linux-kernel - Re: [PATCH RFC 2/2] usb: typec: Add support for Parade PS8830 Type-C Retimer

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Message-ID: <CAA8EJpqq9ROYyTnwPwj+mX2T_422vcmcyzPta+QPL53EgtJ6vg@mail.gmail.com>
Date: Mon, 23 Sep 2024 18:03:09 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abel Vesa <abel.vesa@...aro.org>
Cc: Johan Hovold <johan@...nel.org>, Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 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>, 
	Rajendra Nayak <quic_rjendra@...cinc.com>, Sibi Sankar <quic_sibis@...cinc.com>, 
	Trilok Soni <quic_tsoni@...cinc.com>, linux-kernel@...r.kernel.org, 
	linux-usb@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH RFC 2/2] usb: typec: Add support for Parade PS8830 Type-C Retimer

On Mon, 23 Sept 2024 at 17:41, Abel Vesa <abel.vesa@...aro.org> wrote:
>
> On 24-09-04 15:20:55, Johan Hovold wrote:
> > On Tue, Sep 03, 2024 at 09:27:45AM +0200, Johan Hovold wrote:
> > > On Thu, Aug 29, 2024 at 09:44:26PM +0300, Abel Vesa wrote:
> > > > The Parade PS8830 is a Type-C muti-protocol retimer controlled over I2C.
> > > > It provides both altmode and orientation handling.
> > > >
> > > > Add a driver with support for the following modes:
> > > >  - DP 4lanes
> > > >  - USB3
> > > >  - DP 2lanes + USB3
> > > >
> > > > Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> >
> > > > + retimer->supplies[0].supply = "vdd33";
> > > > + retimer->supplies[1].supply = "vdd18";
> > > > + retimer->supplies[2].supply = "vdd15";
> > >
> > > vdd115?
> > >
> > > > + retimer->supplies[3].supply = "vcc";
> >
> > I took a look at the schematics and it seems like all but one of the
> > above supply names are wrong and that some are missing. "vcc" also does
> > not exist in either the binding or dt patches you sent separately.
> >
> > From what I can tell the supplies are:
> >
> >       vdd             1.15 V
> >       vdd33           3.3 V
> >       vdd33_cap       3.3 V
> >       vddat           1.15 V
> >       vddar           1.15 V
> >       vddio           1.8 V
>
> The schematics seem to suggest that vdd, vddat and vddar are all
> supplied by the 1.15V supply. As for the vdd33 and vdd33_cap, their
> seem to be supplied by the 3.3V supply.

Please follow the datasheet when naming the supplies. Some of them
might be supplied by a single rail, but that might be a property of
your platform.

>
> >
> > Also, have you checked that there are no ordering constraints between
> > the supplies?
>
> The documentation seems to suggest that there are some timing as well as
> ordering contrains, yes. I can't tell for sure if that is really needed
> or not.

Again, please follow the datasheet.

>
> Thanks for reviewing.
>
> >
> > Johan
> >
>
> Abel



-- 
With best wishes
Dmitry