Re: [PATCH v2 2/4] dt-bindings: mfd: syscon: Drop unneeded case for syscon + simple-mfd

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Removing the `minItems: 3` constraint introduces a schema validation loophole, allowing device trees to use exactly `compatible = "syscon", "simple-mfd";` without a vendor-specific compatible string.
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commit 882002de06044bfb3632f58a13384021911573e1
Author: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

dt-bindings: mfd: syscon: Drop unneeded case for syscon + simple-mfd

This commit removes the conditional block enforcing the number of compatible
items for devices combining "syscon" and "simple-mfd". The intention was to
remove a permissive list that the author believed was unused because
specific bindings handle their own schemas.

> diff --git a/Documentation/devicetree/bindings/mfd/syscon-common.yaml b/Documentation/devicetree/bindings/mfd/syscon-common.yaml
> index 315357da146ea..b3462e876622f 100644
> --- a/Documentation/devicetree/bindings/mfd/syscon-common.yaml
> +++ b/Documentation/devicetree/bindings/mfd/syscon-common.yaml
> @@ -46,17 +46,6 @@ required:
>    - reg
>  
>  allOf:
> -  - if:
> -      properties:
> -        compatible:
> -          contains:
> -            const: simple-mfd
> -    then:
> -      properties:
> -        compatible:
> -          minItems: 3
> -          maxItems: 5

[Severity: Medium]
Does removing this conditional block reintroduce a schema validation loophole?

By removing the minItems requirement for simple-mfd, the compatible array
length constraint falls back to the base minimum of 2 defined earlier in the
file. Since syscon-common.yaml uses additionalProperties: true, device tree
nodes using exactly "syscon", "simple-mfd" without a vendor-specific
compatible string might now silently pass validation.

Are there still undocumented device tree nodes in the kernel
(such as arch/arm/boot/dts/nxp/imx/imx51-ts4800.dts) using exactly this
2-item compatible string that will now bypass validation instead of being
properly flagged as errors?

> -
>    - if:
>        properties:
>          compatible:

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Sashiko AI review · https://sashiko.dev/#/patchset/20260608-n-dt-bindings-simple-bus-syscon-v2-0-0203e6c249dc@oss.qualcomm.com?part=2