Re: [PATCH 1/2] dt-bindings: iio: adc: add ad7944 ADCs

[David Lechner]

On Tue, Feb 6, 2024 at 11:26 AM David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>
> This adds a new binding for the Analog Devices, Inc. AD7944, AD7985, and
> AD7986 ADCs.
>
> Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
> ---
>  .../devicetree/bindings/iio/adc/adi,ad7944.yaml    | 231 +++++++++++++++++++++
>  MAINTAINERS                                        |   8 +
>  2 files changed, 239 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
> new file mode 100644
> index 000000000000..a023adbeba42
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml

..


+  adi,reference:
+    $ref: /schemas/types.yaml#/definitions/string
+    enum: [ internal, internal-buffer, external ]
+    default: internal

..

> +allOf:
> +  # ref-supply is only used for external reference voltage
> +  - if:
> +      not:
> +        required:
> +          - adi,reference
> +    then:
> +      properties:
> +        ref-supply: false
> +    else:
> +      if:
> +        properties:
> +          adi,reference:
> +            const: external
> +      then:
> +        required:
> +          - ref-supply
> +      else:
> +        properties:
> +          ref-supply: false

This seems like something that could potentially be improved in the
dtschema tooling. Since adi,reference has a default of "internal", I
would expect:

     if:
       properties:
         adi,reference:
           const: external
     then:
       required:
         - ref-supply
     else:
       properties:
         ref-supply: false

to be sufficient here. However, currently, if the adi,reference
property is omitted from the dts/dtb, the condition here evaluates to
true and unexpectedly (incorrectly?) the validator requires the
ref-supply property.