linux-kernel - Re: [PATCH v5 09/18] arm64: dts: qcom: qrb5165-rb5: model the PMU of the QCA6391

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Message-ID: <f72723f3-f5c5-4c16-a257-e5f57c4f9e73@sirena.org.uk>
Date: Tue, 20 Feb 2024 13:48:42 +0000
From: Mark Brown <broonie@...nel.org>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Marcel Holtmann <marcel@...tmann.org>,
	Luiz Augusto von Dentz <luiz.dentz@...il.com>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>, Kalle Valo <kvalo@...nel.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
	Saravana Kannan <saravanak@...gle.com>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Arnd Bergmann <arnd@...db.de>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Alex Elder <elder@...aro.org>,
	Srini Kandagatla <srinivas.kandagatla@...aro.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Abel Vesa <abel.vesa@...aro.org>,
	Manivannan Sadhasivam <mani@...nel.org>,
	Lukas Wunner <lukas@...ner.de>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	linux-bluetooth@...r.kernel.org, netdev@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-wireless@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-pci@...r.kernel.org,
	linux-pm@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v5 09/18] arm64: dts: qcom: qrb5165-rb5: model the PMU of
 the QCA6391

On Tue, Feb 20, 2024 at 02:38:33PM +0100, Bartosz Golaszewski wrote:
> On Tue, Feb 20, 2024 at 2:31 PM Mark Brown <broonie@...nel.org> wrote:
> > On Tue, Feb 20, 2024 at 12:16:10PM +0100, Bartosz Golaszewski wrote:

> > > And what do you mean by there not being any consumers? The WLAN and BT
> > > *are* the consumers.

> > There are no drivers that bind to the regulators and vary the voltages
> > at runtime.

> Even with the above misunderstanding clarified: so what? DT is the
> representation of hardware. There's nothing that obligates us to model
> DT sources in drivers 1:1.

It is generally a bad sign if there is a voltage range specified on a
regulator that's not got any indication that the voltage is going to be
actively managed, especially in situations like with several of the
supplies the DT was specifying where there are clear indications that
the supply is intended to be fixed voltage (or cases where every single
supply has a voltage range which would be highly unusual).  Looking at
the consumers might provide an explanation for such unusual and likely
incorrect constraints, and the lack of any consumers in conjunction with 
other warning signs reenforces those warning signs.

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