[PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock

Stephen Boyd sboyd at kernel.org
Thu Aug 5 17:30:19 PDT 2021


> diff --git a/Documentation/devicetree/bindings/clock/armada3700-uart-clock.yaml b/Documentation/devicetree/bindings/clock/armada3700-uart-clock.yaml
> new file mode 100644
> index 000000000000..5ef04f3affda
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/armada3700-uart-clock.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/marvell,armada-3700-uart-clock#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +title: Marvell Armada 3720 UART clocks

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> +properties:
> +  compatible:
> +    const: marvell,armada-3700-uart-clock

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> +  reg:
> +    items:
> +      - description: UART Clock Control Register
> +      - description: UART 2 Baud Rate Divisor Register

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> +  clocks:
> +    description: |
> +      List of parent clocks suitable for UART from following set:
> +        "TBG-A-P", "TBG-B-P", "TBG-A-S", "TBG-B-S", "xtal"
> +      UART clock can use one from this set and when more are provided
> +      then kernel would choose and configure the most suitable one.
> +      It is suggest to specify at least one TBG clock to achieve
> +      baudrates above 230400 and also to specify clock which bootloader
> +      used for UART (most probably xtal) for smooth boot log on UART.

Please use items and const like clock-names for the clocks property. The
description makes me feel like the DT is configuring the choices
available. Ideally, the clocks and clock-names properties are fixed in
length and never change unless the compatible changes.

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> +  clock-names:
> +    items:
> +      - const: TBG-A-P
> +      - const: TBG-B-P
> +      - const: TBG-A-S
> +      - const: TBG-B-S
> +      - const: xtal
> +    minItems: 1
> +    maxItems: 5

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> +  '#clock-cells':
> +    const: 1

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> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - '#clock-cells'

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> +additionalProperties: false

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> +examples:
> +  - |
> +    uartclk: uartclk at 12000 {
> +      compatible = "marvell,armada-3700-uart-clock";
> +      reg = <0x12010 0x4>, <0x12210 0x4>;
> +      clocks = <&tbg 0>, <&tbg 1>, <&tbg 2>, <&tbg 3>, <&xtalclk>;
> +      clock-names = "TBG-A-P", "TBG-B-P", "TBG-A-S", "TBG-B-S", "xtal";
> +      #clock-cells = <1>;
> +    };



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