Re: [PATCH v3 09/21] arm64: dts: apple: t8103-jxxx: Add regulators for CS42L83 power supply

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] arm64: dts: apple: duplicate node names in t8103-jxxx.dtsi merge regulators
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commit d0005942339444378649a8aca2fe8ee2e51f9a6a
Author: James Calligeros <jcalligeros99@gmail.com>

arm64: dts: apple: t8103-jxxx: Add regulators for CS42L83 power supply

This commit adds five fixed-regulator nodes to the Apple T8103 template
devicetree to serve as stand-in power supplies for the CS42L83 codec.

> diff --git a/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi b/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi
> index 686fb1dd215d2..7483fc5cbd204 100644
> --- a/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi
> +++ b/arch/arm64/boot/dts/apple/t8103-jxxx.dtsi
> @@ -38,6 +38,38 @@ memory@800000000 {
>  		device_type = "memory";
>  		reg = <0x8 0 0x2 0>; /* To be filled by loader */
>  	};
> +
> +	/*
> +	 * The CS42L83 found on all T8103 boards requires VA, VCP, VCP_FILT,
> +	 * VL, VD and VP regulators. We don't (officially) know how power
> +	 * gets to the codec, so these fixed regulators are stand-ins.
> +	 */
> +	jack_va_reg: regulator {
> +		compatible = "regulator-fixed";
> +		regulator-name = "jack-va";
> +	};
> +
> +	/* CS42L83 VCP and VCP_FILT */
> +	jack_vcp_reg: regulator {
> +		compatible = "regulator-fixed";
> +		regulator-name = "jack-vcp";
> +	};
> +
> +	jack_vl_reg: regulator {
> +		compatible = "regulator-fixed";
> +		regulator-name = "jack-vl";
> +	};
> +
> +	/* VD_FILT */
> +	jack_vd_reg: regulator {
> +		compatible = "regulator-fixed";
> +		regulator-name = "jack-vd";
> +	};
> +
> +	jack_vp_reg: regulator {
> +		compatible = "regulator-fixed";
> +		regulator-name = "jack-vp";
> +	};

[Severity: Medium]
Won't giving all five sibling nodes under / the identical node name
"regulator" cause dtc to merge them into a single /regulator node?

When a T8103 board DTS includes t8103.dtsi (which defines /) followed by
t8103-jxxx.dtsi (which re-opens /), dtc merges the two root nodes via
merge_nodes() in scripts/dtc/livetree.c:

    for_each_child_withdel(old_node, old_child) {
        if (streq(old_child->name, new_child->name)) {
            merge_nodes(old_child, new_child);
            new_child = NULL;
            break;
        }
    }

    if (new_child)
        add_child(old_node, new_child);

The first child named "regulator" (jack_va_reg) is added to /, and the
remaining four sibling nodes named "regulator" (jack_vcp_reg, jack_vl_reg,
jack_vd_reg, and jack_vp_reg) match streq(old_child->name, new_child->name)
and are merged into that single /regulator node. As a result, all five
labels resolve to the same node and each definition overwrites
regulator-name until only "jack-vp" remains.

Should each node be given a distinct name matching
Documentation/devicetree/bindings/regulator/fixed-regulator.yaml, such as
regulator-jack-va, regulator-jack-vcp, regulator-jack-vl,
regulator-jack-vd, and regulator-jack-vp?

>  };
>  
>  &serial0 {

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261018-macaudio-v3-0-abdff7741dea@gmail.com?part=9