Re: [PATCH 4/5] arm64: dts: freescale: Add LVDS overlays for TQMa8Xx

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Am Dienstag, 13. Oktober 2026, 13:28:27 Mitteleuropäische Sommerzeit schrieb sashiko-bot@kernel.org:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] dts: unit address mismatch in dc0_pc channel@1 breaks LVDS1 hardware mapping
> --
> 
> commit 9e71d1e0ae4bcdbdae19947de71699d2eb47af70
> Author: Alexander Stein <alexander.stein@ew.tq-group.com>
> 
> arm64: dts: freescale: Add LVDS overlays for TQMa8Xx
> 
> Add overlays for the supported LVDS display tianma tm070jvhg33 on both
> LVDS0 and LVDS1 channels on connector X14 (+ control on X22).
> The corresponding display controller PLL is configured with 10x the
> pixelclock.
> 
> > diff --git a/arch/arm64/boot/dts/freescale/mba8xx-lvds1-tm070jvhg33.dtso b/arch/arm64/boot/dts/freescale/mba8xx-lvds1-tm070jvhg33.dtso
> > new file mode 100644
> > index 0000000000000..4a8ba61962725
> > --- /dev/null
> > +++ b/arch/arm64/boot/dts/freescale/mba8xx-lvds1-tm070jvhg33.dtso
> 
> [ ... ]
> 
> > +&dc0_pc {
> > +	#address-cells = <1>;
> > +	#size-cells = <0>;
> > +	status = "okay";
> > +
> > +	channel@1 {
> > +		reg = <0>;
> 
> [Severity: High]
> Does this reg value incorrectly map channel@1 to hardware index 0 instead of 1?
> 
> It appears this overrides the channel@1 child node of &dc0_pc but explicitly
> sets reg = <0>. This will incorrectly update hardware channel 0, overriding the
> base device tree which expects channel 1, and will also trigger a DTC unit
> address mismatch warning.
> 
> This can cause the LVDS1 display output to not function correctly because its
> pixel combiner channel configuration is applied to channel 0 instead of
> channel 1.

Ah, that's true. Will fix in v2.
Actually I would like to skip those "overwrites" as the value are already set
in base .dtsi. But then dtbs_check complains like this:
> /fragment@3/__overlay__/channel@1: node has a unit name, but no reg or ranges property

Best regards,
Alexander

> > +		status = "okay";
> > +	};
> > +};
> 
> 


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