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