Re: [PATCH v2 09/15] dt-bindings: iio: adc: adi,ad4134: Document SPI connection mode

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] dt-bindings: invalid DTS syntax in spi-rx-bus-width const constraints
- [Medium] dt-bindings: schema allows bypassing daisy-chained-devices requirement
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commit 879c8beee9c21345a2925282a985c10001e710eb
Author: Marcelo Schmitt <marcelo.schmitt@analog.com>

dt-bindings: iio: adc: adi,ad4134: Document SPI connection mode

Document how AD4134 chips are connected to the host SPI controller
according to different wiring configurations.

> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml
> index ea6d7e0264190..012e09decf7af 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml
[ ... ]
> +  - oneOf:
> +      - required: [adi,spi-mode, '#daisy-chained-devices']
> +        properties:
> +          adi,spi-mode:
> +            const: one-channel-chain
> +          spi-rx-bus-width:
> +            const: <1>

[Severity: Medium]
Will this assignment of <1> to const cause a type mismatch during schema
validation?

Since the YAML parser evaluates <1> as a literal string instead of an integer
array, it appears that when a device tree specifies a mode like
adi,spi-mode = "one-channel-chain" and provides a valid integer for
spi-rx-bus-width = <1>, it will unconditionally fail validation.

> +      - required: [adi,spi-mode, '#daisy-chained-devices']
> +        properties:
> +          adi,spi-mode:
> +            const: two-channel-chain
> +          spi-rx-bus-width:
> +            const: <1>, <1>

[Severity: Medium]
Does this string literal assignment also trigger a type mismatch when validating
a two-channel-chain configuration?

> +      - properties:
> +          '#daisy-chained-devices': false

[Severity: Medium]
Can the fallback branch in this oneOf block inadvertently bypass the required
constraints?

If a device tree completely omits the #daisy-chained-devices property, this
catch-all branch seems to trivially evaluate to true, because property
constraints in JSON Schema only evaluate if the property is actually present.

If the branch evaluates to true, the outer oneOf block succeeds. This appears
to circumvent the mandatory #daisy-chained-devices requirement, allowing
incomplete configurations to pass validation when adi,spi-mode is set to one
of the chain modes.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1789494473.git.marcelo.schmitt@analog.com?part=9