linux-kernel - Re: [PATCH v3 0/3] phy: qcom: edp: Add missing ref clock to x1e80100

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Message-ID: <qohctzmztibeoy4jv6unsvevdawfh2h3drrneo5wmbfkirokog@pfaz3vht5kjz>
Date: Fri, 19 Sep 2025 14:54:34 +0300
From: Abel Vesa <abel.vesa@...aro.org>
To: Xilin Wu <sophon@...xa.com>
Cc: Vinod Koul <vkoul@...nel.org>, 
	Kishon Vijay Abraham I <kishon@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Bjorn Andersson <andersson@...nel.org>, Dmitry Baryshkov <lumag@...nel.org>, 
	Konrad Dybcio <konradybcio@...nel.org>, Sibi Sankar <quic_sibis@...cinc.com>, 
	Rajendra Nayak <quic_rjendra@...cinc.com>, Johan Hovold <johan@...nel.org>, 
	Taniya Das <quic_tdas@...cinc.com>, Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>, 
	linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v3 0/3] phy: qcom: edp: Add missing ref clock to x1e80100

On 25-09-19 19:06:36, Xilin Wu wrote:
> On 9/9/2025 3:33 PM, Abel Vesa wrote:
> > According to documentation, the DP PHY on x1e80100 has another clock
> > called ref.
> > 
> > The current X Elite devices supported upstream work fine without this
> > clock, because the boot firmware leaves this clock enabled. But we should
> > not rely on that. Also, when it comes to power management, this clock
> > needs to be also disabled on suspend. So even though this change breaks
> > the ABI, it is needed in order to make we disable this clock on runtime
> > PM, when that is going to be enabled in the driver.
> > 
> > So rework the driver to allow different number of clocks, fix the
> > dt-bindings schema and add the clock to the DT node as well.
> > 
> > Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> > ---
> > Changes in v3:
> > - Use dev_err_probe() on clocks parsing failure.
> > - Explain why the ABI break is necessary.
> > - Drop the extra 'clk' suffix from the clock name. So ref instead of
> >    refclk.
> > - Link to v2: https://lore.kernel.org/r/20250903-phy-qcom-edp-add-missing-refclk-v2-0-d88c1b0cdc1b@linaro.org
> > 
> > Changes in v2:
> > - Fix schema by adding the minItems, as suggested by Krzysztof.
> > - Use devm_clk_bulk_get_all, as suggested by Konrad.
> > - Rephrase the commit messages to reflect the flexible number of clocks.
> > - Link to v1: https://lore.kernel.org/r/20250730-phy-qcom-edp-add-missing-refclk-v1-0-6f78afeadbcf@linaro.org
> > 
> > ---
> > Abel Vesa (3):
> >        dt-bindings: phy: qcom-edp: Add missing clock for X Elite
> >        phy: qcom: edp: Make the number of clocks flexible
> >        arm64: dts: qcom: Add missing TCSR ref clock to the DP PHYs
> > 
> >   .../devicetree/bindings/phy/qcom,edp-phy.yaml      | 28 +++++++++++++++++++++-
> >   arch/arm64/boot/dts/qcom/x1e80100.dtsi             | 12 ++++++----
> >   drivers/phy/qualcomm/phy-qcom-edp.c                | 16 ++++++-------
> >   3 files changed, 43 insertions(+), 13 deletions(-)
> > ---
> > base-commit: 65dd046ef55861190ecde44c6d9fcde54b9fb77d
> > change-id: 20250730-phy-qcom-edp-add-missing-refclk-5ab82828f8e7
> > 
> > Best regards,
> 
> Hi,
> 
> I'm observing what looks like a related clock failure on sc8280xp when
> booting without a monitor connected to a DP-to-HDMI bridge on mdss0_dp2.

Am I to understand that this is triggered by this patchset ?

I don't see how though.

> 
> Do you think sc8280xp might require a similar fix, or could this be a
> different issue?

There is no TCSR clock controller on sc8280xp, so it must be something
else. My feeling is that this is probably triggered by the link clock
source not being parented to the clock generated by the PHY, or PHY PLL
isn't locked yet at that point, but I'm not sure.

I'm not able to reproduce this issue on my x13s.