linux-kernel - Re: [PATCH RFC] arm64: dts: qcom: x1e80100: Fix USB combo PHYs SS1 and SS2 ref clocks

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Message-ID: <70c2f5ba-df98-4ec0-a420-915bbc65eaef@oss.qualcomm.com>
Date: Tue, 4 Nov 2025 13:36:42 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Abel Vesa <abel.vesa@...aro.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>,
        Rajendra Nayak <quic_rjendra@...cinc.com>,
        Sibi Sankar <sibi.sankar@....qualcomm.com>
Cc: Taniya Das <taniya.das@....qualcomm.com>,
        Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC] arm64: dts: qcom: x1e80100: Fix USB combo PHYs SS1
 and SS2 ref clocks

On 11/3/25 5:51 PM, Abel Vesa wrote:
> It seems the USB combo SS1 and SS2 ref clocks have another gate, unlike
> the SS0. These gates are part of the TCSR clock controller.

FWIW this is a conscious design choice

> 
> At least on Dell XPS 13 (9345), if the ref clock provided by the TCSR
> clock controller for SS1 PHY is disabled on the clk_disable_unused late
> initcall, the PHY fails to initialize. It doesn't happen on the SS0 PHY
> and the SS2 is not used on this device.
> 
> This doesn't seem to be a problem on CRD though. It might be that the
> RPMh has a vote for it from some other consumer and does not actually
> disable it when ther kernel drops its vote.
> 
> Either way, these TCSR provided clocks seem to be the correct ones for
> the SS1 and SS2, so use them instead.
> 
> Fixes: 4af46b7bd66f ("arm64: dts: qcom: x1e80100: Add USB nodes")
> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Konrad