Hi > -----Original Message----- > From: Oliver Neukum [mailto:oneukum@xxxxxxxx] > Sent: 2018年5月8日 18:03 > 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 Freitag, den 04.05.2018, 08:59 +0000 schrieb Jun Li: > > > > > > > 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? > > Chapter 4.5.2.2, especially state diagramms 4.15 and 4.16 Figure 4-15 Connection State Diagram: DRP That's DRP case without try-power-role present, a simple DRP(Dual-Role-Power). Figure 4-16 Connection State Diagram: DRP with Accessory and Try.SRC Support That's DRP with try-power-role = "source" > > It just seems to me that a DRP and a physical port that can be switched > between UFP and DFP are not the same thing, but can be implemented. Yes, they are different, the former is DRP(Dual-Role-Power, power-role = "dual"), and the latter is DRD(Dual-Role-Data, data-role = "dual"). If a port can support both DRP and DRD, I think current tcpm already can support it. If a typec port only can sink power(power-role = "sink") but can support UFP and UFP switch on data (data-role = "dual"), in this case, we only can switch the data roles via dr_swap or sys, current tcpm may need more change to adapt the separation of power role and data role, but anyway all this can be implemented as you said. Thanks Li Jun > > Regards > Oliver ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
