linux-kernel - Re: [PATCH v2] arm64: dts: qcom: x1e80100-qcp: Add WiFi/BT pwrseq

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Message-ID: <Z6uVJeQd1DXFFHG1@linaro.org>
Date: Tue, 11 Feb 2025 19:21:25 +0100
From: Stephan Gerhold <stephan.gerhold@...aro.org>
To: Bartosz Golaszewski <brgl@...ev.pl>
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 v2] arm64: dts: qcom: x1e80100-qcp: Add WiFi/BT pwrseq

On Tue, Feb 11, 2025 at 06:51:02PM +0100, Bartosz Golaszewski wrote:
> On Tue, Feb 11, 2025 at 4:49 PM Johan Hovold <johan@...nel.org> wrote:
> >
> > On Tue, Feb 11, 2025 at 04:01:56PM +0100, Stephan Gerhold wrote:
> > > Add the WiFi/BT nodes for QCP and describe the regulators for the WCN7850
> > > combo chip using the new power sequencing bindings. All voltages are
> > > derived from chained fixed regulators controlled using a single GPIO.
> > >
> > > The same setup also works for CRD (and likely most of the other X1E80100
> > > laptops). However, unlike the QCP they use soldered or removable M.2 cards
> > > supplied by a single 3.3V fixed regulator. The other necessary voltages are
> > > then derived inside the M.2 card. Describing this properly requires
> > > new bindings, so this commit only adds QCP for now.
> > >
> > > Signed-off-by: Stephan Gerhold <stephan.gerhold@...aro.org>
> > > ---
> > > Changes in v2:
> > > - Rebase on qcom for-next, patch 1-2 were applied already
> > > - Mention dummy regulator warning
> > > - Link to v1: https://lore.kernel.org/r/20241007-x1e80100-pwrseq-qcp-v1-0-f7166510ab17@linaro.org
> > > ---
> > > The Linux driver currently warns about a missing regulator supply:
> > >
> > >   pwrseq-qcom_wcn wcn7850-pmu: supply vddio1p2 not found, using dummy regulator
> > >
> > > This supply exists on the WCN7850 chip, but nothing is connected there on
> > > the QCP. Discussion is still open how to hide this warning in the driver,
> > > but since the DT is correct and the same setup is already used on SM8550
> > > upstream, this shouldn't block this patch.
> >
> > I thought Bartosz was gonna fix his driver...
> >
> 
> This is not the same issue. The one you're thinking about[1] was fixed
> by commit ad783b9f8e78 ("PCI/pwrctl: Abandon QCom WCN probe on
> pre-pwrseq device-trees").
> 
> This warning comes from the PMU driver, not the PCI pwrctrl one for
> the WLAN module. One solution would be to make this supply optional in
> bindings and use regulator_get_optional for the ones we know may be
> unconnected. Does it sound correct?
> 

The supply is optional already in the bindings. It's not optional in the
driver though, because that one uses the bulk regulator API and that
currently provides no way to mark an individual regulator as optional.

We did discuss this on v1 of this patch. I think you did not get back to
Mark's last message yet [2]. :-)

Thanks,
Stephan

[2]: https://lore.kernel.org/linux-arm-msm/f125c7d5-5f85-4ff6-999b-2098ff3103f9@sirena.org.uk/