Re: [PATCH 1/2] dt-bindings: thermal: amlogic: describe bus clock for t7-thermal

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] dt-bindings: thermal: amlogic: ABI breakage by prepending new bus clock
--

commit 9cad8324bf204ceb98e53aadbfac54a0b8d04da6
Author: Ronald Claveau <linux-kernel-dev@aliel.fr>

dt-bindings: thermal: amlogic: describe bus clock for t7-thermal

This commit updates the amlogic thermal device tree binding to support a
secondary "bus" clock required by the t7-thermal sensor. It adds the
"clock-names" property to distinguish between the "bus" and "core" clocks
and requires both for the t7-thermal compatible.

> diff --git a/Documentation/devicetree/bindings/thermal/amlogic,thermal.yaml b/Documentation/devicetree/bindings/thermal/amlogic,thermal.yaml
> index 8cfa44dcda58c..e72cb39ac635d 100644
> --- a/Documentation/devicetree/bindings/thermal/amlogic,thermal.yaml
> +++ b/Documentation/devicetree/bindings/thermal/amlogic,thermal.yaml
> @@ -32,7 +32,15 @@ properties:
>      maxItems: 1
>  
>    clocks:
> -    maxItems: 1
> +    minItems: 1
> +    items:
> +      - description: Bus clock, gates register access to the sensor.
> +      - description: Functional clock of the temperature sensor, shared between sensors.
> +
> +  clock-names:
> +    items:
> +      - const: bus
> +      - const: core

[Severity: Critical]
Does prepending the new "bus" clock at index 0 introduce an ABI regression?

Since older kernels use devm_clk_get(dev, NULL) to unconditionally fetch
the clock at index 0 (as seen in drivers/thermal/amlogic_thermal.c:
amlogic_thermal_probe()), updating the device tree to match this new schema
will cause those older kernels to fetch the "bus" clock instead of the
functional "core" clock.

This will leave the functional clock disabled and prevent the thermal sensor
from operating. While a later patch in this series updates the driver to use
devm_clk_bulk_get_all(), the device tree schema remains broken for older
kernels.

Would it be better to append the new "bus" clock at index 1 to avoid
breaking backward and forward compatibility?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260923-fix-t7-thermal-clock-v1-0-7d4c4682f182@aliel.fr?part=1

_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic