Re: [PATCH v4 2/2] arm64: dts: qcom: Add Xiaomi 12 Lite 5G (taoyao) DTS

[Stanislav Zaikin <zstaseg@gmail.com>]

On 3/16/26 5:05 AM, Val Packett wrote:
> On 3/5/26 6:39 AM, Stanislav Zaikin wrote:
>
>> Xiaomi 12 Lite 5G is a handset released in 2022
>>
>> This commit has the following features working:
>> - Display (with simple fb)
>> - Touchscreen
>> - UFS
>> - Power and volume buttons
>> - Pinctrl
>> - RPM Regulators
>> - Remoteprocs - wifi, bluetooth
>> - USB (Device Mode)
>> […]
>> +        vreg_l7b_2p96: ldo7 {
>> +            regulator-name = "vreg_l7b_2p96";
>> +            /* Constrained for UFS VCC, at least until UFS driver 
>> scales voltage */
>> +            regulator-min-microvolt = <2952000>;
>> +            regulator-max-microvolt = <2952000>;
>> +            regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
>> +        };
>> […]
>> +&ufs_mem_hc {
>> +    reset-gpios = <&tlmm 175 GPIO_ACTIVE_LOW>;
>> +
>> +    vcc-supply = <&vreg_l7b_2p96>;
>> +    vcc-max-microamp = <800000>;
>> +    /*
>> +     * Technically l9b enables an eLDO (supplied by s1b) which then 
>> powers
>> +     * VCCQ2 of the UFS.
>> +     */
>> +    vccq-supply = <&vreg_l9b_1p2>;
>> +    vccq-max-microamp = <900000>;
>
> If this device has UFS 3.x flash, which it most likely does, the 
> copy-pasted eLDO comment does not apply.. and VCC range is 2.4V-2.7V, 
> 2.95 is overvoltage! 

Hello Val,

Thank you for the review.

Though you're right that this comment is a copy-paste, taoyao has ufs2. 
This is the explaining comment from the downstream sources:

> /*
> * Yupik target supports both UFS2.2 & UFS3.1, here
> * vccq2 is supplied via eLDO, and that is controlled via
> * L9B which supports a max voltage of 1.2V, but eLDO would
> * supply 1.8V. and same L9B acts as vccq voltage for UFS3.1
> * devices.
> * Here L9B can max support for 1.2V but UFS GKI driver code
> * votes for 1.8V, which is leading to failure from pmic
> * regulator.
> *
> * Now since vccq and control of eLDO are common that is L9B
> * we can use vccq vote as control of eLDO for vccq2.
> * Hence vccq entries shall be used for both type of UFS
> * devices only. And vccq entries should not be changed/removed
> * for any design alteration.
> */

So I thought it's better to keep a small comment regarding eLDO.

> If it's actually UFS 2 after all, it would be better to rename the 
> property to vccq2-supply.
Could you elaborate please? Do you mean l9b?