media: v4l2-event: keep track of the timestamp in ns

Internally use ktime_get_ns() to get the timestamp of the event.
Only convert to timespec when interfacing with userspace.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/v4l2-core/v4l2-event.c

@@ -52,6 +52,7 @@ static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
 
 	kev->event.pending = fh->navailable;
 	*event = kev->event;
+	event->timestamp = ns_to_timespec(kev->ts);
 	kev->sev->first = sev_pos(kev->sev, 1);
 	kev->sev->in_use--;
 
@@ -103,8 +104,8 @@ static struct v4l2_subscribed_event *v4l2_event_subscribed(
 	return NULL;
 }
 
-static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev,
-		const struct timespec *ts)
+static void __v4l2_event_queue_fh(struct v4l2_fh *fh,
+				  const struct v4l2_event *ev, u64 ts)
 {
 	struct v4l2_subscribed_event *sev;
 	struct v4l2_kevent *kev;
@@ -144,7 +145,7 @@ static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *e
 	if (copy_payload)
 		kev->event.u = ev->u;
 	kev->event.id = ev->id;
-	kev->event.timestamp = *ts;
+	kev->ts = ts;
 	kev->event.sequence = fh->sequence;
 	sev->in_use++;
 	list_add_tail(&kev->list, &fh->available);
@@ -158,17 +159,17 @@ void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)
 {
 	struct v4l2_fh *fh;
 	unsigned long flags;
-	struct timespec timestamp;
+	u64 ts;
 
 	if (vdev == NULL)
 		return;
 
-	ktime_get_ts(&timestamp);
+	ts = ktime_get_ns();
 
 	spin_lock_irqsave(&vdev->fh_lock, flags);
 
 	list_for_each_entry(fh, &vdev->fh_list, list)
-		__v4l2_event_queue_fh(fh, ev, &timestamp);
+		__v4l2_event_queue_fh(fh, ev, ts);
 
 	spin_unlock_irqrestore(&vdev->fh_lock, flags);
 }
@@ -177,12 +178,10 @@ EXPORT_SYMBOL_GPL(v4l2_event_queue);
 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)
 {
 	unsigned long flags;
-	struct timespec timestamp;
-
-	ktime_get_ts(&timestamp);
+	u64 ts = ktime_get_ns();
 
 	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
-	__v4l2_event_queue_fh(fh, ev, &timestamp);
+	__v4l2_event_queue_fh(fh, ev, ts);
 	spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
 }
 EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);

include/media/v4l2-event.h

@@ -34,11 +34,13 @@ struct video_device;
  * @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;
 };
 
 /**