linux-kernel - Re: [PATCH 2/3] arm64: dts: qcom: sc8280xp: Correct USB PHY power domains

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Message-ID: <ZY7I1brn0chtOzis@hovoldconsulting.com>
Date: Fri, 29 Dec 2023 14:25:41 +0100
From: Johan Hovold <johan@...nel.org>
To: Konrad Dybcio <konrad.dybcio@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Johan Hovold <johan+linaro@...nel.org>,
	Marijn Suijten <marijn.suijten@...ainline.org>,
	linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Konrad Dybcio <konrad.dybcio@...ainline.org>
Subject: Re: [PATCH 2/3] arm64: dts: qcom: sc8280xp: Correct USB PHY power
 domains

[ Please remember to trim your replies and add a newline before your
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On Fri, Dec 29, 2023 at 02:06:26PM +0100, Konrad Dybcio wrote:
> On 29.12.2023 14:01, Johan Hovold wrote:
> > On Wed, Dec 27, 2023 at 11:28:27PM +0100, Konrad Dybcio wrote:

> >> Fix the power-domains assignment to stop potentially toggling the GDSC
> >> unnecessarily.
> > 
> > Again, there's no additional toggling being done here, but yes, this may
> > keep the domains enabled during suspend depending on how the driver is
> > implemented.

> No, it can actually happen. (Some) QMP PHYs are referenced by the
> DP hardware. If USB is disabled (or suspended), the DP being active
> will hold these GDSCs enabled.

That's not a "toggling", is it? Also if the DP controller is a consumer of
these PHY's why should it not prevent the PHYs from suspending?

Johan