Re: [PATCH v4 1/2] dt-bindings: rtc: Add property for Raspberry Pi 5 RTC

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] dt-bindings: minimum and maximum constraints are ignored due to array isolation
--

commit ff7cdbdeb8fcd609ef36f409f92bd2d94dc107d7
Author: Sander Speetjens <sander.speetjens@gmail.com>

dt-bindings: rtc: Add property for Raspberry Pi 5 RTC

The Raspberry Pi 5 has a built-in RTC that can be battery-backed
via the VBAT pin. Expose the trickle-voltage-millivolt DT property so the
driver can program the correct charge voltage for board specific
configurations with the attached battery.

> diff --git a/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml b/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
> index 983ea80eaec97..9349fc8908a50 100644
> --- a/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
> +++ b/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
> @@ -133,6 +133,13 @@ properties:
>      required:
>        - compatible
>  
> +  trickle-voltage-millivolt:
> +    allOf:
> +      - $ref: /schemas/rtc/rtc.yaml#/properties/trickle-voltage-millivolt
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +      - minimum: 1300
> +        maximum: 5000

[Severity: Low]
Are the minimum and maximum constraints ignored here due to being placed in a
separate dictionary under allOf?

In dt-schema, properties using scalar types like uint32 are parsed as arrays.
The JSON Schema minimum and maximum keywords only apply to numeric instances,
so when applied to an array, they are silently ignored. The dt-schema
preprocessor fixes this by pushing constraints into the items schema, but only
if they reside in the exact same dictionary as the reference to
/schemas/types.yaml#/definitions/uint32.

Because minimum and maximum are placed in a separate dictionary within the
allOf list, the preprocessor misses them, leaving them ineffective. Out-of-bounds
trickle-voltage-millivolt values could silently pass dt_binding_check validation.

> +
>  required:
>    - compatible
>    - mboxes

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260923131323.1099979-1-sander.speetjens@gmail.com?part=1