linux-kernel - Re: [PATCH v2] arm64: dts: qcom: hamoa-iot-evk: Add vbus regulator support for Type-A ports

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Message-ID: <elzlkxhjd7oqfs43dpsvxqavrdr4564sxdkshnlz5artdb2sp5@7dt3eexoitbl>
Date: Tue, 9 Dec 2025 17:54:24 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Krishna Kurapati <krishna.kurapati@....qualcomm.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Subject: Re: [PATCH v2] arm64: dts: qcom: hamoa-iot-evk: Add vbus regulator
 support for Type-A ports

On Tue, Dec 09, 2025 at 09:01:02PM +0530, Krishna Kurapati wrote:
> 
> 
> On 12/9/2025 8:49 PM, Dmitry Baryshkov wrote:
> > On Tue, Dec 09, 2025 at 01:31:10PM +0530, Krishna Kurapati wrote:
> > > 
> > > 
> > > On 12/9/2025 1:22 PM, Dmitry Baryshkov wrote:
> > > > On Tue, Dec 09, 2025 at 09:47:01AM +0530, Krishna Kurapati wrote:
> > > > > The Multiport controller on Hamoa EVK platform is connected to Two Type-A
> > > > > ports. VBUS for each of these ports are provided by a TPS2559QWDRCTQ1
> > > > > regulator, controlled from PMIC GPIOs.
> > > > > 
> > > > > Add the necessary regulators and GPIO configuration to power these.
> > > > 
> > > > Should this also include corresponding USB-A connector devices? See
> > > > qcs6490-radxa-dragon-q6a.dts for the example of how to describe them.
> > > > 
> > > 
> > > Hi Dmitry,
> > > 
> > >   I see same discussion that came up when we were trying to upstream TypeA
> > > connectors of SA8295:
> > > 	
> > > https://lore.kernel.org/all/CAA8EJppf+j6H8vPOrer1Oj6SuM=qHKXoBahtCaCr7an-cbpyOQ@mail.gmail.com/
> > > 
> > > There is no entity (either phy or dwc3) as of today that can read the vbus
> > > from connector-A node and use it. So keeping these regulators always on for
> > > now.
> > 
> > There are two distinct questions:
> > - one is how you describe the board and onboard devices / connectors
> > - another one is how to make sure VBus is enabled.
> > 
> > I'd suggest having full description (with connectors, graph links
> > between USB host and connector and vbus-supply properties) and then
> > having the comment before regulator-always-on describing why it's on.
> > 
> 
> Thanks for the review Dmitry. So, IIUC, the suggestion is to add the
> connector nodes for Type-A ports, add the vbus in the connector and mark the
> vbus regulator nodes as always ON.
> 
> W.r.t the graph nodes, we can't link the connector to any available node
> today. Can we leave the remote endpoints empty and unlinked to anything.

Sure you can link them. Both DWC3 and PHY define corresponding HS and SS
streams. If not, you can fix them.

-- 
With best wishes
Dmitry