[PATCH v8 10/10] arm64: dts: rockchip: rk3399-evb-ind: Add support for DisplayPort

[Peter Chen]

On Thu, Oct 30, 2025 at 11:14 AM Chaoyi Chen <chaoyi.chen at rock-chips.com> wrote:
>
> On 10/30/2025 10:50 AM, Peter Chen wrote:
>
> >>> Okay.  My question is basic: USB2 PHY supplies DP/DM, and the DP/DM is
> >>> short for Type-C connector,
> >>> and no control is needed for Type-C application.
> >>> Why is there a remote-endpoint connection between USB2 PHY and Type-C connector?
> >>   From the perspective of Type-C, this should not be added.  Is the approach in v2 correct [0] ?
> >>
> > Have you tried debugging based on upstream code?
>
> Yes, I have tried both the v2 and v8 approaches, and both can work.
>
>
> > v2 is correct, but the dts needs to improve.
> > - There is a remote-endpoint connection for USB role switch between
> > Type-C connector
> > device and USB controller device
> > - There is a remote-endpoint connection for orientation and lane configuration
> > between Type-C connector device and USB/DP PHY device.
>
> In v8 patch5, we implemented typec_mux and typec_switch in the USB/DP PHY.
>
> I think the current remote-endpoint connections are all child node of the USB/DP PHY. That is:
>
>
> &tcphy0_dp {
>      mode-switch;
>      ...
> };
>
>
> &tcphy0_usb3 {
>      orientation-switch;
>      ...
> };
>
>
> Does this still need to be improved? Thank you.
>

Hi Chaoyi,

There are two questions I have still not seen the answer to:
- Why USB2 PHY is related to your Type-C patch?
- How does the USB role switch event notify the USB controller driver, eg dwc3?

Peter
>
> >
> > Peter
> >
> >> [0]: https://lore.kernel.org/all/20250715112456.101-6-kernel@airkyi.com/
> >>
> >> Or is the following approach correct?
> >>
> >>
> >> port at 0 {
> >>       reg = <0>;
> >>
> >>       usbc_hs: endpoint {
> >>           remote-endpoint = <&tcphy0>;
> >>       };
> >> };
> >>
> >> port at 1 {
> >>       reg = <1>;
> >>
> >>       usbc_ss: endpoint {
> >>           remote-endpoint = <&tcphy0>;
> >>       };
> >> };
> >>
> >> port at 2 {
> >>       reg = <2>;
> >>
> >>       usbc_dp: endpoint {
> >>           remote-endpoint = <&tcphy0_typec_dp>;
> >>       };
> >> };
> >>
> >>
> >>>>>>> +                               port at 1 {
> >>>>>>> +                                       reg = <1>;
> >>>>>>> +
> >>>>>>> +                                       usbc_ss: endpoint {
> >>>>>>> + remote-endpoint = <&tcphy0_typec_ss>;
> >>>>>>> +                                       };
> >>>>>>> +                               };
> >>>>>>> +
> >>>>>>> +                               port at 2 {
> >>>>>>> +                                       reg = <2>;
> >>>>>>> +
> >>>>>>> +                                       usbc_dp: endpoint {
> >>>>>>> + remote-endpoint = <&tcphy0_typec_dp>;
> >>>>>>> +                                       };
> >>>>>>> +                               };
> >>>>>>> +                       };
> >>>>>>> +               };
> >>>>>>> +       };
> >>>>>>> +};
> >>>>>>> +
> >>>>>> .....
> >>>>>>>     &u2phy0 {
> >>>>>>>            status = "okay";
> >>>>>>> +
> >>>>>>> +       port {
> >>>>>>> +               u2phy0_typec_hs: endpoint {
> >>>>>>> +                       remote-endpoint = <&usbc_hs>;
> >>>>>>> +               };
> >>>>>>> +       };
> >>>>>>>     };
> >>>>>>>
> >>>>>> There is no switch and mux, how to co-work with Type-C?
> >>>>> I checked the phy-rockchip-inno-usb2.c but did not find any switch or mux. Does this mean that we need to implement them? Thank you.
> >>>> Wait a minute, actually we have multiple hardware interfaces, one of which is Type-C, eventually connected to USBDPPHY, and the other is micro-usb connected to U2PHY.
> >>> I assume the Micro-USB connector does not use Type-C/PD IC, is it
> >>> right? Does it relate to this patch?
> >>>
> >>> Best regards,
> >>> Peter
> >>>
> >
> --
> Best,
> Chaoyi
>