Re: [PATCH 1/3] dt-bindings: iio: adc: Add syscon property for multi-SCU SoCs

[Krzysztof Kozlowski <krzk@kernel.org>]

On Thu, Oct 01, 2026 at 11:28:44AM +0800, Billy Tsai wrote:
> The ADC's reference-voltage trimming data lives in a System Control
> Unit (SCU) register. SoCs with a single SCU instance let the driver
> locate it without any additional information, but SoCs such as AST2700
> that expose more than one SCU node need an explicit phandle to
> disambiguate which one holds the trimming data.
> 
> Add an optional "syscon" phandle property, and require it for the
> AST2700 compatibles since they are the first multi-SCU SoCs supported
> by this driver.
> 
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> Assisted-by: Claude:claude-sonnet-5
> ---
>  .../bindings/iio/adc/aspeed,ast2600-adc.yaml       | 28 ++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/aspeed,ast2600-adc.yaml b/Documentation/devicetree/bindings/iio/adc/aspeed,ast2600-adc.yaml
> index 249101b55cf4e..0d6b10450cfa8 100644
> --- a/Documentation/devicetree/bindings/iio/adc/aspeed,ast2600-adc.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/aspeed,ast2600-adc.yaml
> @@ -67,6 +67,11 @@ properties:
>      description:
>        Inform the driver that last channel will be used to sensor battery.
>  
> +  syscon:

Missing vendor and descriptive name. Please read writing bindings.

> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      Required on SoCs with more than one SCU instance (e.g. AST2700).

Describe the purpose, not open code schema.

> +
>  required:
>    - compatible
>    - reg
> @@ -74,6 +79,18 @@ required:
>    - resets
>    - "#io-channel-cells"
>  
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - aspeed,ast2700-adc0
> +              - aspeed,ast2700-adc1
> +    then:
> +      required:
> +        - syscon
> +
>  additionalProperties: false
>  
>  examples:
> @@ -95,4 +112,15 @@ examples:
>          #io-channel-cells = <1>;
>          aspeed,int-vref-microvolt = <2500000>;
>      };
> +  - |
> +    #include <dt-bindings/clock/aspeed,ast2700-scu.h>
> +    #include <dt-bindings/reset/aspeed,ast2700-scu.h>

No need for a new exmaple for one new property.

Best regards,
Krzysztof