Second USB3 port as OTG

[softsr]

Hello everyone!

According Wiki the USB3 Port on RockPro64 could be used as an OTG port.

I'm using Type C port for OTG device pretty succesfully, however there is a demand on having two OTG Ports simultaneously.

Till now I've managed to switch USB3 port into OTG mode with editing device tree over dtedit command where following string was set from "host" to "otg":

Code:

dr_mode = "otg";

Code:

usb1 {
        compatible = "rockchip,rk3399-dwc3";
        clocks = <0x8 0x82 0x8 0x84 0x8 0xf7 0x8 0xf9>;
        clock-names = "ref_clk", "suspend_clk", "bus_clk", "grf_clk";
        power-domains = <0x15 0x18>;
        resets = <0x8 0x126>;
        reset-names = "usb3-otg";
        #address-cells = <0x2>;
        #size-cells = <0x2>;
        ranges;
        status = "okay";
        phandle = <0xf1>;

        dwc3@fe900000 {
            compatible = "snps,dwc3";
            reg = <0x0 0xfe900000 0x0 0x100000>;
            interrupts = <0x0 0x6e 0x4 0x0>;
            dr_mode = "otg";
            phys = <0x2b 0x2c>;
            phy-names = "usb2-phy", "usb3-phy";
            phy_type = "utmi_wide";
            snps,dis_enblslpm_quirk;
            snps,dis-u2-freeclk-exists-quirk;
            snps,dis_u2_susphy_quirk;
            snps,dis-del-phy-power-chg-quirk;
            snps,tx-ipgap-linecheck-dis-quirk;
            snps,xhci-slow-suspend-quirk;
            snps,xhci-trb-ent-quirk;
            snps,usb3-warm-reset-on-resume-quirk;
            status = "okay";
            phandle = <0xf2>;
        };
    };

After that I can see the second device under /sys/class/udc:

Code:

rock64@rockpro64:~$ ls /sys/class/udc
fe800000.dwc3  fe900000.dwc3

However the second USB3 device (fe900000.dwc) doesn't work same as Type C port, no device appears there at all (I'm setting it as a mass storage).

So my question is:
is it generally a good idea to use two USB3 ports as OTG devices simultaneously?
If so, what could lack in setting it up?

[softsr]

I've loocked at the schematics of RockPro64 and found out, that the TYPEC1_U2VBUSDET (VBUS of USB3 PHY) seems not to be routed to the connector at all.

Could it be the reason for such behavior of USB3 in OTG mode?