linux-kernel - Re: [PATCH 1/2] phy: qcom: phy-qcom-snps-eusb2: Make repeater optional

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Message-ID: <Z9qd1GJ1418CbaOt@linaro.org>
Date: Wed, 19 Mar 2025 11:35:00 +0100
From: Stephan Gerhold <stephan.gerhold@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	Ivaylo Ivanov <ivo.ivanov.ivanov1@...il.com>,
	bjorn.andersson@....qualcomm.com
Cc: Vinod Koul <vkoul@...nel.org>,
	Kishon Vijay Abraham I <kishon@...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>,
	Aleksandrs Vinarskis <alex.vinarskis@...il.com>,
	linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH 1/2] phy: qcom: phy-qcom-snps-eusb2: Make repeater
 optional

On Wed, Mar 19, 2025 at 12:20:07PM +0200, Dmitry Baryshkov wrote:
> On Tue, Mar 18, 2025 at 10:22:56PM -0500, Bjorn Andersson via B4 Relay wrote:
> > From: Bjorn Andersson <bjorn.andersson@....qualcomm.com>
> > 
> > In a multiport configuration based on the SNPS eUSB2 PHY it's not
> > necessary that all ports are connected to something.
> > 
> > While this is allowed by the Devicetree binding, the implementation
> > current fails probing for such PHYs, which also prevents the multiport
> > controller from probing.
> > 
> > The lack of repeater does not alter the fact that the PHY is there and
> > attempts at describing only the used PHYs in Devicetree results in
> > failures to initialize the USB controller.
> > 
> > Make the repeater optional, to allow the these PHYs to be described in
> > the DeviceTree and for the associated multiport controller to operate
> > the other ports.
> > 
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@....qualcomm.com>
> > ---
> >  drivers/phy/qualcomm/phy-qcom-snps-eusb2.c | 10 +++++++---
> >  1 file changed, 7 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/phy/qualcomm/phy-qcom-snps-eusb2.c b/drivers/phy/qualcomm/phy-qcom-snps-eusb2.c
> > index 1484691a41d59a7eaf257ef44300827c668bf7e0..8897d2072ccfcaa5b4a510c17761dcdeed5bad0f 100644
> > --- a/drivers/phy/qualcomm/phy-qcom-snps-eusb2.c
> > +++ b/drivers/phy/qualcomm/phy-qcom-snps-eusb2.c
> > @@ -401,9 +401,13 @@ static int qcom_snps_eusb2_hsphy_probe(struct platform_device *pdev)
> >  				     "failed to get regulator supplies\n");
> >  
> >  	phy->repeater = devm_of_phy_get_by_index(dev, np, 0);
> > -	if (IS_ERR(phy->repeater))
> > -		return dev_err_probe(dev, PTR_ERR(phy->repeater),
> > -				     "failed to get repeater\n");
> > +	if (IS_ERR(phy->repeater)) {
> > +		if (PTR_ERR(phy->repeater) == -ENODEV)
> > +			phy->repeater = NULL;
> > +		else
> > +			return dev_err_probe(dev, PTR_ERR(phy->repeater),
> > +					     "failed to get repeater\n");
> 
> Can you use devm_of_phy_optional_get() or devm_phy_optional_get()
> instead?
> 

There is such a patch from Ivaylo already [1].

@Ivaylo: Are you planning to re-spin that patch set? Might be even worth
putting that patch first / sending it separately, since Neil pointed out
there that the bindings already have the repeater as non-required.

Thanks,
Stephan

[1]: https://lore.kernel.org/linux-arm-msm/20250223122227.725233-6-ivo.ivanov.ivanov1@gmail.com/