Re: [PATCH v2 2/2] dt-bindings: drm/bridge: Document Cadence DSI bridge bindings

Hi,

Just spotted this thread.

On 06.06.2017 14:58, Tomi Valkeinen wrote:

On 06/06/17 15:48, Boris Brezillon wrote:

quoted

Okay. Thanks for the clarification. Can you confirm that this version
is correct?

 	dsi@xxx {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
 		ports {
 			#address-cells = <1>;
 			#size-cells = <0>;
			dpi_in: port@0 {
 				reg = <0>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 
 				endpoint@0 {
 					remote-endpoint = <&dpi_out>;
 				};
 			};
 
 			dsi_out: port@1 {
 				reg = <1>;
				#address-cells = <1>;
 				#size-cells = <0>;
 
 				dsi_out_vc0: endpoint@0 {
					reg = <0>;
 					remote-endpoint = <&dsi_panel0_in>;
				};

 				dsi_out_vc1: endpoint@1 {
					reg = <1>;
 					remote-endpoint = <&dsi_panel1_in>;
 				};
 			};
 		};
 
 		panel@0 {
 			compatible = "...";
 			reg = <0>;
 			#address-cells = <1>;
 			#size-cells = <0>;
 
 			port@0 {
 				#address-cells = <1>;
 		                #size-cells = <0>;
 				reg = <0>;
 
 				dsi_panel0_in: endpoint@0 {
					reg = <0>;
 					remote-endpoint = <&dsi_out_vc0>;
 				};
 			};
 		};
 
 		panel@1 {
 			compatible = "...";
 			reg = <1>;
 			#address-cells = <1>;
 			#size-cells = <0>;
 
 			port@0 {
 				#address-cells = <1>;
 		                #size-cells = <0>;
 				reg = <0>;
 
 				dsi_panel1_in: endpoint@0 {
					reg = <0>;
 					remote-endpoint = <&dsi_out_vc1>;
 				};
 			};
 		};
 	};

Looks correct to me. I think it can be a bit shorter though:

- You don't need #address-cells and #size-cells for all. I think those
are inherited from the parent.
- If there's just one port and one endpoint, you can leave the 'reg'
out, as it's considered to be 0 by default.

So for the panel, you can have just:

port {
	dsi_panel1_in: endpoint {
		remote-endpoint = <&dsi_out_vc1>;
	};
};

In case DSI bus is used to both control and sending video signal you can
skip video links from dsi-host to dsi-child, so nodes can look like:


 	dsi@xxx {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
 		ports {
 			#address-cells = <1>;
 			#size-cells = <0>;
			dpi_in: port@0 {
 				reg = <0>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 
 				endpoint@0 {
 					remote-endpoint = <&dpi_out>;
 				};
 			};
 
 		};
 
 		panel@0 {
 			compatible = "...";
 			reg = <0>;
 		};
 
 		panel@1 {
 			compatible = "...";
 			reg = <1>;
 		};
 	};



Regards
Andrzej

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