/*
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
*/
#ifndef _V4L2_CTRLS_H
#define _V4L2_CTRLS_H
#include <linux/list.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;
/** 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);
};
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.
* @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.
* @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.
* @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.
* @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.
* @val64: The control's new s64 value.
* @string: The control's new string 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.
*/
struct v4l2_ctrl {
/* Administrative fields */
struct list_head node;
struct list_head ev_subs;
struct v4l2_ctrl_handler *handler;
struct v4l2_ctrl **cluster;
unsigned ncontrols;
unsigned int done:1;
unsigned int is_new:1;
unsigned int is_private:1;
unsigned int is_auto:1;
unsigned int has_volatiles:1;
unsigned int call_notify:1;
unsigned int manual_mode_value:8;
const struct v4l2_ctrl_ops *ops;
u32 id;
const char *name;
enum v4l2_ctrl_type type;
s32 minimum, maximum, default_value;
union {
u32 step;
u32 menu_skip_mask;
};
union {
const char * const *qmenu;
const s64 *qmenu_int;
};
unsigned long flags;
union {
s32 val;
s64 val64;
char *string;
} cur;
union {
s32 val;
s64 val64;
char *string;
};
void *priv;
};
/** 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().
*
* 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.
* @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.
* @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 <= 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.
* @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;
u32 id;
const char *name;
enum v4l2_ctrl_type type;
s32 min;
s32 max;
u32 step;
s32 def;
u32 flags;
u32 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.
*
* This works for all standard V4L2 controls.
* For non-standard controls it will only fill in the given arguments
* 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.
*
* 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,
s32 *min, s32 *max, s32 *step, s32 *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.
*
* Returns an error if the buckets could not be allocated. This error will
* also be stored in @hdl->error.
*
* Never use this call directly, always use the v4l2_ctrl_handler_init
* macro that hides the @key and @name arguments.
*/
int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
unsigned nr_of_controls_hint,
struct lock_class_key *key, const char *name);
#ifdef CONFIG_LOCKDEP
#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_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, s32 min, s32 max, u32 step, s32 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 <= 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.
* @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, s32 max, s32 mask, s32 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 <= 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.
* @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, s32 max,
s32 mask, s32 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, s32 max, s32 def, const s64 *qmenu_int);
/** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
* @hdl: The control handler.
* @ctrl: The control to add.
*
* It will return NULL if it was unable to add the control reference.
* If the control already belonged to the handler, then it will do
* nothing and just return @ctrl.
*/
struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
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,
bool (*filter)(const struct v4l2_ctrl *ctrl));
/** 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 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 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() - 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.
*/
int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
s32 min, s32 max, u32 step, s32 def);
/** 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_lock() - 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_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_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() - Helper function to set the control's value from within a driver.
* @ctrl: The control.
* @val: The new value.
*
* This set 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.
*/
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
* 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() - Helper function to set a 64-bit control's value from within a driver.
* @ctrl: The control.
* @val: The new value.
*
* This set 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.
*/
int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val);
/* Internal helper functions that deal with control events. */
extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);
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. */
int v4l2_ctrl_log_status(struct file *file, void *fh);
/* 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. */
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. */
int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
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);
int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
struct v4l2_ext_controls *c);
/* Helpers for subdevices. If the associated ctrl_handler == NULL then they
will all return -EINVAL. */
int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
/* Can be used as a subscribe_event function that just subscribes control
events. */
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. */
int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);
#endif
