[media] v4l2-ctrls.h: fully document the header file (8ec4bee7) · Commits · e / devices / android_kernel_fairphone_FP3

include/media/v4l2-ctrls.h

+279 −86

Original line number	Diff line number	Diff line
		/*
		V4L2 controls support header.

		Copyright (C) 2010 Hans Verkuil <hverkuil@xs4all.nl>

		This program is free software; you can redistribute it and/or modify
		it under the terms of the GNU General Public License as published by
		the Free Software Foundation; either version 2 of the License, or
		(at your option) any later version.

		This program is distributed in the hope that it will be useful,
		but WITHOUT ANY WARRANTY; without even the implied warranty of
		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		GNU General Public License for more details.

		You should have received a copy of the GNU General Public License
		along with this program; if not, write to the Free Software
		Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		* V4L2 controls support header.
		*
		* Copyright (C) 2010 Hans Verkuil <hverkuil@xs4all.nl>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*/

		#ifndef _V4L2_CTRLS_H
		@@ -58,6 +54,7 @@ union v4l2_ctrl_ptr {

		/**
		* struct v4l2_ctrl_ops - The control operations that the driver has to provide.
		*
		* @g_volatile_ctrl: Get a new value for this control. Generally only relevant
		* for volatile (and usually read-only) controls such as a control
		* that returns the current signal strength which changes
		@@ -82,7 +79,8 @@ struct v4l2_ctrl_ops {
		* @equal: return true if both values are equal.
		* @init: initialize the value.
		* @log: log the value.
		* @validate: validate the value. Return 0 on success and a negative value otherwise.
		* @validate: validate the value. Return 0 on success and a negative value
		* otherwise.
		*/
		struct v4l2_ctrl_type_ops {
		bool (equal)(const struct v4l2_ctrl ctrl, u32 idx,
		@@ -99,6 +97,7 @@ typedef void (v4l2_ctrl_notify_fnc)(struct v4l2_ctrl ctrl, void *priv);

		/**
		* struct v4l2_ctrl - The control structure.
		*
		* @node: The list node.
		* @ev_subs: The list of control event subscriptions.
		* @handler: The handler that owns the control.
		@@ -106,7 +105,7 @@ typedef void (v4l2_ctrl_notify_fnc)(struct v4l2_ctrl ctrl, void *priv);
		* @ncontrols: Number of controls in cluster array.
		* @done: Internal flag: set for each processed control.
		* @is_new: Set when the user specified a new value for this control. It
		* is also set when called from v4l2_ctrl_handler_setup. Drivers
		* is also set when called from v4l2_ctrl_handler_setup(). Drivers
		* should never set this flag.
		* @has_changed: Set when the current value differs from the new value. Drivers
		* should never use this flag.
		@@ -119,9 +118,10 @@ typedef void (v4l2_ctrl_notify_fnc)(struct v4l2_ctrl ctrl, void *priv);
		* set this flag directly.
		* @is_int: If set, then this control has a simple integer value (i.e. it
		* uses ctrl->val).
		* @is_string: If set, then this control has type V4L2_CTRL_TYPE_STRING.
		* @is_ptr: If set, then this control is an array and/or has type >= V4L2_CTRL_COMPOUND_TYPES
		* and/or has type V4L2_CTRL_TYPE_STRING. In other words, struct
		* @is_string: If set, then this control has type %V4L2_CTRL_TYPE_STRING.
		* @is_ptr: If set, then this control is an array and/or has type >=
		* %V4L2_CTRL_COMPOUND_TYPES
		* and/or has type %V4L2_CTRL_TYPE_STRING. In other words, &struct
		* v4l2_ext_control uses field p to point to the data.
		* @is_array: If set, then this control contains an N-dimensional array.
		* @has_volatiles: If set, then one or more members of the cluster are volatile.
		@@ -177,7 +177,8 @@ struct v4l2_ctrl {
		struct list_head ev_subs;
		struct v4l2_ctrl_handler *handler;
		struct v4l2_ctrl **cluster;
		unsigned ncontrols;
		unsigned int ncontrols;

		unsigned int done:1;

		unsigned int is_new:1;
		@@ -223,10 +224,12 @@ struct v4l2_ctrl {

		/**
		* struct v4l2_ctrl_ref - The control reference.
		*
		* @node: List node for the sorted list.
		* @next: Single-link list node for the hash.
		* @ctrl: The actual control information.
		* @helper: Pointer to helper struct. Used internally in prepare_ext_ctrls().
		* @helper: Pointer to helper struct. Used internally in
		* prepare_ext_ctrls().
		*
		* Each control handler has a list of these refs. The list_head is used to
		* keep a sorted-by-control-ID list of all controls, while the next pointer
		@@ -243,6 +246,7 @@ struct v4l2_ctrl_ref {
		* struct v4l2_ctrl_handler - The control handler keeps track of all the
		* controls: both the controls owned by the handler and those inherited
		* from other handlers.
		*
		* @_lock: Default for "lock".
		* @lock: Lock to control access to this handler and its controls.
		* May be replaced by the user right after init.
		@@ -252,7 +256,8 @@ struct v4l2_ctrl_ref {
		* control is needed multiple times, so this is a simple
		* optimization.
		* @buckets: Buckets for the hashing. Allows for quick control lookup.
		* @notify: A notify callback that is called whenever the control changes value.
		* @notify: A notify callback that is called whenever the control changes
		* value.
		* Note that the handler's lock is held when the notify function
		* is called!
		* @notify_priv: Passed as argument to the v4l2_ctrl notify callback.
		@@ -274,6 +279,7 @@ struct v4l2_ctrl_handler {

		/**
		* struct v4l2_ctrl_config - Control configuration structure.
		*
		* @ops: The control ops.
		* @type_ops: The control type ops. Only needed for compound controls.
		* @id: The control ID.
		@@ -320,17 +326,28 @@ struct v4l2_ctrl_config {
		unsigned int is_private:1;
		};

		/*
		* v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
		/**
		* v4l2_ctrl_fill - Fill in the control fields based on the control ID.
		*
		* @id: ID of the control
		* @name: name of the control
		* @type: type of the control
		* @min: minimum value for the control
		* @max: maximum value for the control
		* @step: control step
		* @def: default value for the control
		* @flags: flags to be used on the control
		*
		* This works for all standard V4L2 controls.
		* For non-standard controls it will only fill in the given arguments
		* and @name will be NULL.
		* and @name will be %NULL.
		*
		* This function will overwrite the contents of @name, @type and @flags.
		* The contents of @min, @max, @step and @def may be modified depending on
		* the type.
		*
		* .. note::
		*
		* Do not use in drivers! It is used internally for backwards compatibility
		* control handling only. Once all drivers are converted to use the new
		* control framework this function will no longer be exported.
		@@ -359,7 +376,7 @@ void v4l2_ctrl_fill(u32 id, const char *name, enum v4l2_ctrl_type type,
		* macro that hides the @key and @name arguments.
		*/
		int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
		unsigned nr_of_controls_hint,
		unsigned int nr_of_controls_hint,
		struct lock_class_key key, const char name);

		#ifdef CONFIG_LOCKDEP
		@@ -437,6 +454,7 @@ void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
		/**
		* v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
		* control.
		*
		* @hdl: The control handler.
		* @cfg: The control's configuration data.
		* @priv: The control's driver-specific private data.
		@@ -445,10 +463,13 @@ void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
		* and @hdl->error is set to the error code (if it wasn't set already).
		*/
		struct v4l2_ctrl v4l2_ctrl_new_custom(struct v4l2_ctrl_handler hdl,
		const struct v4l2_ctrl_config cfg, void priv);
		const struct v4l2_ctrl_config *cfg,
		void *priv);

		/**
		* v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
		* v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu
		* control.
		*
		* @hdl: The control handler.
		* @ops: The control ops.
		* @id: The control ID.
		@@ -467,10 +488,13 @@ struct v4l2_ctrl v4l2_ctrl_new_custom(struct v4l2_ctrl_handler hdl,
		*/
		struct v4l2_ctrl v4l2_ctrl_new_std(struct v4l2_ctrl_handler hdl,
		const struct v4l2_ctrl_ops *ops,
		u32 id, s64 min, s64 max, u64 step, s64 def);
		u32 id, s64 min, s64 max, u64 step,
		s64 def);

		/**
		* v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
		* v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2
		* menu control.
		*
		* @hdl: The control handler.
		* @ops: The control ops.
		* @id: The control ID.
		@@ -495,6 +519,7 @@ struct v4l2_ctrl v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler hdl,
		/**
		* v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control
		* with driver specific menu.
		*
		* @hdl: The control handler.
		* @ops: The control ops.
		* @id: The control ID.
		@@ -513,11 +538,14 @@ struct v4l2_ctrl v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler hdl,
		*
		*/
		struct v4l2_ctrl v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler hdl,
		const struct v4l2_ctrl_ops *ops, u32 id, u8 max,
		u64 mask, u8 def, const char * const *qmenu);
		const struct v4l2_ctrl_ops *ops,
		u32 id, u8 max,
		u64 mask, u8 def,
		const char * const *qmenu);

		/**
		* v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
		*
		* @hdl: The control handler.
		* @ops: The control ops.
		* @id: The control ID.
		@@ -528,17 +556,20 @@ struct v4l2_ctrl v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler hdl,
		* Same as v4l2_ctrl_new_std_menu(), but @mask is set to 0 and it additionaly
		* takes as an argument an array of integers determining the menu items.
		*
		* If @id refers to a non-integer-menu control, then this function will return NULL.
		* If @id refers to a non-integer-menu control, then this function will
		* return %NULL.
		*/
		struct v4l2_ctrl v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler hdl,
		const struct v4l2_ctrl_ops *ops,
		u32 id, u8 max, u8 def, const s64 *qmenu_int);
		u32 id, u8 max, u8 def,
		const s64 *qmenu_int);

		typedef bool (v4l2_ctrl_filter)(const struct v4l2_ctrl ctrl);

		/**
		* v4l2_ctrl_add_handler() - Add all controls from handler @add to
		* handler @hdl.
		*
		* @hdl: The control handler.
		* @add: The control handler whose controls you want to add to
		* the @hdl control handler.
		@@ -556,6 +587,7 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,

		/**
		* v4l2_ctrl_radio_filter() - Standard filter for radio controls.
		*
		* @ctrl: The control that is filtered.
		*
		* This will return true for any controls that are valid for radio device
		@@ -567,16 +599,19 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
		bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);

		/**
		* v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
		* v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging
		* to that cluster.
		*
		* @ncontrols: The number of controls in this cluster.
		* @controls: The cluster control array of size @ncontrols.
		*/
		void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
		void v4l2_ctrl_cluster(unsigned int ncontrols, struct v4l2_ctrl **controls);


		/**
		* v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
		* that cluster and set it up for autofoo/foo-type handling.
		* v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging
		* to that cluster and set it up for autofoo/foo-type handling.
		*
		* @ncontrols: The number of controls in this cluster.
		* @controls: The cluster control array of size @ncontrols. The first control
		* must be the 'auto' control (e.g. autogain, autoexposure, etc.)
		@@ -604,12 +639,14 @@ void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
		* on the autofoo control and V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
		* if autofoo is in auto mode.
		*/
		void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
		void v4l2_ctrl_auto_cluster(unsigned int ncontrols,
		struct v4l2_ctrl **controls,
		u8 manual_val, bool set_volatile);


		/**
		* v4l2_ctrl_find() - Find a control with the given ID.
		*
		* @hdl: The control handler.
		* @id: The control ID to find.
		*
		@@ -634,6 +671,7 @@ void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);

		/**
		* v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
		*
		* @ctrl: The control to (de)activate.
		* @grabbed: True if the control should become grabbed.
		*
		@@ -673,6 +711,7 @@ int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,

		/**
		* v4l2_ctrl_modify_range() - Update the range of a control.
		*
		* @ctrl: The control to update.
		* @min: The control's minimum value.
		* @max: The control's maximum value.
		@@ -703,6 +742,7 @@ static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,

		/**
		* v4l2_ctrl_notify() - Function to set a notify callback for a control.
		*
		* @ctrl: The control.
		* @notify: The callback function.
		* @priv: The callback private handle, passed as argument to the callback.
		@@ -714,10 +754,12 @@ static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
		* There can be only one notify. If another already exists, then a WARN_ON
		* will be issued and the function will do nothing.
		*/
		void v4l2_ctrl_notify(struct v4l2_ctrl ctrl, v4l2_ctrl_notify_fnc notify, void priv);
		void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify,
		void *priv);

		/**
		* v4l2_ctrl_get_name() - Get the name of the control
		*
		* @id: The control ID.
		*
		* This function returns the name of the given control ID or NULL if it isn't
		@@ -727,6 +769,7 @@ const char *v4l2_ctrl_get_name(u32 id);

		/**
		* v4l2_ctrl_get_menu() - Get the menu string array of the control
		*
		* @id: The control ID.
		*
		* This function returns the NULL-terminated menu string array name of the
		@@ -736,6 +779,7 @@ const char * const *v4l2_ctrl_get_menu(u32 id);

		/**
		* v4l2_ctrl_get_int_menu() - Get the integer menu array of the control
		*
		* @id: The control ID.
		* @len: The size of the integer array.
		*
		@@ -745,7 +789,9 @@ const char * const *v4l2_ctrl_get_menu(u32 id);
		const s64 v4l2_ctrl_get_int_menu(u32 id, u32 len);

		/**
		* v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
		* v4l2_ctrl_g_ctrl() - Helper function to get the control's value from
		* within a driver.
		*
		* @ctrl: The control.
		*
		* This returns the control's value safely by going through the control
		@@ -758,8 +804,9 @@ s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);

		/**
		* __v4l2_ctrl_s_ctrl() - Unlocked variant of v4l2_ctrl_s_ctrl().
		*
		* @ctrl: The control.
		* @val: The new value.
		* @val: TheControls name new value.
		*
		* This sets the control's new value safely by going through the control
		* framework. This function assumes the control's handler is already locked,
		@@ -769,7 +816,9 @@ s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
		*/
		int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);

		/** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
		/**
		* v4l2_ctrl_s_ctrl() - Helper function to set the control's value from
		* within a driver.
		* @ctrl: The control.
		* @val: The new value.
		*
		@@ -793,6 +842,7 @@ static inline int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
		/**
		* v4l2_ctrl_g_ctrl_int64() - Helper function to get a 64-bit control's value
		* from within a driver.
		*
		* @ctrl: The control.
		*
		* This returns the control's value safely by going through the control
		@@ -817,7 +867,8 @@ s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl);
		*/
		int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val);

		/** v4l2_ctrl_s_ctrl_int64() - Helper function to set a 64-bit control's value
		/**
		* v4l2_ctrl_s_ctrl_int64() - Helper function to set a 64-bit control's value
		* from within a driver.
		*
		* @ctrl: The control.
		@@ -840,7 +891,8 @@ static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
		return rval;
		}

		/** __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string().
		/**
		* __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string().
		*
		* @ctrl: The control.
		* @s: The new string.
		@@ -853,12 +905,13 @@ static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
		*/
		int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl ctrl, const char s);

		/** v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value
		/**
		* v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value
		* from within a driver.
		*
		* @ctrl: The control.
		* @s: The new string.
		*
		*Controls name
		* This sets the control's new string safely by going through the control
		* framework. This function will lock the control's handler, so it cannot be
		* used from within the &v4l2_ctrl_ops functions.
		@@ -878,39 +931,179 @@ static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl ctrl, const char s)

		/* Internal helper functions that deal with control events. */
		extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;

		/**
		* v4l2_ctrl_replace - Function to be used as a callback to
		* &struct v4l2_subscribed_event_ops replace\(\)
		*
		* @old: pointer to :ref:`struct v4l2_event <v4l2-event>` with the reported
		* event;
		* @new: pointer to :ref:`struct v4l2_event <v4l2-event>` with the modified
		* event;
		*/
		void v4l2_ctrl_replace(struct v4l2_event old, const struct v4l2_event new);

		/**
		* v4l2_ctrl_merge - Function to be used as a callback to
		* &struct v4l2_subscribed_event_ops merge(\)
		*
		* @old: pointer to :ref:`struct v4l2_event <v4l2-event>` with the reported
		* event;
		* @new: pointer to :ref:`struct v4l2_event <v4l2-event>` with the merged
		* event;
		*/
		void v4l2_ctrl_merge(const struct v4l2_event old, struct v4l2_event new);

		/* Can be used as a vidioc_log_status function that just dumps all controls
		associated with the filehandle. */
		/**
		* v4l2_ctrl_log_status - helper function to implement %VIDIOC_LOG_STATUS ioctl
		*
		* @file: pointer to struct file
		* @fh: unused. Kept just to be compatible to the arguments expected by
		* &struct v4l2_ioctl_ops.vidioc_log_status.
		*
		* Can be used as a vidioc_log_status function that just dumps all controls
		* associated with the filehandle.
		*/
		int v4l2_ctrl_log_status(struct file file, void fh);

		/* Can be used as a vidioc_subscribe_event function that just subscribes
		control events. */
		/**
		* v4l2_ctrl_subscribe_event - Subscribes to an event
		*
		*
		* @fh: pointer to struct v4l2_fh
		* @sub: pointer to &struct v4l2_event_subscription
		*
		* Can be used as a vidioc_subscribe_event function that just subscribes
		* control events.
		*/
		int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
		const struct v4l2_event_subscription *sub);

		/* Can be used as a poll function that just polls for control events. */
		/**
		* v4l2_ctrl_poll - function to be used as a callback to the poll()
		* That just polls for control events.
		*
		* @file: pointer to struct file
		* @wait: pointer to struct poll_table_struct
		*/
		unsigned int v4l2_ctrl_poll(struct file file, struct poll_table_struct wait);

		/* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
		/* Helpers for ioctl_ops */

		/**
		* v4l2_queryctrl - Helper function to implement
		* :ref:`VIDIOC_QUERYCTRL <vidioc_queryctrl>` ioctl
		*
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @qc: pointer to &struct v4l2_queryctrl
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_queryctrl(struct v4l2_ctrl_handler hdl, struct v4l2_queryctrl qc);
		int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler hdl, struct v4l2_query_ext_ctrl qc);

		/**
		* v4l2_query_ext_ctrl - Helper function to implement
		* :ref:`VIDIOC_QUERY_EXT_CTRL <vidioc_queryctrl>` ioctl
		*
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @qc: pointer to &struct v4l2_query_ext_ctrl
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl,
		struct v4l2_query_ext_ctrl *qc);

		/**
		* v4l2_querymenu - Helper function to implement
		* :ref:`VIDIOC_QUERYMENU <vidioc_queryctrl>` ioctl
		*
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @qm: pointer to &struct v4l2_querymenu
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_querymenu(struct v4l2_ctrl_handler hdl, struct v4l2_querymenu qm);

		/**
		* v4l2_g_ctrl - Helper function to implement
		* :ref:`VIDIOC_G_CTRL <vidioc_g_ctrl>` ioctl
		*
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @ctrl: pointer to &struct v4l2_control
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_g_ctrl(struct v4l2_ctrl_handler hdl, struct v4l2_control ctrl);

		/**
		* v4l2_s_ctrl - Helper function to implement
		* :ref:`VIDIOC_S_CTRL <vidioc_g_ctrl>` ioctl
		*
		* @fh: pointer to &struct v4l2_fh
		* @hdl: pointer to &struct v4l2_ctrl_handler
		*
		* @ctrl: pointer to &struct v4l2_control
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_s_ctrl(struct v4l2_fh fh, struct v4l2_ctrl_handler hdl,
		struct v4l2_control *ctrl);
		int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler hdl, struct v4l2_ext_controls c);
		int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler hdl, struct v4l2_ext_controls c);

		/**
		* v4l2_g_ext_ctrls - Helper function to implement
		* :ref:`VIDIOC_G_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
		*
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @c: pointer to &struct v4l2_ext_controls
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl,
		struct v4l2_ext_controls *c);

		/**
		* v4l2_try_ext_ctrls - Helper function to implement
		* :ref:`VIDIOC_TRY_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
		*
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @c: pointer to &struct v4l2_ext_controls
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
		struct v4l2_ext_controls *c);

		/**
		* v4l2_s_ext_ctrls - Helper function to implement
		* :ref:`VIDIOC_S_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
		*
		* @fh: pointer to &struct v4l2_fh
		* @hdl: pointer to &struct v4l2_ctrl_handler
		* @c: pointer to &struct v4l2_ext_controls
		*
		* If hdl == NULL then they will all return -EINVAL.
		*/
		int v4l2_s_ext_ctrls(struct v4l2_fh fh, struct v4l2_ctrl_handler hdl,
		struct v4l2_ext_controls *c);

		/* Can be used as a subscribe_event function that just subscribes control
		events. */
		/**
		* v4l2_ctrl_subdev_subscribe_event - Helper function to implement
		* as a &struct v4l2_subdev_core_ops subscribe_event function
		* that just subscribes control events.
		*
		* @sd: pointer to &struct v4l2_subdev
		* @fh: pointer to &struct v4l2_fh
		* @sub: pointer to &struct v4l2_event_subscription
		*/
		int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev sd, struct v4l2_fh fh,
		struct v4l2_event_subscription *sub);

		/* Log all controls owned by subdev's control handler. */
		/**
		* v4l2_ctrl_subdev_log_status - Log all controls owned by subdev's control
		* handler.
		*
		* @sd: pointer to &struct v4l2_subdev
		*/
		int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);

		#endif