linux-kernel - Re: [PATCH 14/24] arm64: dts: qcom: Update the pmh0110.dtsi for Glymur

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Message-ID: <20251008073123.GA20592@hu-kamalw-hyd.qualcomm.com>
Date: Wed, 8 Oct 2025 13:01:23 +0530
From: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Krzysztof Kozlowski <krzk@...nel.org>,
        Pankaj Patil <pankaj.patil@....qualcomm.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 14/24] arm64: dts: qcom: Update the pmh0110.dtsi for
 Glymur

Hi Krzysztof, Dmitry, Konrad,

On Thu, Sep 25, 2025 at 09:57:02PM +0300, Dmitry Baryshkov wrote:
> On Thu, Sep 25, 2025 at 10:34:52PM +0900, Krzysztof Kozlowski wrote:
> > On Thu, 25 Sept 2025 at 22:14, Dmitry Baryshkov
> > <dmitry.baryshkov@....qualcomm.com> wrote:
> > >
> > > On Thu, Sep 25, 2025 at 05:08:54PM +0900, Krzysztof Kozlowski wrote:
> > > > On Thu, 25 Sept 2025 at 15:34, Pankaj Patil
> > > > <pankaj.patil@....qualcomm.com> wrote:
> > > > >
> > > > > From: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
> > > > >
> > > > > Add multiple instance of PMH0110 DT node, one for each assigned
> > > > > SID for this PMIC on the spmi_bus0 and spmi_bus1 on the Glymur
> > > > > CRD.
> > > > >
> > > > > Take care to avoid compilation issue with the existing nodes by
> > > > > gaurding each PMH0110 nodes with `#ifdef` for its corresponding
> > > > > SID macro. So that only the nodes which have the their SID macro
> > > > > defined are the only ones picked for compilation.
> > > > >
> > > > > Signed-off-by: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
> > > > > Signed-off-by: Pankaj Patil <pankaj.patil@....qualcomm.com>
> > > > > ---
> > > > >  arch/arm64/boot/dts/qcom/pmh0110.dtsi | 66 ++++++++++++++++++++++++++++++++++-
> > > > >  1 file changed, 65 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/arch/arm64/boot/dts/qcom/pmh0110.dtsi b/arch/arm64/boot/dts/qcom/pmh0110.dtsi
> > > > > index b99c33cba8860f1852231db33a127646c08c1e23..4a5c66e5c9fbc35cedb67601f4568844dc41fbea 100644
> > > > > --- a/arch/arm64/boot/dts/qcom/pmh0110.dtsi
> > > > > +++ b/arch/arm64/boot/dts/qcom/pmh0110.dtsi
> > > > > @@ -7,6 +7,8 @@
> > > > >  #include <dt-bindings/spmi/spmi.h>
> > > > >
> > > > >  &spmi_bus0 {
> > > > > +
> > > > > +#ifdef PMH0110_D_E0_SID
> > > >
> > > > NAK
> > > >
> > > > I already explained on IRC in great details why.
> > >
> > > A short summary or a link to a channel / date would be nice in order to
> > > include other people into the discussion.
> > >
> > 
> > Of course but:
> > 1. You were there so maybe you remember the arguments, and:
> > 2. I'm offline, using phone, not having laptop, replying during my
> > personal time off just before merge window so any emergency time
> > should be spent on important matters instead these two huge patch
> > bombs adding such usage I already said: NO, don't do this.
> 
> 
> Well, If I'm asking, it means I don't rememebr the discussion. And I
> defeinitely didn't know that you are spending your personal vacation
> time in ML. And if the discussion was with some other people, then
> somebody else can drop the response to the question.

Just wanted to give some background on this patch.
Even though PMH0104 and PMH0110 are common (b/w Kaanapali and Glymur),
they don't share the SIDs. So we tried to use status="disabled" to handle
this but we observed that because of the node name being common in the
two included files, it ends up overwriting the previous node with the
same name.

eg-
#include "pmh0104.dtsi"  // assume contains pmic@4 { ...};
#include "pmh0110.dtsi"  // assume contains pmic@4 { status=disabled;};

Here intention was to use the pmh0104 on sid-4, but it gets overwritten
with the pmh0110 on sid-4 ( with status disabled). This is why we ended
up using the `#ifdef`, ensuring that we can control the exact pmic that
gets picked by using the PMXXX_SID macro.

side note, i did `grep` in the `/arch/arm64/boot/dts/` and i see a lot
of instances of `#if...` present in that.  Assuming the concern here is
about the use of `#ifdef`.

Can you suggest some alternative approach?
or comment on below approaches:-

1. Can I use `pmic@...104_d_e0` ?
This may work but looks like a departure from the current format
i.e `pmic@<sid>` used in the arch/arm64/boot/dts/qcom.

2. Create PMIC-ID based pmic dts? `pmh0104_d_e0.dtsi` and likewise add all
pmics? But this could mean creating too many pmic files and end up
bloating the dts/qcom/ directory.

3. Add the nodes directly inside glymur-pmics.dtsi ( not using #include)?
It may make the file too long and IMO it may take slightly more time, to
look at the file and tell what PMICs are present and at what SID.

Please share if you prefer any of the above suggestions? or a completely
different approach to get around this. ( or if the current NAK'ed patch
can somehow be improved still? or share link for old discussion so i can
study it)

Would value any advice that you can share. Thanks in advance!

> 
> -- 
> With best wishes
> Dmitry

Regards,
Kamal