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c3b5b024 SA |
1 | /* |
2 | * v4l2-event.h | |
3 | * | |
4 | * V4L2 events. | |
5 | * | |
6 | * Copyright (C) 2009--2010 Nokia Corporation. | |
7 | * | |
8c5dff90 | 8 | * Contact: Sakari Ailus <sakari.ailus@iki.fi> |
c3b5b024 SA |
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 | ||
3ad57c33 HV |
32 | /* |
33 | * Overview: | |
34 | * | |
35 | * Events are subscribed per-filehandle. An event specification consists of a | |
36 | * type and is optionally associated with an object identified through the | |
37 | * 'id' field. So an event is uniquely identified by the (type, id) tuple. | |
38 | * | |
39 | * The v4l2-fh struct has a list of subscribed events. The v4l2_subscribed_event | |
40 | * struct is added to that list, one for every subscribed event. | |
41 | * | |
42 | * Each v4l2_subscribed_event struct ends with an array of v4l2_kevent structs. | |
43 | * This array (ringbuffer, really) is used to store any events raised by the | |
44 | * driver. The v4l2_kevent struct links into the 'available' list of the | |
45 | * v4l2_fh struct so VIDIOC_DQEVENT will know which event to dequeue first. | |
46 | * | |
47 | * Finally, if the event subscription is associated with a particular object | |
48 | * such as a V4L2 control, then that object needs to know about that as well | |
49 | * so that an event can be raised by that object. So the 'node' field can | |
50 | * be used to link the v4l2_subscribed_event struct into a list of that | |
51 | * object. | |
52 | * | |
53 | * So to summarize: | |
54 | * | |
55 | * struct v4l2_fh has two lists: one of the subscribed events, and one of the | |
56 | * pending events. | |
57 | * | |
58 | * struct v4l2_subscribed_event has a ringbuffer of raised (pending) events of | |
59 | * that particular type. | |
60 | * | |
61 | * If struct v4l2_subscribed_event is associated with a specific object, then | |
62 | * that object will have an internal list of struct v4l2_subscribed_event so | |
63 | * it knows who subscribed an event to that object. | |
64 | */ | |
65 | ||
c3b5b024 | 66 | struct v4l2_fh; |
4f4d14b7 | 67 | struct v4l2_subdev; |
f1e393de | 68 | struct v4l2_subscribed_event; |
c3b5b024 SA |
69 | struct video_device; |
70 | ||
3f66f0ed HV |
71 | /** struct v4l2_kevent - Internal kernel event struct. |
72 | * @list: List node for the v4l2_fh->available list. | |
73 | * @sev: Pointer to parent v4l2_subscribed_event. | |
74 | * @event: The event itself. | |
75 | */ | |
c3b5b024 SA |
76 | struct v4l2_kevent { |
77 | struct list_head list; | |
f1e393de | 78 | struct v4l2_subscribed_event *sev; |
c3b5b024 SA |
79 | struct v4l2_event event; |
80 | }; | |
81 | ||
c53c2549 HG |
82 | /** struct v4l2_subscribed_event_ops - Subscribed event operations. |
83 | * @add: Optional callback, called when a new listener is added | |
84 | * @del: Optional callback, called when a listener stops listening | |
85 | * @replace: Optional callback that can replace event 'old' with event 'new'. | |
86 | * @merge: Optional callback that can merge event 'old' into event 'new'. | |
87 | */ | |
88 | struct v4l2_subscribed_event_ops { | |
6e6d76cd | 89 | int (*add)(struct v4l2_subscribed_event *sev, unsigned elems); |
c53c2549 HG |
90 | void (*del)(struct v4l2_subscribed_event *sev); |
91 | void (*replace)(struct v4l2_event *old, const struct v4l2_event *new); | |
92 | void (*merge)(const struct v4l2_event *old, struct v4l2_event *new); | |
93 | }; | |
94 | ||
3f66f0ed HV |
95 | /** struct v4l2_subscribed_event - Internal struct representing a subscribed event. |
96 | * @list: List node for the v4l2_fh->subscribed list. | |
97 | * @type: Event type. | |
98 | * @id: Associated object ID (e.g. control ID). 0 if there isn't any. | |
99 | * @flags: Copy of v4l2_event_subscription->flags. | |
100 | * @fh: Filehandle that subscribed to this event. | |
101 | * @node: List node that hooks into the object's event list (if there is one). | |
c53c2549 | 102 | * @ops: v4l2_subscribed_event_ops |
3f66f0ed HV |
103 | * @elems: The number of elements in the events array. |
104 | * @first: The index of the events containing the oldest available event. | |
105 | * @in_use: The number of queued events. | |
106 | * @events: An array of @elems events. | |
107 | */ | |
c3b5b024 SA |
108 | struct v4l2_subscribed_event { |
109 | struct list_head list; | |
110 | u32 type; | |
6e239399 | 111 | u32 id; |
77068d36 | 112 | u32 flags; |
77068d36 | 113 | struct v4l2_fh *fh; |
77068d36 | 114 | struct list_head node; |
c53c2549 | 115 | const struct v4l2_subscribed_event_ops *ops; |
f1e393de | 116 | unsigned elems; |
f1e393de | 117 | unsigned first; |
f1e393de | 118 | unsigned in_use; |
f1e393de | 119 | struct v4l2_kevent events[]; |
c3b5b024 SA |
120 | }; |
121 | ||
c3b5b024 SA |
122 | int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, |
123 | int nonblocking); | |
124 | void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev); | |
6e239399 | 125 | void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev); |
c3b5b024 SA |
126 | int v4l2_event_pending(struct v4l2_fh *fh); |
127 | int v4l2_event_subscribe(struct v4l2_fh *fh, | |
85f5fe39 | 128 | const struct v4l2_event_subscription *sub, unsigned elems, |
c53c2549 | 129 | const struct v4l2_subscribed_event_ops *ops); |
c3b5b024 | 130 | int v4l2_event_unsubscribe(struct v4l2_fh *fh, |
85f5fe39 | 131 | const struct v4l2_event_subscription *sub); |
f1e393de | 132 | void v4l2_event_unsubscribe_all(struct v4l2_fh *fh); |
4f4d14b7 SN |
133 | int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh, |
134 | struct v4l2_event_subscription *sub); | |
3cbe6e5b AK |
135 | int v4l2_src_change_event_subscribe(struct v4l2_fh *fh, |
136 | const struct v4l2_event_subscription *sub); | |
137 | int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd, | |
138 | struct v4l2_fh *fh, struct v4l2_event_subscription *sub); | |
c3b5b024 | 139 | #endif /* V4L2_EVENT_H */ |