Re: [PATCHv2] dt-bindings: dp-connector: add binding for DisplayPort connector

[Rob Herring <robh@kernel.org>]

On Thu, Sep 17, 2020 at 08:52:10AM +0300, Tomi Valkeinen wrote:
> Add binding for DisplayPort connector. A few notes:
> 
> * Similar to hdmi-connector, it has hpd-gpios as an optional property,
>   as the HPD could also be handled by, e.g., the DP bridge.
> 
> * dp-pwr-supply, which provides 3.3V on DP_PWR pin, is optional, as it
>   is not strictly required: standard DP cables do not even have the pin
>   connected.
> 
> * Connector type. Full size and mini connectors are identical except for
>   the connector size and form, so I believe there is no functional need
>   for this property. But similar to 'label' property, it might be used
>   to present information about the connector to the userspace.
> 
> * No eDP. There's really no "eDP connector", as it's always a custom
>   made connection between the DP and the DP panel. So possibly there is
>   no need for edp-connector binding, but even if there is, I don't want
>   to guess what it could look like, and could it be part of the
>   dp-connector binding.

I don't think that's true. Do an image search for 'edp pinout'. AFAICT, 
there's 2 lane 30 pin and 4 lane 40 pin. One image says 'Table 5-3 in 
eDP v1.2'. Of course, I'm sure there's custom ones too. From a binding 
perspective, we probably don't care about the differences, but just need 
to be able to describe HPD, backlight power, enable, and pwm, and LCD 
power.

That said, it's fine to not handle eDP here.

> 
> * No DP++. I'm not familiar with DP++, but I think it's all handled by
>   the DP bridge, and does not need any new properties to the dp-connector.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
> 
> Changes in v2: Add connector type.
> 
> 
>  .../display/connector/dp-connector.yaml       | 55 +++++++++++++++++++
>  1 file changed, 55 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/connector/dp-connector.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/connector/dp-connector.yaml b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
> new file mode 100644
> index 000000000000..b5fc3e52899e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/connector/dp-connector.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: DisplayPort Connector
> +
> +maintainers:
> +  - Tomi Valkeinen <tomi.valkeinen@ti.com>
> +
> +properties:
> +  compatible:
> +    const: dp-connector
> +
> +  label: true
> +
> +  type:
> +    enum:
> +      - full-size
> +      - mini
> +
> +  hpd-gpios:
> +    description: A GPIO line connected to HPD
> +    maxItems: 1
> +
> +  dp-pwr-supply:
> +    description: Power supply for the DP_PWR pin
> +    maxItems: 1
> +
> +  port:
> +    description: Connection to controller providing DP signals
> +
> +required:
> +  - compatible
> +  - type
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    connector {
> +        compatible = "dp-connector";
> +        label = "dp0";
> +        type = "full-size";
> +
> +        port {
> +            dp_connector_in: endpoint {
> +                remote-endpoint = <&dp_out>;
> +            };
> +        };
> +    };
> +
> +...
> -- 
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