctrl_cfg->step, ctrl_cfg->def);
+			if (ctrl)
+				ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+		}
+
+		if (config->flash_faults) {
+			/* Configure FLASH_FAULT ctrl */
+			ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl,
+						 &v4l2_flash_ctrl_ops,
+						 V4L2_CID_FLASH_FAULT, 0,
+						 config->flash_faults,
+						 0, 0);
+			if (ctrl)
+				ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE |
+					       V4L2_CTRL_FLAG_READ_ONLY;
+		}
+		if (has_indicator) {
+			/* Configure FLASH_INDICATOR_INTENSITY ctrl */
+			ctrl_cfg = &config->indicator_intensity;
+			ctrl = v4l2_ctrl_new_std(
+					&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+					V4L2_CID_FLASH_INDICATOR_INTENSITY,
+					ctrl_cfg->min, ctrl_cfg->max,
+					ctrl_cfg->step, ctrl_cfg->def);
+			if (ctrl)
+				ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+		}
+
+		if (has_strobe_providers) {
+			/* Configure V4L2_CID_FLASH_STROBE_PROVIDERS ctrl */
+			ret = v4l2_flash_init_strobe_providers_menu(v4l2_flash);
+			if (ret < 0)
+				goto error_free_handler;
+		}
+	}
+
+	if (v4l2_flash->hdl.error) {
+		ret = v4l2_flash->hdl.error;
+		goto error_free_handler;
+	}
+
+	ret = v4l2_ctrl_handler_setup(&v4l2_flash->hdl);
+	if (ret < 0)
+		goto error_free_handler;
+
+	v4l2_flash->sd.ctrl_handler = &v4l2_flash->hdl;
+
+	return 0;
+
+error_free_handler:
+	v4l2_ctrl_handler_free(&v4l2_flash->hdl);
+	return ret;
+}
+
+/*
+ * V4L2 subdev internal operations
+ */
+
+static int v4l2_flash_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	struct v4l2_flash *v4l2_flash = v4l2_subdev_to_v4l2_flash(sd);
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	struct led_classdev *led_cdev = &flash->led_cdev;
+
+	mutex_lock(&led_cdev->led_lock);
+	call_flash_op(v4l2_flash, sysfs_lock, led_cdev);
+	mutex_unlock(&led_cdev->led_lock);
+
+	return 0;
+}
+
+static int v4l2_flash_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	struct v4l2_flash *v4l2_flash = v4l2_subdev_to_v4l2_flash(sd);
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	struct led_classdev *led_cdev = &flash->led_cdev;
+
+	mutex_lock(&led_cdev->led_lock);
+	call_flash_op(v4l2_flash, sysfs_unlock, led_cdev);
+	mutex_unlock(&led_cdev->led_lock);
+
+	return 0;
+}
+
+int v4l2_flash_register(struct v4l2_flash *v4l2_flash)
+{
+	struct led_classdev_flash *flash = v4l2_flash->flash;
+	struct led_classdev *led_cdev = &flash->led_cdev;
+	int ret;
+
+	if (!v4l2_dev) {
+		v4l2_dev = kzalloc(sizeof(*v4l2_dev), GFP_KERNEL);
+		if (!v4l2_dev)
+			return -ENOMEM;
+
+		strlcpy(v4l2_dev->name, "v4l2-flash-manager",
+						sizeof(v4l2_dev->name));
+		ret = v4l2_device_register(NULL, v4l2_dev);
+		if (ret < 0) {
+			dev_err(led_cdev->dev->parent,
+				 "Failed to register v4l2_device: %d\n", ret);
+			goto err_v4l2_device_register;
+		}
+	}
+
+	ret = v4l2_device_register_subdev(v4l2_dev, &v4l2_flash->sd);
+	if (ret < 0) {
+		dev_err(led_cdev->dev->parent,
+			 "Failed to register v4l2_subdev: %d\n", ret);
+		goto err_v4l2_device_register;
+	}
+
+	ret = v4l2_device_register_subdev_node(&v4l2_flash->sd, v4l2_dev);
+	if (ret < 0) {
+		dev_err(led_cdev->dev->parent,
+			 "Failed to register v4l2_subdev node: %d\n", ret);
+		goto err_register_subdev_node;
+	}
+
+	++registered_flashes;
+
+	return 0;
+
+err_register_subdev_node:
+	v4l2_device_unregister_subdev(&v4l2_flash->sd);
+err_v4l2_device_register:
+	kfree(v4l2_flash->strobe_providers_menu);
+	if (v4l2_dev && registered_flashes == 0) {
+		v4l2_device_unregister(v4l2_dev);
+		kfree(v4l2_dev);
+		v4l2_dev = NULL;
+	}
+
+	return ret;
+}
+
+static void v4l2_flash_unregister(struct v4l2_flash *v4l2_flash)
+{
+	if (registered_flashes == 0)
+		return;
+
+	v4l2_device_unregister_subdev(&v4l2_flash->sd);
+
+	--registered_flashes;
+
+	if (registered_flashes == 0) {
+		v4l2_device_unregister(v4l2_dev);
+		kfree(v4l2_dev);
+		v4l2_dev = NULL;
+	}
+}
+
+static const struct v4l2_subdev_internal_ops v4l2_flash_subdev_internal_ops = {
+	.open = v4l2_flash_open,
+	.close = v4l2_flash_close,
+};
+
+static const struct v4l2_subdev_core_ops v4l2_flash_core_ops = {
+	.queryctrl = v4l2_subdev_queryctrl,
+	.querymenu = v4l2_subdev_querymenu,
+};
+
+static const struct v4l2_subdev_ops v4l2_flash_subdev_ops = {
+	.core = &v4l2_flash_core_ops,
+};
+
+int v4l2_flash_init(struct led_classdev_flash *flash,
+		    struct v4l2_flash_ctrl_config *config,
+		    const struct v4l2_flash_ops *flash_ops,
+		    struct v4l2_flash **out_flash)
+{
+	struct v4l2_flash *v4l2_flash;
+	struct led_classdev *led_cdev = &flash->led_cdev;
+	struct v4l2_subdev *sd;
+	int ret;
+
+	if (!flash || !config || !out_flash)
+		return -EINVAL;
+
+	v4l2_flash = kzalloc(sizeof(*v4l2_flash), GFP_KERNEL);
+	if (!v4l2_flash)
+		return -ENOMEM;
+
+	sd = &v4l2_flash->sd;
+	v4l2_flash->flash = flash;
+	v4l2_flash->ops = flash_ops;
+	sd->dev = led_cdev->dev->parent;
+	v4l2_subdev_init(sd, &v4l2_flash_subdev_ops);
+	sd->internal_ops = &v4l2_flash_subdev_internal_ops;
+	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	snprintf(sd->name, sizeof(sd->name), led_cdev->name);
+
+	v4l2_flash->config = *config;
+	ret = v4l2_flash_init_controls(v4l2_flash);
+	if (ret < 0)
+		goto err_init_controls;
+
+	ret = media_entity_init(&sd->entity, 0, NULL, 0);
+	if (ret < 0)
+		goto err_init_entity;
+
+	sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV_FLASH;
+
+	ret = v4l2_flash_register(v4l2_flash);
+	if (ret < 0)
+		goto err_init_entity;
+
+	*out_flash = v4l2_flash;
+
+	return 0;
+
+err_init_entity:
+	media_entity_cleanup(&sd->entity);
+err_init_controls:
+	v4l2_ctrl_handler_free(sd->ctrl_handler);
+	kfree(v4l2_flash);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_flash_init);
+
+void v4l2_flash_release(struct v4l2_flash *v4l2_flash)
+{
+	if (!v4l2_flash)
+		return;
+
+	v4l2_flash_unregister(v4l2_flash);
+	v4l2_ctrl_handler_free(v4l2_flash->sd.ctrl_handler);
+	media_entity_cleanup(&v4l2_flash->sd.entity);
+	kfree(v4l2_flash->strobe_providers_menu);
+	kfree(v4l2_flash);
+}
+EXPORT_SYMBOL_GPL(v4l2_flash_release);
diff --git a/include/media/v4l2-flash.h b/include/media/v4l2-flash.h
new file mode 100644
index 0000000..effa46b
--- /dev/null
+++ b/include/media/v4l2-flash.h
@@ -0,0 +1,137 @@
+/*
+ * V4L2 Flash LED sub-device registration helpers.
+ *
+ *	Copyright (C) 2014 Samsung Electronics Co., Ltd
+ *	Author: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
+ *
+ * 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."
+ */
+
+#ifndef _V4L2_FLASH_H
+#define _V4L2_FLASH_H
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-dev.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-ioctl.h>
+
+struct led_classdev_flash;
+struct led_classdev;
+enum led_brightness;
+
+struct v4l2_flash_ops {
+	int (*torch_brightness_set)(struct led_classdev *led_cdev,
+					enum led_brightness brightness);
+	int (*torch_brightness_update)(struct led_classdev *led_cdev);
+	int (*flash_brightness_set)(struct led_classdev_flash *flash,
+					u32 brightness);
+	int (*flash_brightness_update)(struct led_classdev_flash *flash);
+	int (*strobe_set)(struct led_classdev_flash *flash, bool state);
+	int (*strobe_get)(struct led_classdev_flash *flash, bool *state);
+	int (*timeout_set)(struct led_classdev_flash *flash, u32 timeout);
+	int (*indicator_brightness_set)(struct led_classdev_flash *flash,
+					u32 brightness);
+	int (*indicator_brightness_update)(struct led_classdev_flash *flash);
+	int (*external_strobe_set)(struct led_classdev_flash *flash,
+					bool enable);
+	int (*fault_get)(struct led_classdev_flash *flash, u32 *fault);
+	void (*sysfs_lock)(struct led_classdev *led_cdev);
+	void (*sysfs_unlock)(struct led_classdev *led_cdev);
+};
+
+/**
+ * struct v4l2_flash_ctrl - controls that define the sub-dev's state
+ * @source:		V4L2_CID_FLASH_STROBE_SOURCE control
+ * @led_mode:		V4L2_CID_FLASH_LED_MODE control
+ * @torch_intensity:	V4L2_CID_FLASH_TORCH_INTENSITY control
+ */
+struct v4l2_flash_ctrl {
+	struct v4l2_ctrl *source;
+	struct v4l2_ctrl *led_mode;
+	struct v4l2_ctrl *torch_intensity;
+};
+
+/**
+ * struct v4l2_flash_ctrl_config - V4L2 Flash controls initialization data
+ * @torch_intensity:		V4L2_CID_FLASH_TORCH_INTENSITY constraints
+ * @flash_intensity:		V4L2_CID_FLASH_INTENSITY constraints
+ * @indicator_intensity:	V4L2_CID_FLASH_INDICATOR_INTENSITY constraints
+ * @flash_timeout:		V4L2_CID_FLASH_TIMEOUT constraints
+ * @flash_fault:		possible flash faults
+ */
+struct v4l2_flash_ctrl_config {
+	struct v4l2_ctrl_config torch_intensity;
+	struct v4l2_ctrl_config flash_intensity;
+	struct v4l2_ctrl_config indicator_intensity;
+	struct v4l2_ctrl_config flash_timeout;
+	u32 flash_faults;
+};
+
+/**
+ * struct v4l2_flash - Flash sub-device context
+ * @flash:		LED Flash Class device controlled by this sub-device
+ * @ops:		LED Flash Class device ops
+ * @sd:			V4L2 sub-device
+ * @hdl:		flash controls handler
+ * @ctrl:		state defining controls
+ * @config:		V4L2 Flash controlsrconfiguration data
+ * @software_strobe_gates: route to the software strobe signal
+ * @external_strobe_gates: route to the external strobe signal
+ * @sensors:		available external strobe sources
+ */
+struct v4l2_flash {
+	struct led_classdev_flash *flash;
+	const struct v4l2_flash_ops *ops;
+
+	struct v4l2_subdev sd;
+	struct v4l2_ctrl_handler hdl;
+	struct v4l2_flash_ctrl ctrl;
+	struct v4l2_flash_ctrl_config config;
+	char **strobe_providers_menu;
+};
+
+static inline struct v4l2_flash *v4l2_subdev_to_v4l2_flash(
+							struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct v4l2_flash, sd);
+}
+
+static inline struct v4l2_flash *v4l2_ctrl_to_v4l2_flash(struct v4l2_ctrl *c)
+{
+	return container_of(c->handler, struct v4l2_flash, hdl);
+}
+
+#ifdef CONFIG_V4L2_FLASH_LED_CLASS
+/**
+ * v4l2_flash_init - initialize V4L2 flash led sub-device
+ * @led_fdev:	the LED Flash Class device to wrap
+ * @config:	initialization data for V4L2 Flash controls
+ * @flash_ops:	V4L2 Flash device ops
+ * @out_flash:	handler to the new V4L2 Flash device
+ *
+ * Create V4L2 subdev wrapping given LED subsystem device.
+
+ * Returns: 0 on success or negative error value on failure
+ */
+int v4l2_flash_init(struct led_classdev_flash *led_fdev,
+		    struct v4l2_flash_ctrl_config *config,
+		    const struct v4l2_flash_ops *flash_ops,
+		    struct v4l2_flash **out_flash);
+
+/**
+ * v4l2_flash_release - release V4L2 Flash sub-device
+ * @flash: the V4L2 Flash device to release
+ *
+ * Release V4L2 flash led subdev.
+ */
+void v4l2_flash_release(struct v4l2_flash *v4l2_flash);
+
+#else
+#define v4l2_flash_init(led_cdev, config, flash_ops, out_flash) (0)
+#define v4l2_flash_release(v4l2_flash)
+#endif /* CONFIG_V4L2_FLASH_LED_CLASS */
+
+#endif /* _V4L2_FLASH_H */
-- 
1.7.9.5

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