Re: [PATCH v2 1/6] dt-bindings: power: qcom-rpmpd: Remove unused MSM8953 indices

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] dt-bindings: ABI breakage by removing MSM8953_VDDMD index
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commit e44d0dc9a145a838a007b1d8e81abb98d56a4d20
Author: Barnabás Czémán <barnabas.czeman@mainlining.org>

dt-bindings: power: qcom-rpmpd: Remove unused MSM8953 indices

This commit removes MSM8953_VDDMD and MSM8953_VDDMD_AO from the MSM8953 power
domain bindings, as the hardware now uses mss-supply as a regulator. It also
defines RPMPD_VDDMD for the SDM632 MSS.

> diff --git a/include/dt-bindings/power/qcom-rpmpd.h b/include/dt-bindings/power/qcom-rpmpd.h
> index 4371ac941f29d..120f8855b4275 100644
> --- a/include/dt-bindings/power/qcom-rpmpd.h
> +++ b/include/dt-bindings/power/qcom-rpmpd.h

[ ... ]

> @@ -84,8 +85,6 @@
>  #define QM215_VDDMX_AO		MSM8917_VDDMX_AO
>  
>  /* MSM8953 Power Domain Indexes */
> -#define MSM8953_VDDMD		0
> -#define MSM8953_VDDMD_AO	1

[Severity: Critical]
Does removing these identifiers explicitly break the established DT ABI?

Older compiled device trees (DTBs) for the MSM8953 platform encode the power
domain index 0 for MSM8953_VDDMD in the mss (modem) node's power-domains
property. Removing this index from the dt-bindings header and driver removes
support for these existing DTBs, causing a backward compatibility regression.

When booting a new kernel with an older DTB that uses MSM8953_VDDMD, the new
qcom_q6v5_mss driver expects an mss-supply regulator. With the old DTB, the
new kernel will fail to find mss-supply, rendering the modem subsystem
non-functional during system boot.

Is there a fallback mechanism planned to ensure older device trees still probe
successfully?

>  #define MSM8953_VDDCX		2
>  #define MSM8953_VDDCX_AO	3
>  #define MSM8953_VDDCX_VFL	4

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Sashiko AI review · https://sashiko.dev/#/patchset/20260929-sdm632-rpmpd-v2-0-97ef8858161b@mainlining.org?part=1