From: sashiko-bot@kernel.org
To: Prabhakar <prabhakar.csengg@gmail.com>
Cc: devicetree@vger.kernel.org, linux-clk@vger.kernel.org,
robh@kernel.org, conor+dt@kernel.org,
linux-watchdog@vger.kernel.org, wsa+renesas@sang-engineering.com
Subject: Re: [PATCH v8 6/7] arm64: dts: renesas: r9a09g077: Use CPG/MSSR syscon for WDTDCR access
Date: Thu, 01 Oct 2026 17:03:08 +0000 [thread overview]
Message-ID: <20261001170308.B5A0C1F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20261001165201.763882-7-prabhakar.mahadev-lad.rj@bp.renesas.com>
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] dt-bindings: ABI breakage in r9a09g077 wdt nodes due to removed reg
--
commit 73d1717297166d802fe57978f0ccd518dcd4b8df
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
arm64: dts: renesas: r9a09g077: Use CPG/MSSR syscon for WDTDCR access
This commit replaces the direct mapping of WDTDCR registers with a syscon
regmap interface. The individual watchdog nodes now use the renesas,sysc
property instead of multiple reg entries.
> diff --git a/arch/arm64/boot/dts/renesas/r9a09g077.dtsi b/arch/arm64/boot/dts/renesas/r9a09g077.dtsi
> index 674e35e4f2425..18d748661a609 100644
> --- a/arch/arm64/boot/dts/renesas/r9a09g077.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r9a09g077.dtsi
> @@ -327,61 +327,61 @@ channel1 {
>
> wdt0: watchdog@80082000 {
> compatible = "renesas,r9a09g077-wdt";
> - reg = <0 0x80082000 0 0x400>,
> - <0 0x81295100 0 0x04>;
> + reg = <0 0x80082000 0 0x400>;
[Severity: Critical]
Does removing this second reg entry break forward compatibility for older
kernels?
Older kernels that unconditionally expect to map index 1 for the
renesas,r9a09g077-wdt binding during probe will fail to initialize the
watchdog device when booted with this updated device tree. Calling
devm_platform_ioremap_resource(pdev, 1) will return -EINVAL and abort
the probe.
Since device tree files are treated as firmware ABIs, removing the reg entry
without providing a fallback or changing the compatible string constitutes an
ABI breakage. Could the second reg entry be retained alongside the new
renesas,sysc property to preserve compatibility?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261001165201.763882-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=6
next prev parent reply other threads:[~2026-10-01 17:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 16:51 [PATCH v8 0/7] Add syscon support for Renesas WDT driver Prabhakar
2026-10-01 16:51 ` [PATCH v8 1/7] clk: renesas: r9a09g077: Add helper to start WDTDCR counter Prabhakar
2026-10-01 16:51 ` [PATCH v8 2/7] watchdog: rzv2h: Use pm_runtime_put_sync() Prabhakar
2026-10-01 16:51 ` [PATCH v8 3/7] watchdog: rzv2h: Drop WDTRCR_RSTIRQS define Prabhakar
2026-10-01 16:51 ` [PATCH v8 4/7] watchdog: rzv2h: Drop runtime PM handling from WDTDCR init Prabhakar
2026-10-01 16:51 ` [PATCH v8 5/7] watchdog: rzv2h_wdt: Add syscon based WDTDCR access Prabhakar
2026-10-01 16:52 ` [PATCH v8 6/7] arm64: dts: renesas: r9a09g077: Use CPG/MSSR syscon for " Prabhakar
2026-10-01 17:03 ` sashiko-bot [this message]
2026-10-01 16:52 ` [PATCH v8 7/7] arm64: dts: renesas: r9a09g087: " Prabhakar
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