[media] v4l2-ctrls: simplify event subscription
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index 5f31666..d084cea 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -1013,6 +1013,7 @@
insertion is an O(1) operation. */
if (list_empty(&hdl->ctrl_refs) || id > node2id(hdl->ctrl_refs.prev)) {
list_add_tail(&new_ref->node, &hdl->ctrl_refs);
+ hdl->nr_of_refs++;
goto insert_in_hash;
}
@@ -2061,3 +2062,22 @@
v4l2_ctrl_unlock(ctrl);
}
EXPORT_SYMBOL(v4l2_ctrl_del_fh);
+
+int v4l2_ctrl_subscribe_fh(struct v4l2_fh *fh,
+ struct v4l2_event_subscription *sub, unsigned n)
+{
+ struct v4l2_ctrl_handler *hdl = fh->ctrl_handler;
+ int ret = 0;
+
+ if (!fh->events)
+ ret = v4l2_event_init(fh);
+ if (!ret) {
+ if (hdl->nr_of_refs * 2 > n)
+ n = hdl->nr_of_refs * 2;
+ ret = v4l2_event_alloc(fh, n);
+ }
+ if (!ret)
+ ret = v4l2_event_subscribe(fh, sub);
+ return ret;
+}
+EXPORT_SYMBOL(v4l2_ctrl_subscribe_fh);