Re: [PATCH 1/2] dt-bindings: clock: Add reg-clock-controller

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 14/04/2023 20:12, David Yang wrote:
> Add DT bindings documentation for reg-clock-controller, collection of
> basic clocks common to many platforms.
> 
> Signed-off-by: David Yang <mmyangfl@gmail.com>
> ---
>  .../bindings/clock/reg-clock-controller.yaml  | 245 ++++++++++++++++++
>  1 file changed, 245 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/reg-clock-controller.yaml
> 
> diff --git a/Documentation/devicetree/bindings/clock/reg-clock-controller.yaml b/Documentation/devicetree/bindings/clock/reg-clock-controller.yaml
> new file mode 100644
> index 000000000000..a6a7e0b05821
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/reg-clock-controller.yaml
> @@ -0,0 +1,245 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/reg-clock-controller.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Simple straight-forward register-based clocks
> +
> +maintainers:
> +  - David Yang <mmyangfl@gmail.com>
> +
> +description: |
> +  Basic clocks common to many platforms.
> +
> +  If your clocks don't fit into these catagories, simply create your clock

typo: categories

> +  controller. This driver normally work well with other controllers as long as
> +  they operate on different registers.
> +
> +  See linux/clk-provider.h for details about properties for each type of clock.

Describe here what is this device, what such simple clock controller
represents.

> +
> +properties:
> +  compatible:
> +    enum:
> +      - reg-clock-controller
> +
> +  ranges: true
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 1
> +
> +required:
> +  - compatible
> +  - ranges
> +  - '#address-cells'
> +  - '#size-cells'

required goes after patternProperties.

> +
> +patternProperties:
> +  ".*gate-clock@.*":

"gate-clock@" should be equivalent. However this should be just "clock".

> +    type: object
> +
> +    description: |

Do not need '|' unless you need to preserve formatting.

> +      Clock which can gate its output.
> +
> +    properties:
> +      compatible:
> +        const: gate-clock
> +
> +      reg:
> +        maxItems: 1
> +
> +      '#clock-cells':
> +        const: 0
> +
> +      clocks:
> +        maxItems: 1
> +        description:
> +          Parent clock.
> +
> +      clock-output-name:

names

Don't create your own properties.

> +        maxItems: 1
> +
> +      bit-index:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Bit index which controls the output.

I suggest to use same property as nvme, so bits.

> +
> +    required:
> +      - compatible
> +      - reg
> +      - '#clock-cells'
> +      - bit-index
> +
> +    additionalProperties: false
> +
> +  ".*divider-clock@.*":
> +    type: object
> +
> +    description: |
> +      Clock with an adjustable divider affecting its output frequency.
> +
> +    properties:
> +      compatible:
> +        const: divider-clock
> +
> +      reg:
> +        maxItems: 1
> +
> +      '#clock-cells':
> +        const: 0
> +
> +      clocks:
> +        description:
> +          Parent clocks.
> +
> +      clock-output-name:
> +        maxItems: 1
> +
> +      shift:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Shift to the divider bit field.
> +
> +      width:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Width of the divider bit field.
> +
> +      dividers:
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +        description:
> +          Array of value/divider pairs.

Then it looks like matrix.

> +
> +    required:
> +      - compatible
> +      - reg
> +      - '#clock-cells'
> +      - shift
> +      - width
> +
> +    additionalProperties: false
> +
> +  ".*mux-clock@.*":
> +    type: object
> +
> +    description: |
> +      Clock with multiple selectable parents.
> +
> +    properties:
> +      compatible:
> +        const: mux-clock
> +
> +      reg:
> +        maxItems: 1
> +
> +      '#clock-cells':
> +        const: 0
> +
> +      clocks:
> +        minItems: 1
> +        description:
> +          Parent clock.
> +
> +      clock-output-name:
> +        maxItems: 1
> +
> +      shift:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Shift to multiplexer bit field.
> +
> +      mask:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Mask of mutliplexer bit field.
> +
> +      table:
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +        description:
> +          Array of register values corresponding to the parent index.
> +
> +    required:
> +      - compatible
> +      - reg
> +      - '#clock-cells'
> +      - shift
> +      - mask
> +
> +    additionalProperties: false
> +
> +  ".*fractional-divider-clock@.*":
> +    type: object
> +
> +    description: |
> +      Clock with adjustable fractional divider affecting its output frequency.
> +
> +    properties:
> +      compatible:
> +        const: fractional_divider-clock
> +
> +      reg:
> +        maxItems: 1
> +
> +      '#clock-cells':
> +        const: 0
> +
> +      clocks:
> +        maxItems: 1
> +        description:
> +          Parent clock.
> +
> +      clock-output-name:
> +        maxItems: 1
> +
> +      numerator-shift:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Shift to the numerator bit field.
> +
> +      numerator-width:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Width of the numerator bit field.
> +
> +      denominator-shift:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Shift to the denominator bit field.
> +
> +      denominator-width:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description:
> +          Width of the denominator bit field.
> +
> +    required:
> +      - compatible
> +      - reg
> +      - '#clock-cells'
> +      - numerator-shift
> +      - numerator-width
> +      - denominator-shift
> +      - denominator-width
> +
> +    additionalProperties: false
> +
> +additionalProperties: true

No, come on. This must be false.

> +
> +examples:
> +  - |
> +    clks: reg-clk-ctrl@ffff0000 {

Names should be generic, so clock-controller

Drop the label.

> +      compatible = "reg-clock-controller";
> +      #address-cells = <1>;
> +      #size-cells = <1>;
> +      ranges = <0 0xffff0000 0x1000>;
> +
> +      my_clk: gate-clock@cc-3 {

Drop label.

That's a new unit address to me. Did I miss a change in DT spec?

> +        compatible = "gate-clock";
> +        #clock-cells = <0>;
> +        reg = <0xcc 4>;

reg is after compatible.

> +        bit-index = <3>;
> +        clock-output-name = "my-clk";

Plus, test your patches. This fails testing...

> +      };
> +    };

Best regards,
Krzysztof