media: dt-bindings: tvp5150: add optional sdtv standards documentation

Document the optional binding to limit the possible sdtv standards on the
input connectors.
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/devicetree/bindings/media/i2c/tvp5150.txt

@@ -49,13 +49,22 @@ Required Endpoint Properties for parallel synchronization on output port:
 Note: Do not specify any of these properties if you want to use the embedded
       BT.656 synchronization.
 
+Optional Connector Properties:
+==============================
+
+- sdtv-standards: Set the possible signals to which the hardware tries to lock
+                  instead of using the autodetection mechnism. Please look at
+                  [1] for more information.
+
 [1] Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt.
 
 Example - three input sources:
+#include <dt-bindings/display/sdtv-standards.h>
 
 comp_connector_0 {
 	compatible = "composite-video-connector";
 	label = "Composite0";
+	sdtv-standards = <SDTV_STD_PAL_M>; /* limit to pal-m signals */
 
 	port {
 		composite0_to_tvp5150: endpoint {
@@ -67,6 +76,7 @@ comp_connector_0 {
 comp_connector_1 {
 	compatible = "composite-video-connector";
 	label = "Composite1";
+	sdtv-standards = <SDTV_STD_NTSC_M>; /* limit to ntsc-m signals */
 
 	port {
 		composite1_to_tvp5150: endpoint {