| 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_pending - Check if an event is available |
| 125 | * |
| 126 | * @fh: pointer to &struct v4l2_fh |
| 127 | * |
| 128 | * Returns the number of pending events. |
| 129 | */ |
| 130 | int v4l2_event_pending(struct v4l2_fh *fh); |
| 131 | |
| 132 | /** |
| 133 | * v4l2_event_subscribe - Subscribes to an event |
| 134 | * |
| 135 | * @fh: pointer to &struct v4l2_fh |
| 136 | * @sub: pointer to &struct v4l2_event_subscription |
| 137 | * @elems: size of the events queue |
| 138 | * @ops: pointer to &v4l2_subscribed_event_ops |
| 139 | * |
| 140 | * .. note:: |
| 141 | * |
| 142 | * if @elems is zero, the framework will fill in a default value, |
| 143 | * with is currently 1 element. |
| 144 | */ |
| 145 | int v4l2_event_subscribe(struct v4l2_fh *fh, |
| 146 | const struct v4l2_event_subscription *sub, |
| 147 | unsigned int elems, |
| 148 | const struct v4l2_subscribed_event_ops *ops); |
| 149 | /** |
| 150 | * v4l2_event_unsubscribe - Unsubscribes to an event |
| 151 | * |
| 152 | * @fh: pointer to &struct v4l2_fh |
| 153 | * @sub: pointer to &struct v4l2_event_subscription |
| 154 | */ |
| 155 | int v4l2_event_unsubscribe(struct v4l2_fh *fh, |
| 156 | const struct v4l2_event_subscription *sub); |
| 157 | /** |
| 158 | * v4l2_event_unsubscribe_all - Unsubscribes to all events |
| 159 | * |
| 160 | * @fh: pointer to &struct v4l2_fh |
| 161 | */ |
| 162 | void v4l2_event_unsubscribe_all(struct v4l2_fh *fh); |
| 163 | |
| 164 | /** |
| 165 | * v4l2_event_subdev_unsubscribe - Subdev variant of v4l2_event_unsubscribe() |
| 166 | * |
| 167 | * @sd: pointer to &struct v4l2_subdev |
| 168 | * @fh: pointer to &struct v4l2_fh |
| 169 | * @sub: pointer to &struct v4l2_event_subscription |
| 170 | * |
| 171 | * .. note:: |
| 172 | * |
| 173 | * This function should be used for the &struct v4l2_subdev_core_ops |
| 174 | * %unsubscribe_event field. |
| 175 | */ |
| 176 | int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, |
| 177 | struct v4l2_fh *fh, |
| 178 | struct v4l2_event_subscription *sub); |
| 179 | /** |
| 180 | * v4l2_src_change_event_subscribe - helper function that calls |
| 181 | * v4l2_event_subscribe() if the event is %V4L2_EVENT_SOURCE_CHANGE. |
| 182 | * |
| 183 | * @fh: pointer to struct v4l2_fh |
| 184 | * @sub: pointer to &struct v4l2_event_subscription |
| 185 | */ |
| 186 | int v4l2_src_change_event_subscribe(struct v4l2_fh *fh, |
| 187 | const struct v4l2_event_subscription *sub); |
| 188 | /** |
| 189 | * v4l2_src_change_event_subdev_subscribe - Variant of v4l2_event_subscribe(), |
| 190 | * meant to subscribe only events of the type %V4L2_EVENT_SOURCE_CHANGE. |
| 191 | * |
| 192 | * @sd: pointer to &struct v4l2_subdev |
| 193 | * @fh: pointer to &struct v4l2_fh |
| 194 | * @sub: pointer to &struct v4l2_event_subscription |
| 195 | */ |
| 196 | int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd, |
| 197 | struct v4l2_fh *fh, |
| 198 | struct v4l2_event_subscription *sub); |
| 199 | #endif /* V4L2_EVENT_H */ |