136 lines
5.0 KiB
C
136 lines
5.0 KiB
C
/*
|
|
* v4l2-event.h
|
|
*
|
|
* V4L2 events.
|
|
*
|
|
* Copyright (C) 2009--2010 Nokia Corporation.
|
|
*
|
|
* Contact: Sakari Ailus <sakari.ailus@iki.fi>
|
|
*
|
|
* 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.
|
|
*
|
|
* 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., 51 Franklin St, Fifth Floor, Boston, MA
|
|
* 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef V4L2_EVENT_H
|
|
#define V4L2_EVENT_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/videodev2.h>
|
|
#include <linux/wait.h>
|
|
|
|
/*
|
|
* Overview:
|
|
*
|
|
* Events are subscribed per-filehandle. An event specification consists of a
|
|
* type and is optionally associated with an object identified through the
|
|
* 'id' field. So an event is uniquely identified by the (type, id) tuple.
|
|
*
|
|
* The v4l2-fh struct has a list of subscribed events. The v4l2_subscribed_event
|
|
* struct is added to that list, one for every subscribed event.
|
|
*
|
|
* Each v4l2_subscribed_event struct ends with an array of v4l2_kevent structs.
|
|
* This array (ringbuffer, really) is used to store any events raised by the
|
|
* driver. The v4l2_kevent struct links into the 'available' list of the
|
|
* v4l2_fh struct so VIDIOC_DQEVENT will know which event to dequeue first.
|
|
*
|
|
* Finally, if the event subscription is associated with a particular object
|
|
* such as a V4L2 control, then that object needs to know about that as well
|
|
* so that an event can be raised by that object. So the 'node' field can
|
|
* be used to link the v4l2_subscribed_event struct into a list of that
|
|
* object.
|
|
*
|
|
* So to summarize:
|
|
*
|
|
* struct v4l2_fh has two lists: one of the subscribed events, and one of the
|
|
* pending events.
|
|
*
|
|
* struct v4l2_subscribed_event has a ringbuffer of raised (pending) events of
|
|
* that particular type.
|
|
*
|
|
* If struct v4l2_subscribed_event is associated with a specific object, then
|
|
* that object will have an internal list of struct v4l2_subscribed_event so
|
|
* it knows who subscribed an event to that object.
|
|
*/
|
|
|
|
struct v4l2_fh;
|
|
struct v4l2_subdev;
|
|
struct v4l2_subscribed_event;
|
|
struct video_device;
|
|
|
|
/** struct v4l2_kevent - Internal kernel event struct.
|
|
* @list: List node for the v4l2_fh->available list.
|
|
* @sev: Pointer to parent v4l2_subscribed_event.
|
|
* @event: The event itself.
|
|
*/
|
|
struct v4l2_kevent {
|
|
struct list_head list;
|
|
struct v4l2_subscribed_event *sev;
|
|
struct v4l2_event event;
|
|
};
|
|
|
|
/** struct v4l2_subscribed_event_ops - Subscribed event operations.
|
|
* @add: Optional callback, called when a new listener is added
|
|
* @del: Optional callback, called when a listener stops listening
|
|
* @replace: Optional callback that can replace event 'old' with event 'new'.
|
|
* @merge: Optional callback that can merge event 'old' into event 'new'.
|
|
*/
|
|
struct v4l2_subscribed_event_ops {
|
|
int (*add)(struct v4l2_subscribed_event *sev, unsigned elems);
|
|
void (*del)(struct v4l2_subscribed_event *sev);
|
|
void (*replace)(struct v4l2_event *old, const struct v4l2_event *new);
|
|
void (*merge)(const struct v4l2_event *old, struct v4l2_event *new);
|
|
};
|
|
|
|
/** struct v4l2_subscribed_event - Internal struct representing a subscribed event.
|
|
* @list: List node for the v4l2_fh->subscribed list.
|
|
* @type: Event type.
|
|
* @id: Associated object ID (e.g. control ID). 0 if there isn't any.
|
|
* @flags: Copy of v4l2_event_subscription->flags.
|
|
* @fh: Filehandle that subscribed to this event.
|
|
* @node: List node that hooks into the object's event list (if there is one).
|
|
* @ops: v4l2_subscribed_event_ops
|
|
* @elems: The number of elements in the events array.
|
|
* @first: The index of the events containing the oldest available event.
|
|
* @in_use: The number of queued events.
|
|
* @events: An array of @elems events.
|
|
*/
|
|
struct v4l2_subscribed_event {
|
|
struct list_head list;
|
|
u32 type;
|
|
u32 id;
|
|
u32 flags;
|
|
struct v4l2_fh *fh;
|
|
struct list_head node;
|
|
const struct v4l2_subscribed_event_ops *ops;
|
|
unsigned elems;
|
|
unsigned first;
|
|
unsigned in_use;
|
|
struct v4l2_kevent events[];
|
|
};
|
|
|
|
int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
|
|
int nonblocking);
|
|
void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev);
|
|
void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev);
|
|
int v4l2_event_pending(struct v4l2_fh *fh);
|
|
int v4l2_event_subscribe(struct v4l2_fh *fh,
|
|
const struct v4l2_event_subscription *sub, unsigned elems,
|
|
const struct v4l2_subscribed_event_ops *ops);
|
|
int v4l2_event_unsubscribe(struct v4l2_fh *fh,
|
|
const struct v4l2_event_subscription *sub);
|
|
void v4l2_event_unsubscribe_all(struct v4l2_fh *fh);
|
|
int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh,
|
|
struct v4l2_event_subscription *sub);
|
|
#endif /* V4L2_EVENT_H */
|