include/media/v4l2-event.h

   1 /*
   2  * v4l2-event.h
   3  *
   4  * V4L2 events.
   5  *
   6  * Copyright (C) 2009--2010 Nokia Corporation.
   7  *
   8  * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * version 2 as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  22  * 02110-1301 USA
  23  */
  24
  25 #ifndef V4L2_EVENT_H
  26 #define V4L2_EVENT_H
  27
  28 #include <linux/types.h>
  29 #include <linux/videodev2.h>
  30 #include <linux/wait.h>
  31
  32 struct v4l2_fh;
  33 struct v4l2_subscribed_event;
  34 struct video_device;
  35
  36 /** struct v4l2_kevent - Internal kernel event struct.
  37   * @list:      List node for the v4l2_fh->available list.
  38   * @sev:       Pointer to parent v4l2_subscribed_event.
  39   * @event:     The event itself.
  40   */
  41 struct v4l2_kevent {
  42         struct list_head        list;
  43         struct v4l2_subscribed_event *sev;
  44         struct v4l2_event       event;
  45 };
  46
  47 /** struct v4l2_subscribed_event - Internal struct representing a subscribed event.
  48   * @list:      List node for the v4l2_fh->subscribed list.
  49   * @type:      Event type.
  50   * @id:        Associated object ID (e.g. control ID). 0 if there isn't any.
  51   * @flags:     Copy of v4l2_event_subscription->flags.
  52   * @fh:        Filehandle that subscribed to this event.
  53   * @node:      List node that hooks into the object's event list (if there is one).
  54   * @replace:   Optional callback that can replace event 'old' with event 'new'.
  55   * @merge:     Optional callback that can merge event 'old' into event 'new'.
  56   * @elems:     The number of elements in the events array.
  57   * @first:     The index of the events containing the oldest available event.
  58   * @in_use:    The number of queued events.
  59   * @events:    An array of @elems events.
  60   */
  61 struct v4l2_subscribed_event {
  62         struct list_head        list;
  63         u32                     type;
  64         u32                     id;
  65         u32                     flags;
  66         struct v4l2_fh          *fh;
  67         struct list_head        node;
  68         void                    (*replace)(struct v4l2_event *old,
  69                                            const struct v4l2_event *new);
  70         void                    (*merge)(const struct v4l2_event *old,
  71                                          struct v4l2_event *new);
  72         unsigned                elems;
  73         unsigned                first;
  74         unsigned                in_use;
  75         struct v4l2_kevent      events[];
  76 };
  77
  78 int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
  79                        int nonblocking);
  80 void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev);
  81 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev);
  82 int v4l2_event_pending(struct v4l2_fh *fh);
  83 int v4l2_event_subscribe(struct v4l2_fh *fh,
  84                          struct v4l2_event_subscription *sub, unsigned elems);
  85 int v4l2_event_unsubscribe(struct v4l2_fh *fh,
  86                            struct v4l2_event_subscription *sub);
  87 void v4l2_event_unsubscribe_all(struct v4l2_fh *fh);
  88
  89 #endif /* V4L2_EVENT_H */