linux-kernel - Re: [PATCH v3 3/4] dt-bindings: usb: microchip,usb2514: add support for port vbus-supply

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Message-ID: <20250822103005.c7ba7dclbgdadyw7@pengutronix.de>
Date: Fri, 22 Aug 2025 12:30:05 +0200
From: Marco Felsch <m.felsch@...gutronix.de>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Fabio Estevam <festevam@...il.com>,
	Matthias Kaehlcke <mka@...omium.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	kernel@...gutronix.de
Subject: Re: [PATCH v3 3/4] dt-bindings: usb: microchip,usb2514: add support
 for port vbus-supply

On 25-08-22, Krzysztof Kozlowski wrote:
> On Thu, Aug 21, 2025 at 06:31:57PM +0200, Marco Felsch wrote:
> > Some PCB designs don't connect the USB hub port power control GPIO and
> > instead make use of a host controllable regulator. Add support for this
> > use-case by introducing portX-vbus-supply property.
> > 
> > Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> > ---
> >  Documentation/devicetree/bindings/usb/microchip,usb2514.yaml | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/usb/microchip,usb2514.yaml b/Documentation/devicetree/bindings/usb/microchip,usb2514.yaml
> > index 4e3901efed3fcd4fbbd8cb777f9df4fcadf2ca00..ac1e5f1a5ea2e66c61ce92154385952b15e78e55 100644
> > --- a/Documentation/devicetree/bindings/usb/microchip,usb2514.yaml
> > +++ b/Documentation/devicetree/bindings/usb/microchip,usb2514.yaml
> > @@ -49,6 +49,12 @@ patternProperties:
> >      $ref: /schemas/usb/usb-device.yaml
> >      additionalProperties: true
> >  
> > +  "^port[1-7]-vbus-supply$":
> > +    type: object
> > +    description:
> > +      Regulator controlling the USB VBUS on portX. Only required if the host
> > +      controls the portX VBUS.
> 
> Your commit msg should briefly describe status of previous discussion:
> why Rob's comment was not applied. Otherwise we repeat: this looks like
> property of specific port.

I answered Rob on my v1 but got no feedback. My v2 caused an issue found
by Rob's test bot. Therefore I thought he is okay and applied the
patchset for testing.

At least to me it's unclear when Rob's test bot is executed.

> The binding does not list ports now, but lists hard-wired devices, so my
> question is now: is this per hard-wired device or per port (even if port
> is hot-pluggable)?

Sorry but I don't get you. The binding lists the regulators required to
enable/disable the hub downstream port VBUS. These regulators are
controlled by an external party e.g. the CPU instead of the USB hub
itself. The connection from the CPU to the regulator which controlls the
+5V usb-connector pin is hard-wired, yes.

Regards,
  Marco