1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * v4l2-event.h |
4 | * |
5 | * V4L2 events. |
6 | * |
7 | * Copyright (C) 2009--2010 Nokia Corporation. |
8 | * |
9 | * Contact: Sakari Ailus <sakari.ailus@iki.fi> |
10 | */ |
11 | |
12 | #ifndef V4L2_EVENT_H |
13 | #define V4L2_EVENT_H |
14 | |
15 | #include <linux/types.h> |
16 | #include <linux/videodev2.h> |
17 | #include <linux/wait.h> |
18 | |
19 | struct v4l2_fh; |
20 | struct v4l2_subdev; |
21 | struct v4l2_subscribed_event; |
22 | struct video_device; |
23 | |
24 | /** |
25 | * struct v4l2_kevent - Internal kernel event struct. |
26 | * @list: List node for the v4l2_fh->available list. |
27 | * @sev: Pointer to parent v4l2_subscribed_event. |
28 | * @event: The event itself. |
29 | * @ts: The timestamp of the event. |
30 | */ |
31 | struct v4l2_kevent { |
32 | struct list_head list; |
33 | struct v4l2_subscribed_event *sev; |
34 | struct v4l2_event event; |
35 | u64 ts; |
36 | }; |
37 | |
38 | /** |
39 | * struct v4l2_subscribed_event_ops - Subscribed event operations. |
40 | * |
41 | * @add: Optional callback, called when a new listener is added |
42 | * @del: Optional callback, called when a listener stops listening |
43 | * @replace: Optional callback that can replace event 'old' with event 'new'. |
44 | * @merge: Optional callback that can merge event 'old' into event 'new'. |
45 | */ |
46 | struct v4l2_subscribed_event_ops { |
47 | int (*add)(struct v4l2_subscribed_event *sev, unsigned int elems); |
48 | void (*del)(struct v4l2_subscribed_event *sev); |
49 | void (*replace)(struct v4l2_event *old, const struct v4l2_event *new); |
50 | void (*merge)(const struct v4l2_event *old, struct v4l2_event *new); |
51 | }; |
52 | |
53 | /** |
54 | * struct v4l2_subscribed_event - Internal struct representing a subscribed |
55 | * event. |
56 | * |
57 | * @list: List node for the v4l2_fh->subscribed list. |
58 | * @type: Event type. |
59 | * @id: Associated object ID (e.g. control ID). 0 if there isn't any. |
60 | * @flags: Copy of v4l2_event_subscription->flags. |
61 | * @fh: Filehandle that subscribed to this event. |
62 | * @node: List node that hooks into the object's event list |
63 | * (if there is one). |
64 | * @ops: v4l2_subscribed_event_ops |
65 | * @elems: The number of elements in the events array. |
66 | * @first: The index of the events containing the oldest available event. |
67 | * @in_use: The number of queued events. |
68 | * @events: An array of @elems events. |
69 | */ |
70 | struct v4l2_subscribed_event { |
71 | struct list_head list; |
72 | u32 type; |
73 | u32 id; |
74 | u32 flags; |
75 | struct v4l2_fh *fh; |
76 | struct list_head node; |
77 | const struct v4l2_subscribed_event_ops *ops; |
78 | unsigned int elems; |
79 | unsigned int first; |
80 | unsigned int in_use; |
81 | struct v4l2_kevent events[] __counted_by(elems); |
82 | }; |
83 | |
84 | /** |
85 | * v4l2_event_dequeue - Dequeue events from video device. |
86 | * |
87 | * @fh: pointer to struct v4l2_fh |
88 | * @event: pointer to struct v4l2_event |
89 | * @nonblocking: if not zero, waits for an event to arrive |
90 | */ |
91 | int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, |
92 | int nonblocking); |
93 | |
94 | /** |
95 | * v4l2_event_queue - Queue events to video device. |
96 | * |
97 | * @vdev: pointer to &struct video_device |
98 | * @ev: pointer to &struct v4l2_event |
99 | * |
100 | * The event will be queued for all &struct v4l2_fh file handlers. |
101 | * |
102 | * .. note:: |
103 | * The driver's only responsibility is to fill in the type and the data |
104 | * fields. The other fields will be filled in by V4L2. |
105 | */ |
106 | void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev); |
107 | |
108 | /** |
109 | * v4l2_event_queue_fh - Queue events to video device. |
110 | * |
111 | * @fh: pointer to &struct v4l2_fh |
112 | * @ev: pointer to &struct v4l2_event |
113 | * |
114 | * |
115 | * The event will be queued only for the specified &struct v4l2_fh file handler. |
116 | * |
117 | * .. note:: |
118 | * The driver's only responsibility is to fill in the type and the data |
119 | * fields. The other fields will be filled in by V4L2. |
120 | */ |
121 | void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev); |
122 | |
123 | /** |
124 | * v4l2_event_wake_all - Wake all filehandles. |
125 | * |
126 | * Used when unregistering a video device. |
127 | * |
128 | * @vdev: pointer to &struct video_device |
129 | */ |
130 | void v4l2_event_wake_all(struct video_device *vdev); |
131 | |
132 | /** |
133 | * v4l2_event_pending - Check if an event is available |
134 | * |
135 | * @fh: pointer to &struct v4l2_fh |
136 | * |
137 | * Returns the number of pending events. |
138 | */ |
139 | int v4l2_event_pending(struct v4l2_fh *fh); |
140 | |
141 | /** |
142 | * v4l2_event_subscribe - Subscribes to an event |
143 | * |
144 | * @fh: pointer to &struct v4l2_fh |
145 | * @sub: pointer to &struct v4l2_event_subscription |
146 | * @elems: size of the events queue |
147 | * @ops: pointer to &v4l2_subscribed_event_ops |
148 | * |
149 | * .. note:: |
150 | * |
151 | * if @elems is zero, the framework will fill in a default value, |
152 | * with is currently 1 element. |
153 | */ |
154 | int v4l2_event_subscribe(struct v4l2_fh *fh, |
155 | const struct v4l2_event_subscription *sub, |
156 | unsigned int elems, |
157 | const struct v4l2_subscribed_event_ops *ops); |
158 | /** |
159 | * v4l2_event_unsubscribe - Unsubscribes to an event |
160 | * |
161 | * @fh: pointer to &struct v4l2_fh |
162 | * @sub: pointer to &struct v4l2_event_subscription |
163 | */ |
164 | int v4l2_event_unsubscribe(struct v4l2_fh *fh, |
165 | const struct v4l2_event_subscription *sub); |
166 | /** |
167 | * v4l2_event_unsubscribe_all - Unsubscribes to all events |
168 | * |
169 | * @fh: pointer to &struct v4l2_fh |
170 | */ |
171 | void v4l2_event_unsubscribe_all(struct v4l2_fh *fh); |
172 | |
173 | /** |
174 | * v4l2_event_subdev_unsubscribe - Subdev variant of v4l2_event_unsubscribe() |
175 | * |
176 | * @sd: pointer to &struct v4l2_subdev |
177 | * @fh: pointer to &struct v4l2_fh |
178 | * @sub: pointer to &struct v4l2_event_subscription |
179 | * |
180 | * .. note:: |
181 | * |
182 | * This function should be used for the &struct v4l2_subdev_core_ops |
183 | * %unsubscribe_event field. |
184 | */ |
185 | int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, |
186 | struct v4l2_fh *fh, |
187 | struct v4l2_event_subscription *sub); |
188 | /** |
189 | * v4l2_src_change_event_subscribe - helper function that calls |
190 | * v4l2_event_subscribe() if the event is %V4L2_EVENT_SOURCE_CHANGE. |
191 | * |
192 | * @fh: pointer to struct v4l2_fh |
193 | * @sub: pointer to &struct v4l2_event_subscription |
194 | */ |
195 | int v4l2_src_change_event_subscribe(struct v4l2_fh *fh, |
196 | const struct v4l2_event_subscription *sub); |
197 | /** |
198 | * v4l2_src_change_event_subdev_subscribe - Variant of v4l2_event_subscribe(), |
199 | * meant to subscribe only events of the type %V4L2_EVENT_SOURCE_CHANGE. |
200 | * |
201 | * @sd: pointer to &struct v4l2_subdev |
202 | * @fh: pointer to &struct v4l2_fh |
203 | * @sub: pointer to &struct v4l2_event_subscription |
204 | */ |
205 | int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd, |
206 | struct v4l2_fh *fh, |
207 | struct v4l2_event_subscription *sub); |
208 | #endif /* V4L2_EVENT_H */ |
209 | |