Re: [PATCH 2/3] dt-bindings: display: bridge: Add documentation for LT9611

Laurent Pinchart
2020-05-28T01:48:57Z

Hi Vinod,

Thank you for the patch.

On Wed, May 13, 2020 at 03:35:32PM +0530, Vinod Koul wrote:
> Lontium LT9611 is a DSI to HDMI bridge which supports 2 DSI ports
> and I2S port as input and one HDMI port as output
>
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> ---
> .../display/bridge/lontium,lt9611.yaml | 178 ++++++++++++++++++
> 1 file changed, 178 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml b/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml
> new file mode 100644
> index 000000000000..77ee8cc35cd8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml
> @@ -0,0 +1,178 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/lontium,lt9611.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Lontium LT9611 2 Port MIPI to HDMI Bridge
> +
> +maintainers:
> + - Vinod Koul <vkoul@kernel.org>
> +
> +description: |
> + The LT9611 is a bridge device which converts DSI to HDMI
> +
> +properties:
> + compatible:
> + enum:
> + - lontium,lt9611
> +
> + reg:
> + maxItems: 1
> + description: base I2C address of the device.
> +
> + "#sound-dai-cells":
> + const: 1
> +
> + interrupts:
> + maxItems: 1
> + description: interrupt line for the chip

I think you could drop the descriptions for the reg and interrupt
properties, they don't add much.

> +
> + reset-gpios:
> + maxItems: 1
> + description: GPIO connected to active high RESET pin.
> +
> + vdd-supply:
> + description: Regulator for 1.8V MIPI phy power.
> +
> + vcc-supply:
> + description: Regulator for 3.3V IO power.
> +
> + ports:
> + type: object
> +
> + properties:
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + port@0:
> + type: object
> + additionalProperties: false
> +
> + description: |
> + HDMI port for HDMI output

The usual practice is to have the input ports first, followed by the
output ports. Is there a reason not to follow that rule ?

> +
> + properties:
> + reg:
> + const: 0
> +
> + patternProperties:
> + endpoint:

If you want to use patternProperties, this should be

"^endpoint@[0-9]+$":

(including the quotes). Same below.

> + type: object
> + additionalProperties: false
> +
> + properties:
> + remote-endpoint: true

How about

remote-endpoint:
$ref: /schemas/types.yaml#/definitions/phandle

and the same below ?

You also need a reg property if multiple endpoints are present.

> +
> + required:
> + - reg
> +
> + port@1:
> + type: object
> + additionalProperties: false
> +
> + description: |
> + MIPI port-1 for MIPI input
> +
> + properties:
> + reg:
> + const: 1
> +
> + patternProperties:
> + endpoint:
> + type: object
> + additionalProperties: false
> +
> + properties:
> + remote-endpoint: true
> +
> + required:
> + - reg
> +
> + port@2:
> + type: object
> + additionalProperties: false
> +
> + description: |
> + MIPI port-2 for MIPI input

A description of how the two MIPI inputs differ would be useful. In
particular, are both mandatory, or is it valid to connect only one of
the two ? If using a single input is supported, can it be either, or
does it have to be the first one ? When using both inputs, what should
be connected to them ?

> +
> + properties:
> + reg:
> + const: 2
> +
> + patternProperties:
> + endpoint:
> + type: object
> + additionalProperties: false
> +
> + properties:
> + remote-endpoint: true
> +
> + required:
> + - reg
> +
> + required:
> + - "#address-cells"
> + - "#size-cells"
> + - port@0
> + - port@1
> +
> +required:
> + - compatible
> + - reg
> + - interrupts
> + - vdd-supply
> + - vcc-supply
> + - ports
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/gpio/gpio.h>
> + #include <dt-bindings/interrupt-controller/irq.h>
> +
> + i2c10 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + lt9611_codec: hdmi-bridge@3b {

Please drop unused labels.

> + compatible = "lontium,lt9611";
> + reg = <0x3b>;
> +
> + reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;
> + interrupts-extended = <&tlmm 84 IRQ_TYPE_EDGE_FALLING>;
> +
> + vdd-supply = <&lt9611_1v8>;
> + vcc-supply = <&lt9611_3v3>;
> +
> + ports {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + port@0 {
> + reg = <0>;
> + lt9611_out: endpoint {
> + remote-endpoint = <&hdmi_con>;
> + };
> + };
> +
> + port@1 {
> + reg = <1>;
> + lt9611_a: endpoint {
> + remote-endpoint = <&dsi0_out>;
> + };
> + };
> +
> + port@2 {
> + reg = <2>;
> + lt9611_b: endpoint {
> + remote-endpoint = <&dsi1_out>;
> + };
> + };
> + };
> + };
> + };

It's customary to end YAML schema files with ... on a separate line.

--
Regards,

Laurent Pinchart