linux-kernel - Re: [PATCH 3/3] arm64: dts: qcom: x1e80100-qcp: Add WiFi/BT pwrseq

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Message-ID: <CAMRc=MfUEfKHkAVvtGODxvJ-BdL+kX7uDgW+1y4QW3Kc5mpX+w@mail.gmail.com>
Date: Thu, 17 Oct 2024 11:28:18 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Stephan Gerhold <stephan.gerhold@...aro.org>, Mark Brown <broonie@...nel.org>
Cc: Johan Hovold <johan@...nel.org>, 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, 
	Abel Vesa <abel.vesa@...aro.org>, Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH 3/3] arm64: dts: qcom: x1e80100-qcp: Add WiFi/BT pwrseq

On Wed, Oct 16, 2024 at 5:34 PM Stephan Gerhold
<stephan.gerhold@...aro.org> wrote:
>
> On Tue, Oct 15, 2024 at 02:27:56PM +0200, Johan Hovold wrote:
> > On Fri, Oct 11, 2024 at 12:11:43PM +0200, Stephan Gerhold wrote:
> > > On Thu, Oct 10, 2024 at 11:34:44AM +0200, Johan Hovold wrote:
> >
> > > > Based on our discussions it seems we do not really need to describe the
> > > > internal PMU at all for WCN7850 (as the bluetooth and wlan blocks can be
> > > > enabled indepdendently) so perhaps we can just restore the old binding
> > > > and drop most of this boilerplate for all boards.
> > > >
> > >
> > > I think there is no clear conclusion on that yet. The old bindings
> > > didn't describe any power supplies for WiFi at all. The pwrseq bindings
> > > are currently the only way to do that.
> > >
> > > We could potentially move all the "PMU supplies" to the WiFi/BT nodes
> > > and rely on reference counting to handle them. But I think it's better
> > > to wait how the M.2/generic PCI power control discussion turns out
> > > before investing any time to refactor the current solution.
> > >
> > > There are existing users of qcom,wcn7850-pmu already in 6.11, so I think
> > > it does not hurt to take this patch as-is for now. We can clean them up
> > > together later if needed.
> >
> > Sounds good.
> >
> > But can you please address the following warning that I see with this
> > series:
> >
> >       pwrseq-qcom_wcn wcn7850-pmu: supply vddio1p2 not found, using dummy regulator
> >
> > Not sure if it's the dtsi that's missing a supply if it's the driver
> > that needs fixing.
> >
>
> It's the driver, the DT should be correct. This supply exists on the
> WCN7850 chip, but nothing is connected there on the QCP.
>
> Unfortunately, it's not entirely straightforward to drop the warning
> since the pwrseq-qcom-wcn driver uses the bulk regulator APIs and
> (AFAIK) there is no good way to make only one of the regulators optional
> there.
>
> @Bartosz: Any thoughts on this? sm8550-qrd and sm8550-hdk are also
> missing the vddio1p2-supply, so they probably have the same warning in
> latest mainline.
>

How do others deal with it? I'm asking because I've been seeing these
warnings for years on many platforms which makes me think they are not
a high priority for anyone.

The best approach would be to provide an optional bulk get for the
regulator API. Or extend struct regulator_bulk_data with bool optional
and take this into account.

Mark: Any thoughts on this?

Bart