Re: [PATCH v6 3/4] regulator: qcom-rpmh: readback voltage/bypass/mode set during bootup

[Kamal Wadhwa]

On Tue, Sep 01, 2026 at 11:49:42AM +0200, Konrad Dybcio wrote:
> On 8/1/26 10:00 AM, Kamal Wadhwa wrote:
> > Currently, during regulator registration, regulator framework sends an
> > unnecessary `min-microvolts` request for the rpmh-regulator device. This
> > happens because in current design, we do not have a way to readback the
> > voltage settings that was set during the bootloader stage.
> > 
> > Fix this by using the rpmh_read() API to read the regulator voltage
> > settings done during boot and make it available to regulator framework
> > from the very first read after the bootup.
> > 
> > Also use this API to read the mode/bypass settings as well. This will
> > provide the regulator framework a sense of the initial settings done by
> > bootloader and thus preventing any redundant writes for any setting post
> > bootup incase the same setting was already applied during bootup.
> > 
> > Signed-off-by: Kamal Wadhwa <kamal.wadhwa@xxxxxxxxxxxxxxxx>
> > ---
> 
> SC8180X Primus hangs with this patch applied and so does SM8150 HDK.

Ok, i did see some issues on SM8550 but those were mainly related to the
voltage range check leading to some regulator failing to probe, for that
this below change may help.
https://lore.kernel.org/all/20260720-b4-regulator-core-clamp-voltage-v1-1-8e5eec076a8e@xxxxxxxxxxxxxxxx/

But i suppose you may already have it?

do you see the problem with the rpmh_read() or in the voltage range check?

> 
> Interestingly, SDM845 DB845c doesn't
> 
> I think we may need to opt some platforms out of this..
> 
> Konrad