/*

   *  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
  #define _V4L2_CTRLS_H
  
  #include <linux/list.h>

  #include <linux/mutex.h>

  #include <linux/videodev2.h>

  
  /* forward references */

  struct file;

  struct v4l2_ctrl_handler;

  struct v4l2_ctrl_helper;

  struct v4l2_ctrl;
  struct video_device;
  struct v4l2_subdev;

  struct v4l2_subscribed_event;

  struct v4l2_fh;

  struct poll_table_struct;

  /**
   * union v4l2_ctrl_ptr - A pointer to a control value.

   * @p_s32:	Pointer to a 32-bit signed value.
   * @p_s64:	Pointer to a 64-bit signed value.

   * @p_u8:	Pointer to a 8-bit unsigned value.
   * @p_u16:	Pointer to a 16-bit unsigned value.

   * @p_u32:	Pointer to a 32-bit unsigned value.

   * @p_char:	Pointer to a string.
   * @p:		Pointer to a compound value.
   */
  union v4l2_ctrl_ptr {
  	s32 *p_s32;
  	s64 *p_s64;

  	u8 *p_u8;
  	u16 *p_u16;

  	u32 *p_u32;

  	char *p_char;
  	void *p;
  };

  /**
   * 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
   *		continuously.
   *		If not set, then the currently cached value will be returned.
   * @try_ctrl:	Test whether the control's value is valid. Only relevant when
   *		the usual min/max/step checks are not sufficient.
   * @s_ctrl:	Actually set the new control value. s_ctrl is compulsory. The
   *		ctrl->handler->lock is held when these ops are called, so no
   *		one else can access controls owned by that handler.
   */

  struct v4l2_ctrl_ops {
  	int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
  	int (*try_ctrl)(struct v4l2_ctrl *ctrl);
  	int (*s_ctrl)(struct v4l2_ctrl *ctrl);
  };

  /**
   * struct v4l2_ctrl_type_ops - The control type operations that the driver

   *			       has to provide.

   *
   * @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.

   */

  struct v4l2_ctrl_type_ops {

  	bool (*equal)(const struct v4l2_ctrl *ctrl, u32 idx,

  		      union v4l2_ctrl_ptr ptr1,
  		      union v4l2_ctrl_ptr ptr2);

  	void (*init)(const struct v4l2_ctrl *ctrl, u32 idx,

  		     union v4l2_ctrl_ptr ptr);
  	void (*log)(const struct v4l2_ctrl *ctrl);

  	int (*validate)(const struct v4l2_ctrl *ctrl, u32 idx,

  			union v4l2_ctrl_ptr ptr);
  };

  /**
   * typedef v4l2_ctrl_notify_fnc - typedef for a notify argument with a function
   *	that should be called when a control value has changed.
   *
   * @ctrl: pointer to struct &v4l2_ctrl
   * @priv: control private data
   *
   * This typedef definition is used as an argument to v4l2_ctrl_notify()
   * and as an argument at struct &v4l2_ctrl_handler.
   */

  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.
   * @cluster:	Point to start of cluster array.
   * @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

   *		should never set this flag.
   * @has_changed: Set when the current value differs from the new value. Drivers
   *		should never use this flag.
   * @is_private: If set, then this control is private to its handler and it
   *		will not be added to any other handlers. Drivers can set
   *		this flag.
   * @is_auto:   If set, then this control selects whether the other cluster
   *		members are in 'automatic' mode or 'manual' mode. This is
   *		used for autogain/gain type clusters. Drivers should never
   *		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

   *		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.
   *		Drivers should never touch this flag.
   * @call_notify: If set, then call the handler's notify function whenever the
   *		control's value changes.
   * @manual_mode_value: If the is_auto flag is set, then this is the value
   *		of the auto control that determines if that control is in
   *		manual mode. So if the value of the auto control equals this
   *		value, then the whole cluster is in manual mode. Drivers should
   *		never set this flag directly.
   * @ops:	The control ops.
   * @type_ops:	The control type ops.
   * @id:	The control ID.
   * @name:	The control name.
   * @type:	The control type.
   * @minimum:	The control's minimum value.
   * @maximum:	The control's maximum value.
   * @default_value: The control's default value.
   * @step:	The control's step value for non-menu controls.
   * @elems:	The number of elements in the N-dimensional array.
   * @elem_size:	The size in bytes of the control.
   * @dims:	The size of each dimension.
   * @nr_of_dims:The number of dimensions in @dims.
   * @menu_skip_mask: The control's skip mask for menu controls. This makes it
   *		easy to skip menu items that are not valid. If bit X is set,
   *		then menu item X is skipped. Of course, this only works for
   *		menus with <= 32 menu items. There are no menus that come
   *		close to that number, so this is OK. Should we ever need more,
   *		then this will have to be extended to a u64 or a bit array.
   * @qmenu:	A const char * array for all menu items. Array entries that are
   *		empty strings ("") correspond to non-existing menu items (this
   *		is in addition to the menu_skip_mask above). The last entry
   *		must be NULL.
   * @flags:	The control's flags.
   * @cur:	The control's current value.
   * @val:	The control's new s32 value.

   * @priv:	The control's private pointer. For use by the driver. It is
   *		untouched by the control framework. Note that this pointer is
   *		not freed when the control is deleted. Should this be needed
   *		then a new internal bitfield can be added to tell the framework
   *		to free this pointer.

   * @p_cur:	The control's current value represented via a union with

   *		provides a standard way of accessing control types
   *		through a pointer.

   * @p_new:	The control's new value represented via a union with provides

   *		a standard way of accessing control types
   *		through a pointer.

   */

  struct v4l2_ctrl {
  	/* Administrative fields */
  	struct list_head node;

  	struct list_head ev_subs;

  	struct v4l2_ctrl_handler *handler;
  	struct v4l2_ctrl **cluster;

  	unsigned int ncontrols;

  	unsigned int done:1;

  	unsigned int is_new:1;

  	unsigned int has_changed:1;

  	unsigned int is_private:1;

  	unsigned int is_auto:1;

  	unsigned int is_int:1;
  	unsigned int is_string:1;
  	unsigned int is_ptr:1;

  	unsigned int is_array:1;

  	unsigned int has_volatiles:1;

  	unsigned int call_notify:1;

  	unsigned int manual_mode_value:8;

  
  	const struct v4l2_ctrl_ops *ops;

  	const struct v4l2_ctrl_type_ops *type_ops;

  	u32 id;
  	const char *name;
  	enum v4l2_ctrl_type type;

  	s64 minimum, maximum, default_value;

  	u32 elems;

  	u32 elem_size;

  	u32 dims[V4L2_CTRL_MAX_DIMS];
  	u32 nr_of_dims;

  	union {

  		u64 step;
  		u64 menu_skip_mask;

  	};

  	union {
  		const char * const *qmenu;
  		const s64 *qmenu_int;
  	};

  	unsigned long flags;

  	void *priv;

  	s32 val;
  	struct {

  		s32 val;

  	} cur;

  
  	union v4l2_ctrl_ptr p_new;
  	union v4l2_ctrl_ptr p_cur;

  };

  /**
   * 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`` function at ``v4l2-ctrl.c``.

   *
   * 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
   * is used to link the control in the hash's bucket.
   */

  struct v4l2_ctrl_ref {
  	struct list_head node;
  	struct v4l2_ctrl_ref *next;
  	struct v4l2_ctrl *ctrl;

  	struct v4l2_ctrl_helper *helper;

  };

  /**
   * 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.
   * @ctrls:	The list of controls owned by this handler.
   * @ctrl_refs:	The list of control references.
   * @cached:	The last found control reference. It is common that the same
   *		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.

   *		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.
   * @nr_of_buckets: Total number of buckets in the array.
   * @error:	The error code of the first failed control addition.
   */

  struct v4l2_ctrl_handler {

  	struct mutex _lock;
  	struct mutex *lock;

  	struct list_head ctrls;
  	struct list_head ctrl_refs;
  	struct v4l2_ctrl_ref *cached;
  	struct v4l2_ctrl_ref **buckets;

  	v4l2_ctrl_notify_fnc notify;
  	void *notify_priv;

  	u16 nr_of_buckets;
  	int error;
  };

  /**
   * 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.
   * @name:	The control name.
   * @type:	The control type.
   * @min:	The control's minimum value.
   * @max:	The control's maximum value.
   * @step:	The control's step value for non-menu controls.

   * @def:	The control's default value.

   * @dims:	The size of each dimension.
   * @elem_size:	The size in bytes of the control.
   * @flags:	The control's flags.
   * @menu_skip_mask: The control's skip mask for menu controls. This makes it
   *		easy to skip menu items that are not valid. If bit X is set,
   *		then menu item X is skipped. Of course, this only works for
   *		menus with <= 64 menu items. There are no menus that come
   *		close to that number, so this is OK. Should we ever need more,
   *		then this will have to be extended to a bit array.
   * @qmenu:	A const char * array for all menu items. Array entries that are
   *		empty strings ("") correspond to non-existing menu items (this
   *		is in addition to the menu_skip_mask above). The last entry
   *		must be NULL.

   * @qmenu_int:	A const s64 integer array for all menu items of the type

   *		V4L2_CTRL_TYPE_INTEGER_MENU.

   * @is_private: If set, then this control is private to its handler and it
   *		will not be added to any other handlers.
   */

  struct v4l2_ctrl_config {
  	const struct v4l2_ctrl_ops *ops;

  	const struct v4l2_ctrl_type_ops *type_ops;

  	u32 id;
  	const char *name;
  	enum v4l2_ctrl_type type;

  	s64 min;
  	s64 max;
  	u64 step;
  	s64 def;

  	u32 dims[V4L2_CTRL_MAX_DIMS];

  	u32 elem_size;

  	u32 flags;

  	u64 menu_skip_mask;

  	const char * const *qmenu;

  	const s64 *qmenu_int;

  	unsigned int is_private:1;

  };

  /**
   * v4l2_ctrl_fill - Fill in the control fields based on the control ID.
   *
   * @id: ID of the control

   * @name: pointer to be filled with a string with the name of the control
   * @type: pointer for storing the type of the control
   * @min: pointer for storing the minimum value for the control
   * @max: pointer for storing the maximum value for the control
   * @step: pointer for storing the control step
   * @def: pointer for storing the default value for the control
   * @flags: pointer for storing the 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 content will be set to %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.

   */

  void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,

  		    s64 *min, s64 *max, u64 *step, s64 *def, u32 *flags);

  /**
   * v4l2_ctrl_handler_init_class() - Initialize the control handler.
   * @hdl:	The control handler.
   * @nr_of_controls_hint: A hint of how many controls this handler is
   *		expected to refer to. This is the total number, so including
   *		any inherited controls. It doesn't have to be precise, but if
   *		it is way off, then you either waste memory (too many buckets
   *		are allocated) or the control lookup becomes slower (not enough
   *		buckets are allocated, so there are more slow list lookups).
   *		It will always work, though.
   * @key:	Used by the lock validator if CONFIG_LOCKDEP is set.
   * @name:	Used by the lock validator if CONFIG_LOCKDEP is set.
   *

   * .. attention::
   *
   *    Never use this call directly, always use the v4l2_ctrl_handler_init()
   *    macro that hides the @key and @name arguments.

   *

   * Return: returns an error if the buckets could not be allocated. This
   * error will also be stored in @hdl->error.

   */

  int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,

  				 unsigned int nr_of_controls_hint,

  				 struct lock_class_key *key, const char *name);
  
  #ifdef CONFIG_LOCKDEP

  
  /**

   * v4l2_ctrl_handler_init - helper function to create a static struct
   *	 &lock_class_key and calls v4l2_ctrl_handler_init_class()

   *
   * @hdl:	The control handler.
   * @nr_of_controls_hint: A hint of how many controls this handler is
   *		expected to refer to. This is the total number, so including
   *		any inherited controls. It doesn't have to be precise, but if
   *		it is way off, then you either waste memory (too many buckets
   *		are allocated) or the control lookup becomes slower (not enough
   *		buckets are allocated, so there are more slow list lookups).
   *		It will always work, though.
   *
   * This helper function creates a static struct &lock_class_key and
   * calls v4l2_ctrl_handler_init_class(), providing a proper name for the lock
   * validador.
   *
   * Use this helper function to initialize a control handler.
   */

  #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
  (									\
  	({								\
  		static struct lock_class_key _key;			\
  		v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint,	\
  					&_key,				\
  					KBUILD_BASENAME ":"		\
  					__stringify(__LINE__) ":"	\
  					"(" #hdl ")->_lock");		\
  	})								\
  )
  #else
  #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
  	v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, NULL, NULL)
  #endif

  /**
   * v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
   * the control list.
   * @hdl:	The control handler.
   *
   * Does nothing if @hdl == NULL.
   */

  void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);

  /**
   * v4l2_ctrl_lock() - Helper function to lock the handler
   * associated with the control.
   * @ctrl:	The control to lock.
   */

  static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
  {
  	mutex_lock(ctrl->handler->lock);
  }

  /**
   * v4l2_ctrl_unlock() - Helper function to unlock the handler
   * associated with the control.
   * @ctrl:	The control to unlock.
   */

  static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
  {
  	mutex_unlock(ctrl->handler->lock);
  }

  /**

   * __v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
   * to the handler to initialize the hardware to the current control values. The
   * caller is responsible for acquiring the control handler mutex on behalf of
   * __v4l2_ctrl_handler_setup().
   * @hdl:	The control handler.
   *
   * Button controls will be skipped, as are read-only controls.
   *
   * If @hdl == NULL, then this just returns 0.
   */
  int __v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
  
  /**

   * v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
   * to the handler to initialize the hardware to the current control values.
   * @hdl:	The control handler.
   *
   * Button controls will be skipped, as are read-only controls.
   *
   * If @hdl == NULL, then this just returns 0.
   */

  int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);

  /**
   * v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
   * @hdl:	The control handler.
   * @prefix:	The prefix to use when logging the control values. If the
   *		prefix does not end with a space, then ": " will be added
   *		after the prefix. If @prefix == NULL, then no prefix will be
   *		used.
   *
   * For use with VIDIOC_LOG_STATUS.
   *
   * Does nothing if @hdl == NULL.
   */

  void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
  				  const char *prefix);

  /**
   * 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.
   *
   * If the &v4l2_ctrl struct could not be allocated then NULL is returned
   * 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);

  /**

   * 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.

   * @min:	The control's minimum value.
   * @max:	The control's maximum value.
   * @step:	The control's step value

   * @def:	The control's default value.

   *
   * If the &v4l2_ctrl struct could not be allocated, or the control
   * ID is not known, then NULL is returned and @hdl->error is set to the
   * appropriate error code (if it wasn't set already).
   *
   * If @id refers to a menu control, then this function will return NULL.
   *
   * Use v4l2_ctrl_new_std_menu() when adding menu controls.
   */

  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);

  /**

   * 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.

   * @max:	The control's maximum value.

   * @mask:	The control's skip mask for menu controls. This makes it

   *		easy to skip menu items that are not valid. If bit X is set,
   *		then menu item X is skipped. Of course, this only works for
   *		menus with <= 64 menu items. There are no menus that come
   *		close to that number, so this is OK. Should we ever need more,
   *		then this will have to be extended to a bit array.

   * @def:	The control's default value.

   *
   * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
   * determines which menu items are to be skipped.
   *
   * If @id refers to a non-menu control, then this function will return NULL.
   */

  struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,

  					 const struct v4l2_ctrl_ops *ops,
  					 u32 id, u8 max, u64 mask, u8 def);

  /**
   * 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.
   * @max:	The control's maximum value.
   * @mask:	The control's skip mask for menu controls. This makes it
   *		easy to skip menu items that are not valid. If bit X is set,
   *		then menu item X is skipped. Of course, this only works for
   *		menus with <= 64 menu items. There are no menus that come
   *		close to that number, so this is OK. Should we ever need more,
   *		then this will have to be extended to a bit array.
   * @def:	The control's default value.
   * @qmenu:	The new menu.
   *
   * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific
   * menu of this control.
   *
   */

  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);

  /**
   * 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.
   * @max:	The control's maximum value.
   * @def:	The control's default value.
   * @qmenu_int:	The control's menu entries.
   *
   * 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.

   */

  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);

  /**
   * typedef v4l2_ctrl_filter - Typedef to define the filter function to be
   *	used when adding a control handler.
   *
   * @ctrl: pointer to struct &v4l2_ctrl.
   */

  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.
   * @filter:	This function will filter which controls should be added.
   *
   * Does nothing if either of the two handlers is a NULL pointer.
   * If @filter is NULL, then all controls are added. Otherwise only those
   * controls for which @filter returns true will be added.
   * In case of an error @hdl->error will be set to the error code (if it
   * wasn't set already).
   */

  int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,

  			  struct v4l2_ctrl_handler *add,

  			  v4l2_ctrl_filter filter);

  /**
   * 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
   * nodes. Those are all of the V4L2_CID_AUDIO_* user controls and all FM
   * transmitter class controls.
   *
   * This function is to be used with v4l2_ctrl_add_handler().
   */

  bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);

  /**

   * 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 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.
   *

   * @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.)
   * @manual_val: The value for the first control in the cluster that equals the
   *		manual setting.
   * @set_volatile: If true, then all controls except the first auto control will
   *		be volatile.
   *
   * Use for control groups where one control selects some automatic feature and
   * the other controls are only active whenever the automatic feature is turned
   * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
   * red and blue balance, etc.
   *
   * The behavior of such controls is as follows:
   *
   * When the autofoo control is set to automatic, then any manual controls
   * are set to inactive and any reads will call g_volatile_ctrl (if the control
   * was marked volatile).
   *
   * When the autofoo control is set to manual, then any manual controls will
   * be marked active, and any reads will just return the current value without
   * going through g_volatile_ctrl.
   *

   * In addition, this function will set the %V4L2_CTRL_FLAG_UPDATE flag
   * 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 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.
   *
   * If @hdl == NULL this will return NULL as well. Will lock the handler so
   * do not use from inside &v4l2_ctrl_ops.
   */

  struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);

  /**
   * v4l2_ctrl_activate() - Make the control active or inactive.
   * @ctrl:	The control to (de)activate.
   * @active:	True if the control should become active.
   *
   * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
   * Does nothing if @ctrl == NULL.
   * This will usually be called from within the s_ctrl op.
   * The V4L2_EVENT_CTRL event will be generated afterwards.
   *
   * This function assumes that the control handler is locked.
   */

  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.
   *
   * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
   * Does nothing if @ctrl == NULL.
   * The V4L2_EVENT_CTRL event will be generated afterwards.
   * This will usually be called when starting or stopping streaming in the
   * driver.
   *
   * This function assumes that the control handler is not locked and will
   * take the lock itself.
   */

  void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);

  /**
   *__v4l2_ctrl_modify_range() - Unlocked variant of v4l2_ctrl_modify_range()
   *
   * @ctrl:	The control to update.
   * @min:	The control's minimum value.
   * @max:	The control's maximum value.
   * @step:	The control's step value
   * @def:	The control's default value.
   *
   * Update the range of a control on the fly. This works for control types
   * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
   * @step value is interpreted as a menu_skip_mask.
   *
   * An error is returned if one of the range arguments is invalid for this
   * control type.
   *
   * This function assumes that the control handler is not locked and will
   * take the lock itself.
   */

  int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
  			     s64 min, s64 max, u64 step, s64 def);

  /**
   * 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.
   * @step:	The control's step value
   * @def:	The control's default value.
   *
   * Update the range of a control on the fly. This works for control types
   * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
   * @step value is interpreted as a menu_skip_mask.
   *
   * An error is returned if one of the range arguments is invalid for this
   * control type.
   *
   * This function assumes that the control handler is not locked and will
   * take the lock itself.
   */

  static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
  					 s64 min, s64 max, u64 step, s64 def)
  {
  	int rval;
  
  	v4l2_ctrl_lock(ctrl);
  	rval = __v4l2_ctrl_modify_range(ctrl, min, max, step, def);
  	v4l2_ctrl_unlock(ctrl);
  
  	return rval;
  }

  /**
   * 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.
   *
   * This function sets a callback function for the control. If @ctrl is NULL,
   * then it will do nothing. If @notify is NULL, then the notify callback will
   * be removed.
   *
   * 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);

  /**
   * 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
   * a known control.
   */
  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
   * given control ID or NULL if it isn't a known menu control.
   */
  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.
   *
   * This function returns the integer array of the given control ID or NULL if it
   * if it isn't a known integer menu control.
   */
  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.
   *

   * @ctrl:	The control.
   *
   * This returns the control's value 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.
   *
   * This function is for integer type controls only.
   */

  s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);

  /**
   * __v4l2_ctrl_s_ctrl() - Unlocked variant of v4l2_ctrl_s_ctrl().

   *

   * @ctrl:	The control.

   * @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,
   * allowing it to be used from within the &v4l2_ctrl_ops functions.

   *
   * This function is for integer type controls only.
   */

  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.

   * @ctrl:	The control.
   * @val:	The new value.
   *

   * This sets the control's new value 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.
   *
   * This function is for integer type controls only.
   */

  static inline int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
  {
  	int rval;
  
  	v4l2_ctrl_lock(ctrl);
  	rval = __v4l2_ctrl_s_ctrl(ctrl, val);
  	v4l2_ctrl_unlock(ctrl);
  
  	return rval;
  }

  /**
   * 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
   * framework. This function will lock the control's handler, so it cannot be
   * used from within the &v4l2_ctrl_ops functions.
   *
   * This function is for 64-bit integer type controls only.
   */

  s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl);

  /**
   * __v4l2_ctrl_s_ctrl_int64() - Unlocked variant of v4l2_ctrl_s_ctrl_int64().
   *
   * @ctrl:	The control.
   * @val:	The 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,
   * allowing it to be used from within the &v4l2_ctrl_ops functions.

   *
   * This function is for 64-bit integer type controls only.
   */

  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

   *	from within a driver.
   *
   * @ctrl:	The control.
   * @val:	The new value.
   *

   * This sets the control's new value 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.
   *
   * This function is for 64-bit integer type controls only.
   */

  static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
  {
  	int rval;
  
  	v4l2_ctrl_lock(ctrl);
  	rval = __v4l2_ctrl_s_ctrl_int64(ctrl, val);
  	v4l2_ctrl_unlock(ctrl);
  
  	return rval;
  }

  /**
   * __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string().

   *
   * @ctrl:	The control.
   * @s:		The new string.
   *

   * This sets the control's new string safely by going through the control
   * framework. This function assumes the control's handler is already locked,
   * allowing it to be used from within the &v4l2_ctrl_ops functions.

   *
   * This function is for string type controls only.
   */

  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

   *	 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.
   *
   * This function is for string type controls only.
   */

  static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
  {
  	int rval;
  
  	v4l2_ctrl_lock(ctrl);
  	rval = __v4l2_ctrl_s_ctrl_string(ctrl, s);
  	v4l2_ctrl_unlock(ctrl);
  
  	return rval;
  }

  /* 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 struct &v4l2_event with the reported

   *	 event;

   * @new: pointer to struct &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 struct &v4l2_event with the reported

   *	 event;

   * @new: pointer to struct &v4l2_event with the merged

   *	 event;
   */

  void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new);

  /**
   * 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);

  /**
   * 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);

  /**
   * 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 */
  
  /**
   * 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);

  
  /**
   * 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);
  
  /**
   * 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);

  /**
   * 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);

  /**
   * 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