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

[Chaoyi Chen]

Hi Peter,

On 10/30/2025 9:34 AM, Peter Chen wrote:
> On Wed, Oct 29, 2025 at 6:32 PM Chaoyi Chen <chaoyi.chen@xxxxxxxxxxxxxx> wrote:
> > On 10/29/2025 6:21 PM, Chaoyi Chen wrote:
> >
> > > Hi Peter,
> > >
> > > On 10/29/2025 5:45 PM, Peter Chen wrote:
> > > > > +&i2c4 {
> > > > > +       i2c-scl-rising-time-ns = <475>;
> > > > > +       i2c-scl-falling-time-ns = <26>;
> > > > > +       status = "okay";
> > > > > +
> > > > > +       usbc0: typec-portc@22 {
> > > > > +               compatible = "fcs,fusb302";
> > > > > +               reg = <0x22>;
> > > > > +               interrupt-parent = <&gpio1>;
> > > > > +               interrupts = <RK_PA2 IRQ_TYPE_LEVEL_LOW>;
> > > > > +               pinctrl-names = "default";
> > > > > +               pinctrl-0 = <&usbc0_int>;
> > > > > +               vbus-supply = <&vbus_typec>;
> > > > > +
> > > > > +               usb_con: connector {
> > > > > +                       compatible = "usb-c-connector";
> > > > > +                       label = "USB-C";
> > > > > +                       data-role = "dual";
> > > > > +                       power-role = "dual";
> > > > > +                       try-power-role = "sink";
> > > > > +                       op-sink-microwatt = <1000000>;
> > > > > +                       sink-pdos =
> > > > > +                               <PDO_FIXED(5000, 2500, PDO_FIXED_USB_COMM)>;
> > > > > +                       source-pdos =
> > > > > +                               <PDO_FIXED(5000, 1500, PDO_FIXED_USB_COMM)>;
> > > > > +
> > > > > +                       altmodes {
> > > > > +                               displayport {
> > > > > +                                       svid = /bits/ 16 <0xff01>;
> > > > > +                                       vdo = <0x00001c46>;
> > > > > +                               };
> > > > > +                       };
> > > > > +
> > > > > +                       ports {
> > > > > +                               #address-cells = <1>;
> > > > > +                               #size-cells = <0>;
> > > > > +
> > > > > +                               port@0 {
> > > > > +                                       reg = <0>;
> > > > > +
> > > > > +                                       usbc_hs: endpoint {
> > > > > + remote-endpoint = <&u2phy0_typec_hs>;
> > > > > +                                       };
> > > > > +                               };
> > > > > +
> > > > Why USB2 PHY needs to be notified for Type-C connection?
> > > I think the USB-connector binding require a port@0 for High Speed.  So I filled in USB2 PHY here. And I have looked up boards with the same usage, and some of the results are as follows:
> > >
> > > - rk3399-firefly.dts
> > >
> > > - rk3399-pinebook-pro.dts
> > >
> > > - rk3399-eaidk-610.dts
> 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] ?

[0]: https://lore.kernel.org/all/20250715112456.101-6-kernel@xxxxxxxxxx/

Or is the following approach correct?


port@0 {
    reg = <0>;

    usbc_hs: endpoint {
        remote-endpoint = <&tcphy0>;
    };
};

port@1 {
    reg = <1>;

    usbc_ss: endpoint {
        remote-endpoint = <&tcphy0>;
    };
};

port@2 {
    reg = <2>;

    usbc_dp: endpoint {
        remote-endpoint = <&tcphy0_typec_dp>;
    };
};


> > > > > +                               port@1 {
> > > > > +                                       reg = <1>;
> > > > > +
> > > > > +                                       usbc_ss: endpoint {
> > > > > + remote-endpoint = <&tcphy0_typec_ss>;
> > > > > +                                       };
> > > > > +                               };
> > > > > +
> > > > > +                               port@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