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.anaszew...@samsung.com>
Acked-by: Kyungmin Park <kyungmin.p...@samsung.com>
Cc: Sakari Ailus <sakari.ai...@iki.fi>
Cc: Hans Verkuil <hans.verk...@cisco.com>
Cc: Bryan Wu <coolo...@gmail.com>
Cc: Richard Purdie <rpur...@rpsys.net>
---
 drivers/leds/led-class-flash.c       |   25 ++
 drivers/media/v4l2-core/Kconfig      |   11 +
 drivers/media/v4l2-core/Makefile     |    2 +
 drivers/media/v4l2-core/v4l2-flash.c |  577 ++++++++++++++++++++++++++++++++++
 include/linux/led-class-flash.h      |   11 +
 include/media/v4l2-flash.h           |  121 +++++++
 6 files changed, 747 insertions(+)
 create mode 100644 drivers/media/v4l2-core/v4l2-flash.c
 create mode 100644 include/media/v4l2-flash.h

diff --git a/drivers/leds/led-class-flash.c b/drivers/leds/led-class-flash.c
index 4ff99a9..a73f5fd 100644
--- a/drivers/leds/led-class-flash.c
+++ b/drivers/leds/led-class-flash.c
@@ -16,6 +16,7 @@
 #include <linux/led-flash-manager.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <media/v4l2-flash.h>
 #include "leds.h"
 
 #define has_flash_op(flash, op)                                \
@@ -355,6 +356,30 @@ static void led_flash_resume(struct led_classdev *led_cdev)
                                flash->indicator_brightness->val);
 }
 
+#ifdef CONFIG_V4L2_FLASH_LED_CLASS
+const struct v4l2_flash_ops led_flash_v4l2_ops = {
+       .torch_brightness_set = led_set_torch_brightness,
+       .torch_brightness_update = led_update_brightness,
+       .flash_brightness_set = led_set_flash_brightness,
+       .flash_brightness_update = led_update_flash_brightness,
+       .indicator_brightness_set = led_set_indicator_brightness,
+       .indicator_brightness_update = led_update_indicator_brightness,
+       .strobe_set = led_set_flash_strobe,
+       .strobe_get = led_get_flash_strobe,
+       .timeout_set = led_set_flash_timeout,
+       .external_strobe_set = led_set_external_strobe,
+       .fault_get = led_get_flash_fault,
+       .sysfs_lock = led_sysfs_lock,
+       .sysfs_unlock = led_sysfs_unlock,
+};
+
+const struct v4l2_flash_ops *led_get_v4l2_flash_ops(void)
+{
+       return &led_flash_v4l2_ops;
+}
+EXPORT_SYMBOL_GPL(led_get_v4l2_flash_ops);
+#endif
+
 static void led_flash_remove_sysfs_groups(struct led_classdev_flash *flash)
 {
        struct led_classdev *led_cdev = &flash->led_cdev;
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..51e7238
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-flash.c
@@ -0,0 +1,577 @@
+/*
+ * V4L2 Flash LED sub-device registration helpers.
+ *
+ *     Copyright (C) 2014 Samsung Electronics Co., Ltd
+ *     Author: Jacek Anaszewski <j.anaszew...@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/led-class-flash.h>
+#include <linux/mutex.h>
+#include <linux/of_led_flash_manager.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <media/v4l2-flash.h>
+
+#define call_flash_op(v4l2_flash, op, args...)                 \
+               (v4l2_flash->ops->op  ?                         \
+                       v4l2_flash->ops->op(args) :             \
+                       -EINVAL)
+
+enum ctrl_init_data_id {
+       LED_MODE,
+       TORCH_INTENSITY,
+       STROBE_SOURCE,
+       FLASH_STROBE,
+       STROBE_STOP,
+       STROBE_STATUS,
+       FLASH_TIMEOUT,
+       FLASH_INTENSITY,
+       INDICATOR_INTENSITY,
+       FLASH_FAULT,
+       NUM_FLASH_CTRLS,
+};
+
+struct v4l2_flash_ctrl_data {
+       struct v4l2_ctrl_config config;
+       bool supported;
+};
+
+static inline enum led_brightness v4l2_flash_intensity_to_led_brightness(
+                                       struct v4l2_ctrl *ctrl,
+                                       s32 intensity)
+{
+       s64 __intensity = intensity - ctrl->minimum;
+
+       do_div(__intensity, ctrl->step);
+
+       return __intensity + 1;
+}
+
+static inline s32 v4l2_flash_led_brightness_to_intensity(
+                                       struct v4l2_ctrl *ctrl,
+                                       enum led_brightness brightness)
+{
+       return ((brightness - 1) * ctrl->step) + ctrl->minimum;
+}
+
+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_ctrl **ctrls = v4l2_flash->ctrls;
+       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 (ctrls[LED_MODE]->val == V4L2_FLASH_LED_MODE_TORCH) {
+                       ret = call_flash_op(v4l2_flash, torch_brightness_update,
+                                                       led_cdev);
+                       if (ret < 0)
+                               return ret;
+                       ctrls[TORCH_INTENSITY]->val =
+                               v4l2_flash_led_brightness_to_intensity(
+                                               ctrls[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_ctrl **ctrls = v4l2_flash->ctrls;
+       enum led_brightness torch_brightness;
+       bool external_strobe;
+       int ret = 0;
+
+       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 = (ctrls[STROBE_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(
+                                               ctrls[TORCH_INTENSITY],
+                                               ctrls[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 (ctrls[LED_MODE]->val != V4L2_FLASH_LED_MODE_FLASH ||
+                   ctrls[STROBE_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:
+               if (ctrls[LED_MODE]->val != V4L2_FLASH_LED_MODE_FLASH ||
+                   flash->external_strobe)
+                       return -EINVAL;
+               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 (ctrls[LED_MODE]->val == V4L2_FLASH_LED_MODE_TORCH) {
+                       torch_brightness =
+                               v4l2_flash_intensity_to_led_brightness(
+                                                       ctrls[TORCH_INTENSITY],
+                                                       c->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;
+               if (ctrls[LED_MODE]->val == V4L2_FLASH_LED_MODE_FLASH &&
+                   ctrls[STROBE_SOURCE]->val ==
+                                       V4L2_FLASH_STROBE_SOURCE_EXTERNAL)
+                       ret = call_flash_op(v4l2_flash, external_strobe_set,
+                                               flash, true);
+               return ret;
+       }
+
+       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 =
+                       kcalloc((flash->num_strobe_providers), sizeof(char *),
+                                       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 void fill_ctrl_init_data(struct v4l2_flash *v4l2_flash,
+                         struct v4l2_flash_ctrl_config *flash_cfg,
+                         struct v4l2_flash_ctrl_data *ctrl_init_data)
+{
+       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_ctrl_config *ctrl_cfg;
+       u32 mask;
+       s64 max;
+
+       /* Init FLASH_LED_MODE ctrl data */
+       mask = 1 << V4L2_FLASH_LED_MODE_NONE |
+              1 << V4L2_FLASH_LED_MODE_TORCH;
+       if (flash)
+               mask |= 1 << V4L2_FLASH_LED_MODE_FLASH;
+
+       ctrl_init_data[LED_MODE].supported = true;
+       ctrl_cfg = &ctrl_init_data[LED_MODE].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_LED_MODE;
+       ctrl_cfg->max = V4L2_FLASH_LED_MODE_TORCH;
+       ctrl_cfg->menu_skip_mask = ~mask;
+       ctrl_cfg->def = V4L2_FLASH_LED_MODE_NONE;
+       ctrl_cfg->flags = 0;
+
+       /* Init TORCH_INTENSITY ctrl data */
+       ctrl_init_data[TORCH_INTENSITY].supported = true;
+       ctrl_init_data[TORCH_INTENSITY].config = flash_cfg->torch_intensity;
+       ctrl_cfg = &ctrl_init_data[TORCH_INTENSITY].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_TORCH_INTENSITY;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE;
+
+       if (!(led_cdev->flags & LED_DEV_CAP_FLASH))
+               return;
+
+       /* Init FLASH_STROBE_SOURCE ctrl data */
+       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;
+       }
+
+       ctrl_init_data[STROBE_SOURCE].supported = true;
+       ctrl_cfg = &ctrl_init_data[STROBE_SOURCE].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_STROBE_SOURCE;
+       ctrl_cfg->max = max;
+       ctrl_cfg->menu_skip_mask = ~mask;
+       ctrl_cfg->def = V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE;
+
+       /* Init FLASH_STROBE ctrl data */
+       ctrl_init_data[FLASH_STROBE].supported = true;
+       ctrl_cfg = &ctrl_init_data[FLASH_STROBE].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_STROBE;
+       ctrl_cfg->min = 0;
+       ctrl_cfg->max = 1;
+       ctrl_cfg->step = 1;
+       ctrl_cfg->def = 0;
+       ctrl_cfg->flags = 0;
+
+       /* Init STROBE_STOP ctrl data */
+       ctrl_init_data[STROBE_STOP].supported = true;
+       ctrl_cfg = &ctrl_init_data[STROBE_STOP].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_STROBE_STOP;
+       ctrl_cfg->min = 0;
+       ctrl_cfg->max = 1;
+       ctrl_cfg->step = 1;
+       ctrl_cfg->def = 0;
+       ctrl_cfg->flags = 0;
+
+       /* Init STROBE_STATUS ctrl data */
+       ctrl_init_data[STROBE_STATUS].supported = !!flash_ops->strobe_get;
+       ctrl_cfg = &ctrl_init_data[STROBE_STATUS].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_STROBE_STATUS;
+       ctrl_cfg->min = 0;
+       ctrl_cfg->max = 1;
+       ctrl_cfg->step = 1;
+       ctrl_cfg->def = 1;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE |
+                          V4L2_CTRL_FLAG_READ_ONLY;
+
+       /* Init FLASH_TIMEOUT ctrl data */
+       ctrl_init_data[FLASH_TIMEOUT].supported = !!flash_ops->timeout_set;
+       ctrl_init_data[FLASH_TIMEOUT].config = flash_cfg->flash_timeout;
+       ctrl_cfg = &ctrl_init_data[FLASH_TIMEOUT].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_TIMEOUT;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE;
+
+       /* Init FLASH_INTENSITY ctrl data */
+       ctrl_init_data[FLASH_INTENSITY].supported =
+                                       !!flash_ops->flash_brightness_set;
+       ctrl_init_data[FLASH_INTENSITY].config = flash_cfg->flash_intensity;
+       ctrl_cfg = &ctrl_init_data[FLASH_INTENSITY].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_INTENSITY;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE;
+
+       /* Init INDICATOR_INTENSITY ctrl data */
+       ctrl_init_data[INDICATOR_INTENSITY].supported =
+                                       led_cdev->flags & LED_DEV_CAP_INDICATOR;
+       ctrl_init_data[INDICATOR_INTENSITY].config = flash_cfg->flash_intensity;
+       ctrl_cfg = &ctrl_init_data[INDICATOR_INTENSITY].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_INDICATOR_INTENSITY;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE;
+
+       /* Init FLASH_FAULT ctrl data */
+       ctrl_init_data[FLASH_FAULT].supported = !!flash_cfg->flash_faults;
+       ctrl_cfg = &ctrl_init_data[FLASH_FAULT].config;
+       ctrl_cfg->id = V4L2_CID_FLASH_FAULT;
+       ctrl_cfg->min = 0;
+       ctrl_cfg->max = flash_cfg->flash_faults;
+       ctrl_cfg->step = 0;
+       ctrl_cfg->def = 0;
+       ctrl_cfg->flags = V4L2_CTRL_FLAG_VOLATILE | V4L2_CTRL_FLAG_READ_ONLY;
+}
+
+static int v4l2_flash_init_controls(struct v4l2_flash *v4l2_flash,
+                               struct v4l2_flash_ctrl_config *flash_cfg)
+
+{
+       struct led_classdev_flash *flash = v4l2_flash->flash;
+       bool has_strobe_providers = (flash->num_strobe_providers > 1);
+       struct v4l2_flash_ctrl_data *ctrl_init_data;
+       struct v4l2_ctrl *ctrl;
+       struct v4l2_ctrl_config *ctrl_cfg;
+       int i, ret, num_ctrls = 0;
+
+       /* allocate memory dynamically so as not to exceed stack frame size */
+       ctrl_init_data = kcalloc(NUM_FLASH_CTRLS, sizeof(*ctrl_init_data),
+                                       GFP_KERNEL);
+       if (!ctrl_init_data)
+               return -ENOMEM;
+
+       memset(ctrl_init_data, 0, sizeof(*ctrl_init_data));
+
+       fill_ctrl_init_data(v4l2_flash, flash_cfg, ctrl_init_data);
+
+       for (i = 0; i < NUM_FLASH_CTRLS; ++i)
+               if (ctrl_init_data[i].supported)
+                       ++num_ctrls;
+
+       if (has_strobe_providers)
+               ++num_ctrls;
+
+       v4l2_ctrl_handler_init(&v4l2_flash->hdl, num_ctrls);
+
+       for (i = 0; i < NUM_FLASH_CTRLS; ++i) {
+               ctrl_cfg = &ctrl_init_data[i].config;
+               if (!ctrl_init_data[i].supported)
+                       continue;
+
+               if (ctrl_cfg->id == V4L2_CID_FLASH_LED_MODE ||
+                   ctrl_cfg->id == V4L2_CID_FLASH_STROBE_SOURCE)
+                       ctrl = v4l2_ctrl_new_std_menu(&v4l2_flash->hdl,
+                                               &v4l2_flash_ctrl_ops,
+                                               ctrl_cfg->id,
+                                               ctrl_cfg->max,
+                                               ctrl_cfg->menu_skip_mask,
+                                               ctrl_cfg->def);
+               else
+                       ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl,
+                                               &v4l2_flash_ctrl_ops,
+                                               ctrl_cfg->id,
+                                               ctrl_cfg->min,
+                                               ctrl_cfg->max,
+                                               ctrl_cfg->step,
+                                               ctrl_cfg->def);
+
+               if (ctrl)
+                       ctrl->flags |= ctrl_cfg->flags;
+
+               if (i <= STROBE_SOURCE)
+                       v4l2_flash->ctrls[i] = ctrl;
+       }
+
+       kfree(ctrl_init_data);
+
+       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;
+       }
+
+       v4l2_ctrl_handler_setup(&v4l2_flash->hdl);
+
+       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;
+       int ret = 0;
+
+       mutex_lock(&led_cdev->led_lock);
+
+       if (!v4l2_fh_is_singular(&fh->vfh)) {
+               ret = -EBUSY;
+               goto unlock;
+       }
+
+       call_flash_op(v4l2_flash, sysfs_lock, led_cdev);
+
+unlock:
+       mutex_unlock(&led_cdev->led_lock);
+       return ret;
+}
+
+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;
+}
+
+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,
+};
+
+struct v4l2_flash *v4l2_flash_init(struct led_classdev_flash *flash,
+                                  struct v4l2_flash_ctrl_config *config,
+                                  const struct v4l2_flash_ops *flash_ops)
+{
+       struct v4l2_flash *v4l2_flash;
+       struct led_classdev *led_cdev = &flash->led_cdev;
+       struct v4l2_subdev *sd;
+       int ret;
+
+       if (!flash || !config)
+               return ERR_PTR(-EINVAL);
+
+       v4l2_flash = kzalloc(sizeof(*v4l2_flash), GFP_KERNEL);
+       if (!v4l2_flash)
+               return ERR_PTR(-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);
+
+       ret = v4l2_flash_init_controls(v4l2_flash, config);
+       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_async_register_subdev(sd);
+       if (ret < 0)
+               goto err_init_entity;
+
+       return v4l2_flash;
+
+err_init_entity:
+       media_entity_cleanup(&sd->entity);
+err_init_controls:
+       v4l2_ctrl_handler_free(sd->ctrl_handler);
+       kfree(v4l2_flash);
+
+       return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(v4l2_flash_init);
+
+void v4l2_flash_release(struct v4l2_flash *v4l2_flash)
+{
+       struct v4l2_subdev *sd = &v4l2_flash->sd;
+
+       if (!v4l2_flash)
+               return;
+
+       v4l2_async_unregister_subdev(sd);
+       media_entity_cleanup(&sd->entity);
+       v4l2_ctrl_handler_free(sd->ctrl_handler);
+       kfree(v4l2_flash->strobe_providers_menu);
+       kfree(v4l2_flash);
+}
+EXPORT_SYMBOL_GPL(v4l2_flash_release);
diff --git a/include/linux/led-class-flash.h b/include/linux/led-class-flash.h
index a882263..40bc8ad 100644
--- a/include/linux/led-class-flash.h
+++ b/include/linux/led-class-flash.h
@@ -14,6 +14,7 @@
 
 #include <linux/leds.h>
 
+struct v4l2_flash_ops;
 struct led_classdev_flash;
 struct device_node;
 
@@ -269,5 +270,15 @@ extern int led_set_indicator_brightness(struct 
led_classdev_flash *flash,
  */
 extern int led_update_indicator_brightness(struct led_classdev_flash *flash);
 
+#ifdef CONFIG_V4L2_FLASH_LED_CLASS
+/**
+ * led_get_v4l2_flash_ops - get ops for controlling LED Flash Class
+                           device with use of V4L2 Flash controls
+ * Returns: v4l2_flash_ops
+ */
+const struct v4l2_flash_ops *led_get_v4l2_flash_ops(void);
+#else
+#define led_get_v4l2_flash_ops() (0)
+#endif
 
 #endif /* __LINUX_FLASH_LEDS_H_INCLUDED */
diff --git a/include/media/v4l2-flash.h b/include/media/v4l2-flash.h
new file mode 100644
index 0000000..6612467
--- /dev/null
+++ b/include/media/v4l2-flash.h
@@ -0,0 +1,121 @@
+/*
+ * V4L2 Flash LED sub-device registration helpers.
+ *
+ *     Copyright (C) 2014 Samsung Electronics Co., Ltd
+ *     Author: Jacek Anaszewski <j.anaszew...@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."
+ */
+
+#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_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
+ * @ctrls:             state defining controls
+ * @strobe_providers_menu: 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_ctrl *ctrls[3];
+       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
+ *
+ * Create V4L2 subdev wrapping given LED subsystem device.
+
+ * Returns: A valid pointer, or, when an error occurs, the return
+ * value is encoded using ERR_PTR(). Use IS_ERR() to check and
+ * PTR_ERR() to obtain the numeric return value.
+ */
+struct v4l2_flash *v4l2_flash_init(struct led_classdev_flash *led_fdev,
+                                  struct v4l2_flash_ctrl_config *config,
+                                  const struct v4l2_flash_ops *flash_ops);
+
+/**
+ * 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) (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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