media: video-mux: Skip dangling endpoints

[ Upstream commit 95778c2 ]

i.MX6 device tree include files contain dangling endpoints for the
board device tree writers' convenience. These are still included in
many existing device trees.
Treat dangling endpoints as non-existent to support them.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Fixes: 612b385 ("media: video-mux: Create media links in bound notifier")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/media/platform/video-mux.c

@@ -362,14 +362,22 @@ static int video_mux_async_register(struct video_mux *vmux,
 
 	for (i = 0; i < num_input_pads; i++) {
 		struct v4l2_async_subdev *asd;
-		struct fwnode_handle *ep;
+		struct fwnode_handle *ep, *remote_ep;
 
 		ep = fwnode_graph_get_endpoint_by_id(
 			dev_fwnode(vmux->subdev.dev), i, 0,
 			FWNODE_GRAPH_ENDPOINT_NEXT);
 		if (!ep)
 			continue;
 
+		/* Skip dangling endpoints for backwards compatibility */
+		remote_ep = fwnode_graph_get_remote_endpoint(ep);
+		if (!remote_ep) {
+			fwnode_handle_put(ep);
+			continue;
+		}
+		fwnode_handle_put(remote_ep);
+
 		asd = v4l2_async_notifier_add_fwnode_remote_subdev(
 			&vmux->notifier, ep, sizeof(*asd));