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

[Jun Li <jun.li@nxp.com>]

Hi
> -----Original Message-----
> From: Oliver Neukum [mailto:oneukum@suse.com]
> Sent: 2018年5月3日 15:27
> To: Jun Li <jun.li@nxp.com>; robh+dt@kernel.org;
> heikki.krogerus@linux.intel.com; gregkh@linuxfoundation.org;
> linux@roeck-us.net
> Cc: gsomlo@gmail.com; dl-linux-imx <linux-imx@nxp.com>; Peter Chen
> <peter.chen@nxp.com>; shufan_lee@richtek.com; a.hajda@samsung.com;
> cw00.choi@samsung.com; devicetree@vger.kernel.org;
> linux-usb@vger.kernel.org
> 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
role in new PD spec, in practice, I think this is very normal, Heikki already
added a patch to separate the power and data role in class driver, but tcpm
hasn't changed accordingly for this yet, so current tcpm may not allow your
question case, but from property definition point view, we should not limit
this and let the 2 roles independent each other.

Thanks
Jun
> 
> 	Regards
> 		Oliver