linux-kernel - Re: [PATCH v3 07/20] dt-bindings: firmware: google,gs101-acpm-ipc: update PMIC examples

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Message-ID: <fa2e704a2f295f2c9b2c7811e8ca89972554ff7e.camel@linaro.org>
Date: Sat, 08 Nov 2025 14:08:52 +0000
From: André Draszik <andre.draszik@...aro.org>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: Tudor Ambarus <tudor.ambarus@...aro.org>, Rob Herring <robh@...nel.org>,
  Conor Dooley <conor+dt@...nel.org>, Liam Girdwood <lgirdwood@...il.com>,
 Mark Brown <broonie@...nel.org>,  Lee Jones <lee@...nel.org>, Linus Walleij
 <linus.walleij@...aro.org>, Bartosz Golaszewski	 <brgl@...ev.pl>, Krzysztof
 Kozlowski <krzk+dt@...nel.org>, Peter Griffin	 <peter.griffin@...aro.org>,
 Will McVicker <willmcvicker@...gle.com>, 	kernel-team@...roid.com,
 linux-kernel@...r.kernel.org, 	linux-samsung-soc@...r.kernel.org,
 devicetree@...r.kernel.org, 	linux-gpio@...r.kernel.org
Subject: Re: [PATCH v3 07/20] dt-bindings: firmware: google,gs101-acpm-ipc:
 update PMIC examples

Hi Krzysztof,

Thanks for your review!

On Tue, 2025-11-04 at 09:31 +0100, Krzysztof Kozlowski wrote:
> On Mon, Nov 03, 2025 at 07:14:46PM +0000, André Draszik wrote:
> > In a typical system using the Samsung S2MPG10 PMIC, an S2MPG11 is used
> > as a sub-PMIC.
> > 
> > The interface for both is the ACPM firmware protocol, so update the
> > example here to describe the connection for both.
> > 
> > Signed-off-by: André Draszik <andre.draszik@...aro.org>
> > ---
> >  .../bindings/firmware/google,gs101-acpm-ipc.yaml   | 40 ++++++++++++++++++++--
> >  1 file changed, 37 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/firmware/google,gs101-acpm-ipc.yaml
> > b/Documentation/devicetree/bindings/firmware/google,gs101-acpm-ipc.yaml
> > index 4a1e3e3c0505aad6669cadf9b7b58aa4c7f284cb..c25e155926e5f44bd74f195cdbff3672c7499f8e 100644
> > --- a/Documentation/devicetree/bindings/firmware/google,gs101-acpm-ipc.yaml
> > +++ b/Documentation/devicetree/bindings/firmware/google,gs101-acpm-ipc.yaml
> > @@ -45,6 +45,15 @@ properties:
> >        compatible:
> >          const: samsung,s2mpg10-pmic
> >  
> > +  pmic2:
> 
> pmic-2
> 
> Are there more pmics? Bindings are supposed to be complete (see writing
> bindings) and if you did follow this approach earlier, you would nicely
> call first "pmic-1" (instead of "pmic") and then "pmic-2".

There aren't any more PMICs on ACPM, no. At the time 'pmic' was added, it wasn't clear
unfortunately that two nodes would be needed in the end.

See also https://lore.kernel.org/all/963bbf8db71efc0d729bb9141c133df2c56881fc.camel@linaro.org/

That said, I believe we can change the existing node name from pmic to pmic-1 without
any driver breaking. The sysfs path would change, but I don't think anybody cares about
it at this stage, so I think such a change would be fine. The ACPM driver doesn't care
about node names and instantiates all children regardless of name.

I propose to update the binding (and DTS subsequently) to add pmic-1, to allow 'pmic' as
a legacy fallback (i.e. to not issue errors during validation of existing DTSs until
they're updated) and to use pmic-2 for the 2nd pmic.

OK?


Cheers,
Andre'