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