Re: [PATCH v2 2/8] dt-bindings: display: add verisilicon,dc

[Icenowy Zheng <uwu@icenowy.me>]

在 2025-09-22星期一的 15:43 -0500，Rob Herring写道：
> On Sun, Sep 21, 2025 at 04:34:40PM +0800, Icenowy Zheng wrote:
> > 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>
> > ---
> > 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      | 127
> > ++++++++++++++++++
> >  1 file changed, 127 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..07fedc4c7cc13
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> > @@ -0,0 +1,127 @@
> > +# 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:
> > +    const: verisilicon,dc
> 
> This needs an SoC specific compatible. Generally licensed IP
> compatibles 
> are useless because the specs aren't public and there's always 
> integration quirks.

This mimics the GPU IPs by the same vendor, see gpu/vivante,gc.yaml ,
which contain the exact same set of identification registers (including
a "customer id" one that can differienate the same configured IP on
StarFive JH7110 and T-Head TH1520).

If we can get vivante,gc to work w/o SoC specific compatible, then we
should be able to get verisilicon,dc to work too.

> 
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    minItems: 4
> > +    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:
> > +    minItems: 4
> > +    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
> > +          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 and used. Follow the same endpoint addressing
> > +          rule with the first port.
> > +
> > +    required:
> > +      - port@0
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - clocks
> > +  - clock-names
> > +  - ports
> > +
> > +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 = "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>;
> > +            };
> > +          };
> > +        };
> > +      };
> > +    };
> > -- 
> > 2.51.0
> >