Re: [PATCH] arm64: dts: qcom: shikra-iqs-som: Correct PM8150 L10 voltage range

[Rakesh Kota]

On Tue, Sep 22, 2026 at 05:50:19PM +0200, Konrad Dybcio wrote:
> On 9/22/26 2:39 PM, Rakesh Kota wrote:
> > Update the PM8150 L10 regulator maximum voltage from 3.544 V to
> > 3.3 V, matching the supported voltage range for the Shikra IQS SoM.
> 
> This is a good start, but please mention explicitly what
> constitutes that range - is it e.g. because there are
> peripherals on that rail that can only sustain 3v3?
>

On Shikra IQS, the L10 rail supplies the SD card’s VMMC. Its maximum
voltage must be limited to 3.3 V because the derived VQMMC voltage on L2
supports up to approximately 3.3 V. Allowing VMMC to reach 3.544 V can
drive VQMMC beyond its supported range, potentially causing SD bus bit
errors and resulting in the voltage negotiation failure:

l2: unsupportable voltage range: 3500000-3296000uV

Reducing L10’s maximum voltage to 3.3 V keeps both rails within their
supported operating ranges.

regards
Rakesh Kota