/* 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[] __counted_by(elems); }; /** * 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 */
