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From:   Rob Herring <robh@kernel.org>
Date:   Fri, 30 Oct 2020 09:29:28 -0500
Message-ID: <CAL_JsqKs-Po8BdShjQNDNPjNWBCD3FSPdq4KbQGx3=VnV+3nPw@mail.gmail.com>
Subject: Re: [RESEND PATCH v3 1/4] dt-bindings: connector: add power-opmode
 optional property to usb-connector
To:     Amelie DELAUNAY <amelie.delaunay@st.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Russell King <linux@armlinux.org.uk>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux USB List <linux-usb@vger.kernel.org>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-stm32@st-md-mailman.stormreply.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Fabrice Gasnier <fabrice.gasnier@st.com>
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On Thu, Oct 29, 2020 at 11:49 AM Amelie DELAUNAY <amelie.delaunay@st.com> wrote:
>
>
>
> On 10/29/20 4:40 PM, Rob Herring wrote:
> > On Thu, Oct 29, 2020 at 10:58:03AM +0100, Amelie Delaunay wrote:
> >> Power operation mode may depends on hardware design, so, add the optional
> >> property power-opmode for usb-c connector to select the power operation
> >> mode capability.
> >>
> >> Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
> >> ---
> >>   .../bindings/connector/usb-connector.yaml      | 18 ++++++++++++++++++
> >>   1 file changed, 18 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
> >> index 728f82db073d..200d19c60fd5 100644
> >> --- a/Documentation/devicetree/bindings/connector/usb-connector.yaml
> >> +++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
> >> @@ -93,6 +93,24 @@ properties:
> >>         - device
> >>         - dual
> >>
> >> +  power-opmode:
> >
> > I've acked this version:
> >
> > https://lore.kernel.org/r/20201020093627.256885-2-badhri@google.com
> >
>
> frs is used for Fast Role Swap defined in USB PD spec.
> I understand it allows to get the same information but I'm wondering why
> the property name is limited to -frs- in this case. What about a
> non-power delivery USB-C connector ?

I've got no idea. The folks that know USB-C and PD details need to get
together and work all this out. To me, it looks like the same thing...

And it's not just this, but the stream of USB-C additions that trickle in.

> Moreover, power-opmode property support is already merged in typec class:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/usb/typec/class.c?h=v5.10-rc1&id=12f3467b0d28369d3add7a0deb65fdac9b503c90
> and stusb160x driver uses it :(
>
> So, do I need to modify stusb160x driver (and bindings) to take into
> account this USB PD specific property?

If not documented, then it's not an ABI, so yes.

Rob