Re: [PATCH v5 1/4] dt-bindings: media: Document bindings for DW MIPI CSI-2 Host

[Rob Herring <robh@kernel.org>]

On Fri, Dec 16, 2022 at 04:37:14PM +0200, Eugen Hristev wrote:
> Add bindings for Synopsys DesignWare MIPI CSI-2 host.
> 
> Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
> [eugen.hristev@microchip.com: reworked binding, converted to yaml]
> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> ---
>  .../bindings/media/snps,dw-csi.yaml           | 149 ++++++++++++++++++
>  1 file changed, 149 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/snps,dw-csi.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/snps,dw-csi.yaml b/Documentation/devicetree/bindings/media/snps,dw-csi.yaml
> new file mode 100644
> index 000000000000..439eadc8e517
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/snps,dw-csi.yaml
> @@ -0,0 +1,149 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/snps,dw-csi.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Synopsys DesignWare CSI-2 Host controller (csi2host)
> +
> +maintainers:
> +  - Eugen Hristev <eugen.hristev@microchip.com>
> +
> +description:
> +  CSI2HOST is used to receive image coming from an MIPI CSI-2 compatible
> +  camera. It will convert the incoming CSI-2 stream into a dedicated
> +  interface called the Synopsys IDI (Image Data Interface).
> +  This interface is a 32-bit SoC internal only, and can be assimilated
> +  with a CSI-2 interface.
> +
> +properties:
> +  compatible:
> +    const: snps,dw-csi

This needs an SoC specific compatible.

> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 2
> +
> +  clock-names:
> +    description:
> +      CSI2HOST can have two clocks connected. One clock is the
> +      peripheral clock for the inside functionality of the hardware block.
> +      This is named 'perclk'. The second clock can be the phy clock,
> +      which is used to clock the phy via an internal link.
> +      This clock is named 'phyclk', phy clock.

The schema says most of this, don't repeat it in freeform text. If you 
want a description of each clock, that goes 'clocks' like this:

items:
  - description: ...
  - description: ...

> +    items:
> +      - const: perclk
> +      - const: phyclk
> +
> +  phys:
> +    maxItems: 1
> +    description: MIPI D-PHY
> +
> +  phy-names:
> +    items:
> +      - const: dphy
> +
> +  resets:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description:
> +          Input port node, single endpoint describing the input port.
> +
> +        properties:
> +          endpoint:
> +            $ref: video-interfaces.yaml#
> +            unevaluatedProperties: false
> +            description: Endpoint connected to input device

Don't need generic descriptions. Only the port nodes need to define what 
they are.

> +
> +            properties:
> +              bus-type:
> +                const: 4
> +
> +              data-lanes:
> +                minItems: 1
> +                maxItems: 4
> +                items:
> +                  maximum: 4
> +
> +              clock-lanes:
> +                maxItems: 1
> +
> +              remote-endpoint: true

Don't need to list this.

> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description:
> +          Output port node, single endpoint describing the output port.
> +
> +        properties:
> +          endpoint:
> +            unevaluatedProperties: false
> +            $ref: video-interfaces.yaml#
> +            description: Endpoint connected to output device
> +
> +            properties:
> +              bus-type:
> +                const: 4
> +
> +              remote-endpoint: true

Ditto.

> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - ports
> +
> +examples:
> +  - |
> +    csi2: csi2@3000 {
> +        compatible = "snps,dw-csi";
> +        reg = <0x03000 0x7FF>;
> +        phys = <&mipi_dphy_rx>;
> +        phy-names = "dphy";
> +        resets = <&dw_rst 1>;
> +        interrupts = <2>;
> +
> +        ports {
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            port@0 {
> +                reg = <0>;
> +
> +                csi_ep1: endpoint {
> +                    bus-type = <4>; /* MIPI CSI2 D-PHY */
> +                    remote-endpoint = <&camera_1>;
> +                    data-lanes = <1 2>;
> +                    clock-lanes = <0>;
> +                };
> +            };
> +
> +            port@1 {
> +                reg = <1>;
> +
> +                csi_ep2: endpoint {
> +                    remote-endpoint = <&idi_receiver>;
> +                    bus-type = <4>;
> +                };
> +            };
> +        };
> +    };
> +
> +...
> -- 
> 2.25.1
> 
>