Re: [PATCH 3/7] dt-bindings: spi: dw-apb-ssi: Convert bindings to json-schema

[Rob Herring <robh@kernel.org>]

On Thu, Mar 12, 2020 at 07:31:25PM +0800, Wan Ahmad Zainie wrote:
> Convert the Synopsis DesignWare dw-apb-ssi binding to DT schema format
> using json-schema.
> 
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
> ---
>  .../bindings/spi/snps,dw-apb-ssi.txt          |  41 -------
>  .../bindings/spi/snps,dw-apb-ssi.yaml         | 102 ++++++++++++++++++
>  2 files changed, 102 insertions(+), 41 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
>  create mode 100644 Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
> 
> diff --git a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> deleted file mode 100644
> index 3ed08ee9feba..000000000000
> --- a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> +++ /dev/null
> @@ -1,41 +0,0 @@
> -Synopsys DesignWare AMBA 2.0 Synchronous Serial Interface.
> -
> -Required properties:
> -- compatible : "snps,dw-apb-ssi" or "mscc,<soc>-spi", where soc is "ocelot" or
> -  "jaguar2", or "amazon,alpine-dw-apb-ssi"
> -- reg : The register base for the controller. For "mscc,<soc>-spi", a second
> -  register set is required (named ICPU_CFG:SPI_MST)
> -- interrupts : One interrupt, used by the controller.
> -- #address-cells : <1>, as required by generic SPI binding.
> -- #size-cells : <0>, also as required by generic SPI binding.
> -- clocks : phandles for the clocks, see the description of clock-names below.
> -   The phandle for the "ssi_clk" is required. The phandle for the "pclk" clock
> -   is optional. If a single clock is specified but no clock-name, it is the
> -   "ssi_clk" clock. If both clocks are listed, the "ssi_clk" must be first.
> -
> -Optional properties:
> -- clock-names : Contains the names of the clocks:
> -    "ssi_clk", for the core clock used to generate the external SPI clock.
> -    "pclk", the interface clock, required for register access. If a clock domain
> -     used to enable this clock then it should be named "pclk_clkdomain".
> -- cs-gpios : Specifies the gpio pins to be used for chipselects.
> -- num-cs : The number of chipselects. If omitted, this will default to 4.
> -- reg-io-width : The I/O register width (in bytes) implemented by this
> -  device.  Supported values are 2 or 4 (the default).
> -
> -Child nodes as per the generic SPI binding.
> -
> -Example:
> -
> -	spi@fff00000 {
> -		compatible = "snps,dw-apb-ssi";
> -		reg = <0xfff00000 0x1000>;
> -		interrupts = <0 154 4>;
> -		#address-cells = <1>;
> -		#size-cells = <0>;
> -		clocks = <&spi_m_clk>;
> -		num-cs = <2>;
> -		cs-gpios = <&gpio0 13 0>,
> -			   <&gpio0 14 0>;
> -	};
> -
> diff --git a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
> new file mode 100644
> index 000000000000..57a789f5d9f3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
> @@ -0,0 +1,102 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/spi/snps,dw-apb-ssi.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Synopsys DesignWare AMBA 2.0 Synchronous Serial Interface
> +
> +maintainers:
> +  - Mark Brown <broonie@kernel.org>

Should be owner for this h/w, not who takes patches.

> +
> +allOf:
> +  - $ref: spi-controller.yaml#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - mscc,ocelot-spi
> +              - mscc,jaguar2-spi
> +      - items:
> +          - const: amazon,alpine-dw-apb-ssi
> +      - items:
> +          - const: snps,dw-apb-ssi

This can all be a single 'enum'. You only need 'oneOf' if there are a 
different number of compatible entries.

> +
> +  reg:
> +    minItems: 1
> +    maxItems: 2
> +    oneOf:
> +      - items:
> +          - description: The register base for the controller.
> +      - items:
> +          - description: The register base for the controller.
> +          - description: For "mscc,<soc>-spi", a second register set is
> +                         required (named ICPU_CFG:SPI_MST)

No need for the oneOf. The 2nd case is a superset of the 1st.

> +
> +  interrupts:
> +    maxItems: 1
> +    description: One interrupt, used by the controller.

Can drop description. Not specific to this h/w.

> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0

Drop these 2. Covered by spi-controller.yaml.

> +
> +  clocks:
> +    minItems: 1
> +    maxItems: 2
> +    description: |
> +      phandles for the clocks, see the description of clock-names below.
> +      The phandle for the "ssi_clk" is required. The phandle for the "pclk"
> +      clock is optional. If a single clock is specified but no clock-name,
> +      it is the "ssi_clk" clock. If both clocks are listed, the "ssi_clk"
> +      must be first.

Rework like:

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

> +
> +  clock-names:
> +    items:
> +      - const: ssi_clk
> +      - const: pclk
> +    description: |
> +      Contains the names of the clocks.
> +      "ssi_clk", for the core clock used to generate the external SPI clock.
> +      "pclk", the interface clock, required for register access.

No need to repeat what's in clocks.

> +      If a clock domain used to enable this clock then it should be
> +      named "pclk_clkdomain".

Should be a constraint:

enum: [pclk, pclk_clkdomain]

But really, it probably should be dropped. I don't understand what the 
sentence is supposed to mean.

> +
> +  cs-gpios:
> +    description: Specifies the gpio pins to be used for chipselects.

Can drop, covered by spi-controller.yaml.

> +
> +  num-cs:
> +    default: 4
> +    description: The number of chipselects. If omitted, this will default to 4.

Constraints?

> +
> +  reg-io-width:
> +    default: 4
> +    description: |
> +      The I/O register width (in bytes) implemented by this device.
> +      Supported values are 2 or 4 (the default).

2 or 4?, sounds like constraints.

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - '#address-cells'
> +  - '#size-cells'
> +  - clocks
> +
> +examples:
> +  - |
> +    spi@fff00000 {
> +          compatible = "snps,dw-apb-ssi";
> +          reg = <0xfff00000 0x1000>;
> +          interrupts = <0 154 4>;
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +          clocks = <&spi_m_clk>;
> +          num-cs = <2>;
> +          cs-gpios = <&gpio0 13 0>,
> +                     <&gpio0 14 0>;
> +    };
> -- 
> 2.17.1
>