Re: [PATCH v2 03/11] ARM: dts: imx6ul: Add Variscite SoM and DART base files

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Missing voltage constraints on touch_3v3_regulator break ADC scale
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commit 1c2bc49be02f8a5da660fe024ca1908ba6a36cd7
Author: Stefano Radaelli <stefano.r@variscite.com>
ARM: dts: imx6ul: Add Variscite SoM and DART base files

Add shared DTSI files for the VAR-SOM-6UL and DART-6UL modules and
SoC-specific wrappers for i.MX6UL, i.MX6ULL and i.MX6ULZ.

Keep storage, audio and carrier options in separate DTSI files so
board variants can include the hardware assembled on each board.

> diff --git a/arch/arm/boot/dts/nxp/imx/imx6ul-imx6ull-var-dart.dtsi b/arch/arm/boot/dts/nxp/imx/imx6ul-imx6ull-var-dart.dtsi
> new file mode 100644
> index 0000000000000..3cbfea6e2b24c
> --- /dev/null
> +++ b/arch/arm/boot/dts/nxp/imx/imx6ul-imx6ull-var-dart.dtsi
> @@ -0,0 +1,205 @@
[ ... ]
> +	touch_3v3_regulator: regulator-touch-3v3 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "touch_3v3_supply";
> +		regulator-always-on;
> +	};

[Severity: Medium]
Does the missing voltage constraints here break the ADC scale?

Without regulator-min-microvolt and regulator-max-microvolt constraints,
the voltage is unknown and regulator_get_voltage() returns -EINVAL.

The vf610-adc driver stores this error code in an unsigned integer variable
(u32 vref_uv), causing an underflow to ~4.29 billion.

This garbage value is then exposed to userspace as the channel's scale when
reading in_voltageX_scale sysfs attributes, breaking functional ADC
measurements.

> diff --git a/arch/arm/boot/dts/nxp/imx/imx6ul-imx6ull-var-som.dtsi b/arch/arm/boot/dts/nxp/imx/imx6ul-imx6ull-var-som.dtsi
> new file mode 100644
> index 0000000000000..7c778adfeb13e
> --- /dev/null
> +++ b/arch/arm/boot/dts/nxp/imx/imx6ul-imx6ull-var-som.dtsi
> @@ -0,0 +1,201 @@
[ ... ]
> +	touch_3v3_regulator: regulator-touch-3v3 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "touch_3v3_supply";
> +		regulator-always-on;
> +	};

[Severity: Medium]
Does this duplicated definition also miss the voltage constraints and break
the ADC scale in the same way?

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Sashiko AI review · https://sashiko.dev/#/patchset/cover.1790413032.git.stefano.r@variscite.com?part=3