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

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Message-ID: <ZvJpngJaav9Rb32k@linaro.org>
Date: Tue, 24 Sep 2024 10:26:22 +0300
From: Abel Vesa <abel.vesa@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...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 24-09-23 18:03:09, Dmitry Baryshkov wrote:
> 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.

Fair enough, then will use the ones Johan listed here as those are the
ones the datasheet lists as well.

> 
> >
> > >
> > > 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.

OK, will drop the bulk, will use simple get instead and add proper
timings according to datasheet.

> 
> >
> > Thanks for reviewing.
> >
> > >
> > > Johan
> > >
> >
> > Abel
> 
> 
> 
> -- 
> With best wishes
> Dmitry
> 

Thanks for feedback.

Abel