Re: [PATCH] dts: riscv: spacemit: k3: Fix I/O power settings

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The newly added `spacemit,apbc` DT property triggers a spurious boot warning and relies on a fragile probe deferral dependency, because the target `syscon_apbc` node lacks the `"syscon"` compatible string.
--

commit 89bb8c89cecf7c32a2e825a2b8f604c5c45762bd
Author: Yixun Lan <dlan@kernel.org>

dts: riscv: spacemit: k3: Fix I/O power settings
    
SpacemiT K3 SoC support dual-voltage I/O power domain, while initially
configure to 3.3v, and need to access register from APBC space to switch
to 1.8v domain.
    
Fix the GMAC0's I/O pins 1.8v switch failure that will result a broken
ethernet driver.

> diff --git a/arch/riscv/boot/dts/spacemit/k3.dtsi b/arch/riscv/boot/dts/spacemit/k3.dtsi
> index 815debd16409b..2b0bf9cd755bd 100644
> --- a/arch/riscv/boot/dts/spacemit/k3.dtsi
> +++ b/arch/riscv/boot/dts/spacemit/k3.dtsi
> @@ -803,6 +803,7 @@ pinctrl: pinctrl@d401e000 {
>  			clocks = <&syscon_apbc CLK_APBC_AIB>,
>  				 <&syscon_apbc CLK_APBC_AIB_BUS>;
>  			clock-names = "func", "bus";
> +			spacemit,apbc = <&syscon_apbc>;

Does this newly added spacemit,apbc property trigger a spurious boot warning
and rely on a fragile probe deferral dependency?

Looking at the referenced syscon_apbc node, it lacks the "syscon" compatible
string.

This prevents syscon_node_to_regmap() from instantiating the regmap
on-the-fly, causing it to return -EPROBE_DEFER if the pinctrl driver probes
before the clock driver registers the regmap.

The pinctrl driver catches this with a blanket IS_ERR() check and prints a
now-spurious "no syscon found" warning during boot while discarding the
regmap pointer:

drivers/pinctrl/spacemit/pinctrl-k1.c:spacemit_pinctrl_probe() {
	...
	pctrl->regmap_apbc = syscon_regmap_lookup_by_phandle(np, "spacemit,apbc");
	if (IS_ERR(pctrl->regmap_apbc)) {
		dev_warn(dev, "no syscon found, disable power voltage switch functionality\n");
		pctrl->regmap_apbc = NULL;
	}
	...
}

The voltage switch functionality only ultimately succeeds because the
subsequent devm_clk_get_enabled() call against the same node also returns
-EPROBE_DEFER.

This gives the clock driver time to probe and register the regmap before the
pinctrl driver retries.

Would adding "syscon" to the syscon_apbc node's compatible string, or
explicitly handling -EPROBE_DEFER in the pinctrl driver, resolve this issue
and prevent the spurious warning?

>  		};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260518-07-dts-pinctrl-io-power-v1-1-abe19c14a726@kernel.org?part=1