RE: [PATCH v5 01/14] dt-bindings: connector: add properties for typec

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Hi
> -----Original Message-----
> From: Oliver Neukum [mailto:oneukum@xxxxxxxx]
> Sent: 2018年5月3日 17:18
> To: Jun Li <jun.li@xxxxxxx>; robh+dt@xxxxxxxxxx;
> heikki.krogerus@xxxxxxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx;
> linux@xxxxxxxxxxxx
> Cc: gsomlo@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Peter Chen
> <peter.chen@xxxxxxx>; shufan_lee@xxxxxxxxxxx; a.hajda@xxxxxxxxxxx;
> cw00.choi@xxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> linux-usb@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 01/14] dt-bindings: connector: add properties for typec
> 
> Am Donnerstag, den 03.05.2018, 08:35 +0000 schrieb Jun Li:
> > Hi
> > > -----Original Message-----
> > > From: Oliver Neukum [mailto:oneukum@xxxxxxxx]
> > > Sent: 2018年5月3日 15:27
> > > To: Jun Li <jun.li@xxxxxxx>; robh+dt@xxxxxxxxxx;
> > > heikki.krogerus@xxxxxxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx;
> > > linux@xxxxxxxxxxxx
> > > Cc: gsomlo@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Peter Chen
> > > <peter.chen@xxxxxxx>; shufan_lee@xxxxxxxxxxx;
> a.hajda@xxxxxxxxxxx;
> > > cw00.choi@xxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > > linux-usb@xxxxxxxxxxxxxxx
> > > Subject: Re: [PATCH v5 01/14] dt-bindings: connector: add properties
> > > for typec
> > >
> > > Am Donnerstag, den 03.05.2018, 08:24 +0800 schrieb Li Jun:
> > > > +Optional properties for usb-c-connector:
> > > > +- power-role: should be one of "source", "sink" or "dual"(DRP) if
> > > > +typec
> > > > +  connector has power support.
> > > > +- try-power-role: preferred power role if "dual"(DRP) can support
> > > > +Try.SNK
> > > > +  or Try.SRC, should be "sink" for Try.SNK or "source" for Try.SRC.
> > > > +- data-role: should be one of "host", "device", "dual"(DRD) if
> > > > +typec
> > > > +  connector supports USB data.
> > >
> > > Hi,
> > >
> > > is this really correct?
> > >
> > > Can one implement a device that can operate as either DFP or UFP,
> > > but not implements the dynamic role switch that a DRP must support?
> >
> > You mean a port with DRD on data but not DRP on power?
> >
> > The data-role is newly added as the data role is not coupled with
> > power
> 
> No, I meant data role. As far as I can tell for a DRP you need to implement the
> detection logic described in chapter 4 of the spec.

Could you please point me the "detection logic" of typec spec chapter 4
you are referring to?

> I can see no reason why you couldn't build a port that can be switched between
> the data roles but not implement that logic.

I see there is dr_swap handling for data role swap in tcpm already, maybe
I misunderstood the "logic" you want here.

Regards
Li Jun
 
> 
> 	Regards
> 		Oliver

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