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[]; 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
