Re: [PATCH v3 7/9] regulator: mt6392: Add support for MT6392 regulator

[Chen-Yu Tsai]

On Mon, Mar 30, 2026 at 3:39 PM Luca Leonardo Scorcia
<l.scorcia@xxxxxxxxx> wrote:
>
> Il giorno gio 19 mar 2026 alle ore 06:04 Chen-Yu Tsai
> <wenst@xxxxxxxxxxxx> ha scritto:
>
> > If this PMIC is anything like the MT6358, then it has 0.01V fine
> > tuning for most if not all the LDOs. It is sometimes needed as
> > a rail may have a 0.04V boost that would otherwise be invisible
> > to the system. And then if you have something like 3.04V set in
> > the DT constraints, you end up with something the regulator driver
> > doesn't support, but the hardware does.
> >
> > Please see how it's done in the MT6358 driver. I spent a lot of
> > time on that driver to make it actually support the full range
> > of voltages, and describing the supplies.
> >
>
> I had a good look at the datasheet (MT6392 PMIC Datasheet v1.0 08 Dec.
> 2016) and unfortunately I did not see any fine tuning option in there.
> I'm sure this data sheet is not perfect as it's missing some regulator
> registers that are clearly used in the Android sources, but there's no
> mention of fine tuning in that code either. I guess it does not have
> that capability.

Well, thanks for looking. FWIW on the MT6358 / MT6366, the main voltage
control and the fine tuning are mostly in the same register. The fine
tuning is described as "calibrates output voltage" from +00mV to +100mV.

I looked into this because the LDO table shows some of the default voltages
with 0.01V precision, but the main voltage controls only have 0.1V precision.


ChenYu

> I will shortly submit v4 that hopefully addresses the rest of the comments.
>
> Thanks for your help!
> --
> Luca Leonardo Scorcia
> l.scorcia@xxxxxxxxx