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Diffstat (limited to 'include/media/v4l2-event.h')
| -rw-r--r-- | include/media/v4l2-event.h | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h new file mode 100644 index 0000000000..4ffa914ade --- /dev/null +++ b/include/media/v4l2-event.h @@ -0,0 +1,208 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * v4l2-event.h + * + * V4L2 events. + * + * Copyright (C) 2009--2010 Nokia Corporation. + * + * Contact: Sakari Ailus <sakari.ailus@iki.fi> + */ + +#ifndef V4L2_EVENT_H +#define V4L2_EVENT_H + +#include <linux/types.h> +#include <linux/videodev2.h> +#include <linux/wait.h> + +struct v4l2_fh; +struct v4l2_subdev; +struct v4l2_subscribed_event; +struct video_device; + +/** + * struct v4l2_kevent - Internal kernel event struct. + * @list: List node for the v4l2_fh->available list. + * @sev: Pointer to parent v4l2_subscribed_event. + * @event: The event itself. + * @ts: The timestamp of the event. + */ +struct v4l2_kevent { + struct list_head list; + struct v4l2_subscribed_event *sev; + struct v4l2_event event; + u64 ts; +}; + +/** + * struct v4l2_subscribed_event_ops - Subscribed event operations. + * + * @add: Optional callback, called when a new listener is added + * @del: Optional callback, called when a listener stops listening + * @replace: Optional callback that can replace event 'old' with event 'new'. + * @merge: Optional callback that can merge event 'old' into event 'new'. + */ +struct v4l2_subscribed_event_ops { + int (*add)(struct v4l2_subscribed_event *sev, unsigned int elems); + void (*del)(struct v4l2_subscribed_event *sev); + void (*replace)(struct v4l2_event *old, const struct v4l2_event *new); + void (*merge)(const struct v4l2_event *old, struct v4l2_event *new); +}; + +/** + * struct v4l2_subscribed_event - Internal struct representing a subscribed + * event. + * + * @list: List node for the v4l2_fh->subscribed list. + * @type: Event type. + * @id: Associated object ID (e.g. control ID). 0 if there isn't any. + * @flags: Copy of v4l2_event_subscription->flags. + * @fh: Filehandle that subscribed to this event. + * @node: List node that hooks into the object's event list + * (if there is one). + * @ops: v4l2_subscribed_event_ops + * @elems: The number of elements in the events array. + * @first: The index of the events containing the oldest available event. + * @in_use: The number of queued events. + * @events: An array of @elems events. + */ +struct v4l2_subscribed_event { + struct list_head list; + u32 type; + u32 id; + u32 flags; + struct v4l2_fh *fh; + struct list_head node; + const struct v4l2_subscribed_event_ops *ops; + unsigned int elems; + unsigned int first; + unsigned int in_use; + struct v4l2_kevent events[]; +}; + +/** + * v4l2_event_dequeue - Dequeue events from video device. + * + * @fh: pointer to struct v4l2_fh + * @event: pointer to struct v4l2_event + * @nonblocking: if not zero, waits for an event to arrive + */ +int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, + int nonblocking); + +/** + * v4l2_event_queue - Queue events to video device. + * + * @vdev: pointer to &struct video_device + * @ev: pointer to &struct v4l2_event + * + * The event will be queued for all &struct v4l2_fh file handlers. + * + * .. note:: + * The driver's only responsibility is to fill in the type and the data + * fields. The other fields will be filled in by V4L2. + */ +void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev); + +/** + * v4l2_event_queue_fh - Queue events to video device. + * + * @fh: pointer to &struct v4l2_fh + * @ev: pointer to &struct v4l2_event + * + * + * The event will be queued only for the specified &struct v4l2_fh file handler. + * + * .. note:: + * The driver's only responsibility is to fill in the type and the data + * fields. The other fields will be filled in by V4L2. + */ +void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev); + +/** + * v4l2_event_wake_all - Wake all filehandles. + * + * Used when unregistering a video device. + * + * @vdev: pointer to &struct video_device + */ +void v4l2_event_wake_all(struct video_device *vdev); + +/** + * v4l2_event_pending - Check if an event is available + * + * @fh: pointer to &struct v4l2_fh + * + * Returns the number of pending events. + */ +int v4l2_event_pending(struct v4l2_fh *fh); + +/** + * v4l2_event_subscribe - Subscribes to an event + * + * @fh: pointer to &struct v4l2_fh + * @sub: pointer to &struct v4l2_event_subscription + * @elems: size of the events queue + * @ops: pointer to &v4l2_subscribed_event_ops + * + * .. note:: + * + * if @elems is zero, the framework will fill in a default value, + * with is currently 1 element. + */ +int v4l2_event_subscribe(struct v4l2_fh *fh, + const struct v4l2_event_subscription *sub, + unsigned int elems, + const struct v4l2_subscribed_event_ops *ops); +/** + * v4l2_event_unsubscribe - Unsubscribes to an event + * + * @fh: pointer to &struct v4l2_fh + * @sub: pointer to &struct v4l2_event_subscription + */ +int v4l2_event_unsubscribe(struct v4l2_fh *fh, + const struct v4l2_event_subscription *sub); +/** + * v4l2_event_unsubscribe_all - Unsubscribes to all events + * + * @fh: pointer to &struct v4l2_fh + */ +void v4l2_event_unsubscribe_all(struct v4l2_fh *fh); + +/** + * v4l2_event_subdev_unsubscribe - Subdev variant of v4l2_event_unsubscribe() + * + * @sd: pointer to &struct v4l2_subdev + * @fh: pointer to &struct v4l2_fh + * @sub: pointer to &struct v4l2_event_subscription + * + * .. note:: + * + * This function should be used for the &struct v4l2_subdev_core_ops + * %unsubscribe_event field. + */ +int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, + struct v4l2_fh *fh, + struct v4l2_event_subscription *sub); +/** + * v4l2_src_change_event_subscribe - helper function that calls + * v4l2_event_subscribe() if the event is %V4L2_EVENT_SOURCE_CHANGE. + * + * @fh: pointer to struct v4l2_fh + * @sub: pointer to &struct v4l2_event_subscription + */ +int v4l2_src_change_event_subscribe(struct v4l2_fh *fh, + const struct v4l2_event_subscription *sub); +/** + * v4l2_src_change_event_subdev_subscribe - Variant of v4l2_event_subscribe(), + * meant to subscribe only events of the type %V4L2_EVENT_SOURCE_CHANGE. + * + * @sd: pointer to &struct v4l2_subdev + * @fh: pointer to &struct v4l2_fh + * @sub: pointer to &struct v4l2_event_subscription + */ +int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd, + struct v4l2_fh *fh, + struct v4l2_event_subscription *sub); +#endif /* V4L2_EVENT_H */ |