[PATCH v2 1/2] dt-bindings: drm/bridge: anx7625: MIPI to DP transmitter binding

[Laurent Pinchart]

Hi Xin Ji,

Thank you for the patch.

On Wed, Oct 09, 2019 at 09:27:07AM +0000, Xin Ji wrote:
> The ANX7625 is an ultra-low power 4K Mobile HD Transmitter designed
> for portable device. It converts MIPI to DisplayPort 1.3 4K.
> 
> You can add support to your board with binding.
> 
> Example:
> 	anx_bridge: anx7625 at 58 {
> 		compatible = "analogix,anx7625";
> 		reg = <0x58>;
> 		enable-gpios = <&gpio0 45 GPIO_ACTIVE_LOW>;
> 		reset-gpios = <&gpio0 73 GPIO_ACTIVE_LOW>;
> 		status = "okay";
> 		port at 0 {
> 			reg = <0>;
> 			anx7625_1_in: endpoint {
> 				remote-endpoint = <&mipi_dsi_bridge_1>;
> 			};
> 		};
> 	};
> 
> Signed-off-by: Xin Ji <xji at analogixsemi.com>
> ---
>  .../bindings/display/bridge/anx7625.yaml           | 79 ++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7625.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/anx7625.yaml b/Documentation/devicetree/bindings/display/bridge/anx7625.yaml
> new file mode 100644
> index 0000000..0ef6271
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/anx7625.yaml
> @@ -0,0 +1,79 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2019 Analogix Semiconductor, Inc.
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/display/bridge/anx7625.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Analogix ANX7625 SlimPort (4K Mobile HD Transmitter)
> +
> +maintainers:
> +  - Xin Ji <xji at analogixsemi.com>
> +
> +description: |
> +  The ANX7625 is an ultra-low power 4K Mobile HD Transmitter
> +  designed for portable devices.
> +
> +properties:
> +  compatible:
> +    items:
> +      - const: analogix,anx7625
> +
> +  reg:
> +    maxItems: 1
> +
> +  hpd-gpios:
> +    description: used for HPD interrupt
> +    maxItems: 1

You explained in your reply to v1 review that this describes the
interrupt generated by the ANX7625. It should be replaced by an
interrupts property.

> +
> +  enable-gpios:
> +    description: used for power on chip control
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description: used for reset chip control
> +    maxItems: 1

Could you please mention the exact name of the corresponding pins on the
chip for enable and reset ?

> +
> +  port at 0:
> +    type: object
> +    description:
> +      A port node pointing to MIPI DSI host port node.
> +
> +  port at 1:
> +    type: object
> +    description:
> +      A port node pointing to MIPI DPI host port node.
> +
> +  port at 2:
> +    type: object
> +    description:
> +      A port node pointing to external connector port node.
> +
> +  port at 3:
> +    type: object
> +    description:
> +      A port node pointing to internal panel port node.
> +
> +  port at 4:
> +    type: object
> +    description:
> +      A port node pointing to normal eDP port node.

I don't think three output ports is correct. Ports 3 and 4 are really
the same. I'm even unsure about port 2 and 3, someone with better
knowledge of USB-C and DisplayPort would be in a better position to
comment.

> +

You're missing the #address-cells and #size-cells properties required
for the ports. As the device is an I2C device we're lucky that the
parent will specify compatible address and size cells numbers, but I'm
not sure we should rely on that luck.

Rob, how does yaml schema handle this ?

> +required:
> +  - compatible
> +  - reg
> +  - port at 0 | port at 1
> +
> +example:
> +  - |
> +    anx_bridge: anx7625 at 58 {

The node name should describe the device's function. How about
encoder at 58 ?

> +        compatible = "analogix,anx7625";
> +        reg = <0x58>;
> +        status = "okay";
> +        port at 0 {
> +          reg = <0>;
> +          anx7625_1_in: endpoint {
> +            remote-endpoint = <&mipi_dsi_bridge_1>;
> +          };
> +        };
> +    };

-- 
Regards,

Laurent Pinchart