Re: [PATCH v4 2/9] dt-bindings: display: add verisilicon,dc

[Rob Herring <robh@kernel.org>]

On Thu, Dec 25, 2025 at 12:11:58AM +0800, Icenowy Zheng wrote:
> From: Icenowy Zheng <uwu@icenowy.me>
> 
> Verisilicon has a series of display controllers prefixed with DC and
> with self-identification facility like their GC series GPUs.
> 
> Add a device tree binding for it.
> 
> Depends on the specific DC model, it can have either one or two display
> outputs, and each display output could be set to DPI signal or "DP"
> signal (which seems to be some plain parallel bus to HDMI controllers).
> 
> Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
> Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
> ---
> Changes in v4:
> - Added a comment for "verisilicon,dc" that says the ID/revision is
>   discoverable via registers.
> - Removed clock minItems constraint w/o specific compatible strings.
> 
> Changes in v3:
> - Added SoC-specific compatible string, and arm the binding with clock /
>   port checking for the specific SoC (with a 2-output DC).
> 
> Changes in v2:
> - Fixed misspelt "versilicon" in title.
> - Moved minItems in clock properties to be earlier than items.
> - Re-aligned multi-line clocks and resets in example.
> 
>  .../bindings/display/verisilicon,dc.yaml      | 144 ++++++++++++++++++
>  1 file changed, 144 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> new file mode 100644
> index 0000000000000..fe64cc1466690
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> @@ -0,0 +1,144 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/verisilicon,dc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Verisilicon DC-series display controllers
> +
> +maintainers:
> +  - Icenowy Zheng <uwu@icenowy.me>
> +
> +properties:
> +  $nodename:
> +    pattern: "^display@[0-9a-f]+$"
> +
> +  compatible:
> +    items:
> +      - enum:
> +          - thead,th1520-dc8200
> +      - const: verisilicon,dc # DC IPs have discoverable ID/revision registers
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: DC Core clock
> +      - description: DMA AXI bus clock
> +      - description: Configuration AHB bus clock
> +      - description: Pixel clock of output 0
> +      - description: Pixel clock of output 1
> +
> +  clock-names:
> +    items:
> +      - const: core
> +      - const: axi
> +      - const: ahb
> +      - const: pix0
> +      - const: pix1
> +
> +  resets:
> +    items:
> +      - description: DC Core reset
> +      - description: DMA AXI bus reset
> +      - description: Configuration AHB bus reset
> +
> +  reset-names:
> +    items:
> +      - const: core
> +      - const: axi
> +      - const: ahb
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: The first output channel , endpoint 0 should be

No space before comma. Or perhaps should be a period instead.


> +          used for DPI format output and endpoint 1 should be used
> +          for DP format output.
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: The second output channel if the DC variant
> +          supports. Follow the same endpoint addressing rule with
> +          the first port.
> +
> +    required:
> +      - port@0
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - ports
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: thead,th1520-dc8200
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 5

That's already implicitly the min. Perhaps you wanted 'minItems: 4' on 
the clocks and clock-names definitions for versions with only 1 output?

> +        ports:
> +          required:
> +            - port@0
> +            - port@1

It is valid to omit these if the output is present, but unused.

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/clock/thead,th1520-clk-ap.h>
> +    #include <dt-bindings/reset/thead,th1520-reset.h>
> +    soc {
> +      #address-cells = <2>;
> +      #size-cells = <2>;
> +
> +      display@ffef600000 {
> +        compatible = "thead,th1520-dc8200", "verisilicon,dc";
> +        reg = <0xff 0xef600000 0x0 0x100000>;
> +        interrupts = <93 IRQ_TYPE_LEVEL_HIGH>;
> +        clocks = <&clk_vo CLK_DPU_CCLK>,
> +                 <&clk_vo CLK_DPU_ACLK>,
> +                 <&clk_vo CLK_DPU_HCLK>,
> +                 <&clk_vo CLK_DPU_PIXELCLK0>,
> +                 <&clk_vo CLK_DPU_PIXELCLK1>;
> +        clock-names = "core", "axi", "ahb", "pix0", "pix1";
> +        resets = <&rst TH1520_RESET_ID_DPU_CORE>,
> +                 <&rst TH1520_RESET_ID_DPU_AXI>,
> +                 <&rst TH1520_RESET_ID_DPU_AHB>;
> +        reset-names = "core", "axi", "ahb";
> +
> +        ports {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          port@0 {
> +            reg = <0>;
> +          };
> +
> +          port@1 {
> +            reg = <1>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            dpu_out_dp1: endpoint@1 {
> +              reg = <1>;
> +              remote-endpoint = <&hdmi_in>;
> +            };
> +          };
> +        };
> +      };
> +    };
> -- 
> 2.52.0
>