Re: [PATCH] dt-bindings: clock: renesas: cpg-mssr: Convert to json-schema

[Stephen Boyd <sboyd@kernel.org>]

Quoting Geert Uytterhoeven (2020-02-24 07:26:40)
> diff --git a/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.yaml b/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.yaml
> new file mode 100644
> index 0000000000000000..dfbd1933f1bc56de
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.yaml
> @@ -0,0 +1,204 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/clock/renesas,cpg-mssr.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Renesas Clock Pulse Generator / Module Standby and Software Reset
> +
> +maintainers:
> +  - Geert Uytterhoeven <geert+renesas@glider.be>
> +
> +description: |
> +  On Renesas ARM SoCs (SH/R-Mobile, R-Car, RZ), the CPG (Clock Pulse Generator)
> +  and MSSR (Module Standby and Software Reset) blocks are intimately connected,
> +  and share the same register block.
> +
> +  They provide the following functionalities:
> +    - The CPG block generates various core clocks,
> +    - The MSSR block provides two functions:
> +        1. Module Standby, providing a Clock Domain to control the clock supply
> +           to individual SoC devices,
> +        2. Reset Control, to perform a software reset of individual SoC devices.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - renesas,r7s9210-cpg-mssr  # RZ/A2
> +      - renesas,r8a7743-cpg-mssr  # RZ/G1M
> +      - renesas,r8a7744-cpg-mssr  # RZ/G1N
> +      - renesas,r8a7745-cpg-mssr  # RZ/G1E
> +      - renesas,r8a77470-cpg-mssr # RZ/G1C
> +      - renesas,r8a774a1-cpg-mssr # RZ/G2M
> +      - renesas,r8a774b1-cpg-mssr # RZ/G2N
> +      - renesas,r8a774c0-cpg-mssr # RZ/G2E
> +      - renesas,r8a7790-cpg-mssr  # R-Car H2
> +      - renesas,r8a7791-cpg-mssr  # R-Car M2-W
> +      - renesas,r8a7792-cpg-mssr  # R-Car V2H
> +      - renesas,r8a7793-cpg-mssr  # R-Car M2-N
> +      - renesas,r8a7794-cpg-mssr  # R-Car E2
> +      - renesas,r8a7795-cpg-mssr  # R-Car H3
> +      - renesas,r8a7796-cpg-mssr  # R-Car M3-W
> +      - renesas,r8a77961-cpg-mssr # R-Car M3-W+
> +      - renesas,r8a77965-cpg-mssr # R-Car M3-N
> +      - renesas,r8a77970-cpg-mssr # R-Car V3M
> +      - renesas,r8a77980-cpg-mssr # R-Car V3H
> +      - renesas,r8a77990-cpg-mssr # R-Car E3
> +      - renesas,r8a77995-cpg-mssr # R-Car D3
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    minItems: 1
> +    maxItems: 2
> +
> +  clock-names:
> +    minItems: 1
> +    maxItems: 2

Do we need this here and also below? Why can't it just be below with the
more specific constraints?

> +
> +  '#clock-cells':
> +    description: |
> +      - For CPG core clocks, the two clock specifier cells must be "CPG_CORE"
> +        and a core clock reference, as defined in
> +        <dt-bindings/clock/*-cpg-mssr.h>
> +      - For module clocks, the two clock specifier cells must be "CPG_MOD" and
> +        a module number, as defined in the datasheet.
> +    const: 2
> +
> +  '#power-domain-cells':
> +    description:
> +      SoC devices that are part of the CPG/MSSR Clock Domain and can be
> +      power-managed through Module Standby should refer to the CPG device node
> +      in their "power-domains" property, as documented by the generic PM Domain
> +      bindings in Documentation/devicetree/bindings/power/power-domain.yaml.
> +    const: 0
> +
> +  '#reset-cells':
> +    description:
> +      The single reset specifier cell must be the module number, as defined in
> +      the datasheet.
> +    const: 1
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          items:
> +            enum:
> +              - renesas,r7s9210-cpg-mssr
> +              - renesas,r8a774c0-cpg-mssr
> +              - renesas,r8a7792-cpg-mssr
> +              - renesas,r8a77990-cpg-mssr
> +              - renesas,r8a77995-cpg-mssr
> +
> +    then:
> +      properties:
> +        clock:
> +          maxItems: 1
> +        clock-names:
> +          maxItems: 1
> +          items:
> +            - const: extal
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - renesas,r8a7743-cpg-mssr
> +              - renesas,r8a7744-cpg-mssr
> +              - renesas,r8a7745-cpg-mssr
> +              - renesas,r8a77470-cpg-mssr
> +              - renesas,r8a7790-cpg-mssr
> +              - renesas,r8a7791-cpg-mssr
> +              - renesas,r8a7793-cpg-mssr
> +              - renesas,r8a7794-cpg-mssr
> +
> +    then:
> +      properties:
> +        clock:
> +          minItems: 2
> +        clock-names:
> +          minItems: 2
> +          items:
> +            - const: extal
> +            - const: usb_extal
> +
> +  - if:
> +      properties:
> +        compatible:
> +          items:
> +            enum:
> +              - renesas,r8a774a1-cpg-mssr
> +              - renesas,r8a774b1-cpg-mssr
> +              - renesas,r8a7795-cpg-mssr
> +              - renesas,r8a7796-cpg-mssr
> +              - renesas,r8a77961-cpg-mssr
> +              - renesas,r8a77965-cpg-mssr
> +              - renesas,r8a77970-cpg-mssr
> +              - renesas,r8a77980-cpg-mssr
> +
> +    then:
> +      properties:
> +        clock:
> +          minItems: 2
> +        clock-names:
> +          minItems: 2
> +          items:
> +            - const: extal
> +            - const: extalr
> +
> +  - if:
> +      not:
> +        properties:
> +          compatible:
> +            items:
> +              enum:
> +                - renesas,r7s9210-cpg-mssr
> +    then:
> +      required:
> +        - '#reset-cells'

It may make sense to split this binding up into multiple bindings so
that we don't have deeply nested if/else/then.

> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - '#clock-cells'
> +  - '#power-domain-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    // CPG device node:
> +
> +    cpg: clock-controller@e6150000 {
> +            compatible = "renesas,r8a7795-cpg-mssr";
> +            reg = <0xe6150000 0x1000>;
> +            clocks = <&extal_clk>, <&extalr_clk>;
> +            clock-names = "extal", "extalr";
> +            #clock-cells = <2>;
> +            #power-domain-cells = <0>;
> +            #reset-cells = <1>;
> +    };
> +
> +  - |
> +    // CPG/MSSR Clock Domain member device node:
> +    #include <dt-bindings/clock/r8a7795-cpg-mssr.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    scif2: serial@e6e88000 {
> +            compatible = "renesas,scif-r8a7795", "renesas,rcar-gen3-scif",
> +                         "renesas,scif";
> +            reg = <0xe6e88000 64>;
> +            interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;
> +            clocks = <&cpg CPG_MOD 310>, <&cpg CPG_CORE R8A7795_CLK_S3D1>,
> +                     <&scif_clk>;
> +            clock-names = "fck";
> +            dmas = <&dmac1 0x13>, <&dmac1 0x12>, <&dmac2 0x13>, <&dmac2 0x12>;
> +            dma-names = "tx", "rx", "tx", "rx";
> +            power-domains = <&cpg>;
> +            resets = <&cpg 310>;
> +    };

I'm not sure we need this in the example.