[PATCH v2 7/7] V4L: Events: Support all events

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>]

Add support for subscribing all events with a special id V4L2_EVENT_ALL. If
V4L2_EVENT_ALL is subscribed, no other events may be subscribed. Otherwise
V4L2_EVENT_ALL is considered just as any other event.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx>
---
 drivers/media/video/v4l2-event.c |   13 ++++++++++++-
 include/linux/videodev2.h        |    1 +
 2 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c
index cd744d0..131bab7 100644
--- a/drivers/media/video/v4l2-event.c
+++ b/drivers/media/video/v4l2-event.c
@@ -133,6 +133,14 @@ static struct v4l2_subscribed_event *__v4l2_event_subscribed(
 	struct v4l2_events *events = fh->events;
 	struct v4l2_subscribed_event *sev;
 
+	if (list_empty(&events->subscribed))
+		return NULL;
+
+	sev = list_entry(events->subscribed.next,
+			 struct v4l2_subscribed_event, list);
+	if (sev->type == V4L2_EVENT_ALL)
+		return sev;
+
 	list_for_each_entry(sev, &events->subscribed, list) {
 		if (sev->type == type)
 			return sev;
@@ -212,6 +220,8 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
 	/* Allow subscribing to valid events only. */
 	if (sub->type < V4L2_EVENT_PRIVATE_START)
 		switch (sub->type) {
+		case V4L2_EVENT_ALL:
+			break;
 		default:
 			return -EINVAL;
 		}
@@ -252,7 +262,8 @@ int v4l2_event_unsubscribe(struct v4l2_fh *fh,
 
 	sev = __v4l2_event_subscribed(fh, sub->type);
 
-	if (sev == NULL) {
+	if (sev == NULL ||
+	    (sub->type != V4L2_EVENT_ALL && sev->type == V4L2_EVENT_ALL)) {
 		spin_unlock_irqrestore(&fh->vdev->fhs.lock, flags);
 		return -EINVAL;
 	}
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index a19ae89..9ae9a1c 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -1553,6 +1553,7 @@ struct v4l2_event_subscription {
 	__u32		reserved[7];
 };
 
+#define V4L2_EVENT_ALL				0
 #define V4L2_EVENT_PRIVATE_START		0x08000000
 
 /*
-- 
1.5.6.5

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