Re: [PATCH v2 1/2] dt-bindings: usb: ti,hd3ss3220: Add support for VBUS based on ID state

[Krishna Kurapati PSSNV]

On 10/9/2025 8:08 PM, Dmitry Baryshkov wrote:
> On Thu, Oct 09, 2025 at 08:15:43AM -0500, Rob Herring wrote:
> > On Wed, Oct 08, 2025 at 09:31:59PM +0300, Dmitry Baryshkov wrote:
> > > On Wed, Oct 08, 2025 at 11:27:49PM +0530, Krishna Kurapati wrote:
> > > > Update the bindings to support reading ID state and VBUS, as per the
> > > > HD3SS3220 data sheet. The ID pin is kept high if VBUS is not at VSafe0V and
> > > > asserted low once VBUS is at VSafe0V, enforcing the Type-C requirement that
> > > > VBUS must be at VSafe0V before re-enabling VBUS.
> > > >
> > > > Add id-gpios property to describe the input gpio for USB ID pin and vbus-
> > > > supply property to describe the regulator for USB VBUS.
> > > >
> > > > Signed-off-by: Krishna Kurapati <krishna.kurapati@xxxxxxxxxxxxxxxx>
> > > > ---
> > > >   .../devicetree/bindings/usb/ti,hd3ss3220.yaml       | 13 +++++++++++++
> > > >   1 file changed, 13 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/usb/ti,hd3ss3220.yaml b/Documentation/devicetree/bindings/usb/ti,hd3ss3220.yaml
> > > > index bec1c8047bc0..c869eece39a7 100644
> > > > --- a/Documentation/devicetree/bindings/usb/ti,hd3ss3220.yaml
> > > > +++ b/Documentation/devicetree/bindings/usb/ti,hd3ss3220.yaml
> > > > @@ -25,6 +25,19 @@ properties:
> > > >     interrupts:
> > > >       maxItems: 1
> > > >   
> > > > +  id-gpios:
> > > > +    description:
> > > > +      An input gpio for USB ID pin. Upon detecting a UFP device, HD3SS3220
> > > > +      will keep ID pin high if VBUS is not at VSafe0V. Once VBUS is at VSafe0V,
> > > > +      the HD3SS3220 will assert ID pin low. This is done to enforce Type-C
> > > > +      requirement that VBUS must be at VSafe0V before re-enabling VBUS.
> > > > +
> > >
> > > Stray empty line?
> > >
> > > > +    maxItems: 1
> > > > +
> > > > +  vbus-supply:
> > > > +    description: A phandle to the regulator for USB VBUS if needed when host
> > > > +      mode or dual role mode is supported.
> > >
> > > Why are we adding the property here while we can use the vbus-supply of
> > > the usb-c-connector?
> >
> > Normally, that's my question on both of these, too. However, it does
> > look like both are connected to the chip. There's VBUS_DET which is
> > connected to Vbus (thru a 900k resistor). So having these here does look
> > like accurate representation of the h/w. The commit message should make
> > this more clear. Honestly, that's really the only part I care about.
> > How it works is not so important.
>
> The VBUS_DET pin is used by the controller to detect the VBUS provided
> by the USB-C partner and to identify when it's safe to turn on the
> device's VBUS supply. I think this still fits into the description of
> the connector's vbus-supply.


Hi Dmitry,

 In case we put the vbus supply in usb-c-connector node, is there any 
way we can get its phandle reference in hd3 driver given that the 
connector node is not a child or parent of port controller node.

Regards,
Krishna,