Re: [PATCH v2 3/3] arm64: dts: qcom: Fix pm4125 vbus regulator compatible and constraints

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The `PM4125_VBOOST_CFG` macro is defined twice in the driver with different values, causing the voltage selector address to be shadowed by the OTG configuration address. This leads to register corruption when applying the new device tree constraints.
--

commit ee5aeefd579f49a0fd9de6178216fb53f958a898
Author: Rakesh Kota <rakesh.kota@oss.qualcomm.com>

arm64: dts: qcom: Fix pm4125 vbus regulator compatible and constraints
    
Remove pm8150b fallback compatible from pm4125_vbus and fix regulator
constraints in qrb2210 DTS files to use microvolt instead of
microamp.

> diff --git a/arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts b/arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts
> --- a/arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts
> +++ b/arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts
[ ... ]
> @@ -235,8 +235,8 @@ &mdss_dsi0_phy {
>  };
>  
>  &pm4125_vbus {
> -	regulator-min-microamp = <500000>;
> -	regulator-max-microamp = <500000>;
> +	regulator-min-microvolt = <4250000>;
> +	regulator-max-microvolt = <5000000>;

[Severity: High]
This is a pre-existing issue, but does adding these voltage constraints now
trigger a hardware register corruption in the regulator driver?

Looking at the driver in drivers/regulator/qcom_usb_vbus-regulator.c,
PM4125_VBOOST_CFG is defined twice with different values:

drivers/regulator/qcom_usb_vbus-regulator.c:
    #define PM4125_VBOOST_CFG		0x52
    #define PM4125_VBOOST_CFG_MASK		GENMASK(1, 0)
    #define PM4125_VBOOST_CFG		0x56

Because of this shadowing, the pm4125_data struct initializes both .otg_cfg
and .vsel_reg to 0x56:

drivers/regulator/qcom_usb_vbus-regulator.c:
    .otg_cfg = PM4125_VBOOST_CFG,
    .otg_en_src_cfg = PM4125_OTG_EN_SRC_CFG,
    .vsel_reg = PM4125_VBOOST_CFG,

With the new regulator-min-microvolt constraints added by this device tree
change, the regulator core will now call .set_voltage_sel on this regulator.

Will this cause the driver to incorrectly write the voltage selector mask
to the OTG config register at 0x56 instead of the intended voltage selector
register at 0x52, thereby overwriting OTG configuration bits?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260701-add_pm4125-vbus-reg-v2-0-6bac2bac7131@oss.qualcomm.com?part=3