usb 2-0 configured as otg

[minicarpet]

Hi,
using our custom carrier board we use USB2 port 0 (same for flash operation) to connect a peripheral. For that I have few questions:

• if I understood well, OTG must be kept for flashing once the bootloader is flash through recovery mode and started ?
• I saw that NVIDIA provides this documentation, and it seems not clear when I read: "Remove the USB Port Endpoint." and then "Add the role-switch-default-mode property for USB Ports (optional)." -> anyway I've tester to keep it and adding role-switch-default-mode = "host"; but if I connect any devices, nothing is seen by the kernel. I also do not use VBUS sensing since I power up my device by myself.
• We didn't connect USB_VBUS_EN0 (pin 87) at all, do we need it to correctly switch as host ?
• which pin is the ID pin to switch to host mode ?
• can we have a bootloader device tree (to configure this usb as device) and one other for rootfs (to have the usb as host only) ?

Do someone already sucessfully reconfigured the usb2-0 to use it as host ?
I need it as device only for flashing, then it is always uses as host.

thank you

[jamesnguyen401]

Hello,

I am also using a custom carrier board, and think we have the same/similar issue. I've found that using the initrd-flash script that usb2-0 must be set to OTG in order for flashing to work.

When you set the role-switch-default-mode to host in your device tree, what shows up when you run the command
cat /sys/class/usb_role/usb2-0-role-switch/role ?

If you see the reply as host, then try the following command
echo host > /sys/class/usb_role/usb2-0-role-switch/role
And see if your USB port comes up

[minicarpet]

I got host but nothing appears.
I tried to use mode = "host" then using extlinux.conf and FDT settings to use this device tree from the kernel, and it works fine which prove that it is not an issue with data lines...

I think I need to configure id-pin and vbus-pin.

Best regards

[jamesnguyen401]

What is the vbus-supply set to in your device tree? Ours looks something like the following.

&xusb_padctl {
	ports {
		usb2-0 {
			mode = "otg";
			usb-role-switch;
			role-switch-default-mode = "host";
			vbus-supply = <&vdd_5v0_sys>;
		};
};

Apologies if thats not too helpful, i have not encountered issues with vbus

[minicarpet]

My device tree look like this:

padctl@3520000 {
  pads {
    usb2 {
	    lanes {
		    usb2-0 {
          status = "okay";
        };

        usb2-1 {
          status = "okay";
        };

        usb2-2 {
          status = "okay";
        };
	    };
    };
  };
   
  ports {
    usb2-0 {
      mode = "otg";
            usb-role-switch;
            role-switch-default-mode = "host";
      vbus-supply = <&vdd_5v0_sys>;
      status = "okay";
    };

    usb2-1 {
      mode = "host";
      vbus-supply = <&vdd_5v0_sys>;
      status = "okay";
    };

    usb2-2 {
      mode = "host";
      vbus-supply = <&vdd_5v0_sys>;
      status = "okay";
    };
  };

  usb@3550000 { /* XUDC / device controller */
    phys = <&{/bus@0/padctl@3520000/pads/usb2/lanes/usb2-0}>;
    phy-names = "usb2-0";
    status = "okay";
  };
  
  usb@3610000 {
    phys = <&{/bus@0/padctl@3520000/pads/usb2/lanes/usb2-0}>,
			     <&{/bus@0/padctl@3520000/pads/usb2/lanes/usb2-1}>,
			     <&{/bus@0/padctl@3520000/pads/usb2/lanes/usb2-2}>;
    phy-names = "usb2-0", "usb2-1", "usb2-2";
    status = "okay";
  };
};

and this does not work... I am not sure were I am wrong then since it looks similar as yours...
Our electronics is simple as well:

Note that we tried to put VBUS_EN0 to GND but it changes nothing.

How do you configure this pin 87 from the pinmux ? with usb function or as a gpio ?
Do I need nvidia,function = "xusb"; ?

[jamesnguyen401]

This is the section of VBUS from our pinmux. Pin 87 is left as a no-connect / rsvd1

usb_vbus_en0_pz1 {
nvidia,pins = "usb_vbus_en0_pz1";
nvidia,function = "rsvd1";
nvidia,pull = <TEGRA_PIN_PULL_DOWN>;
nvidia,tristate = <TEGRA_PIN_ENABLE>;
nvidia,enable-input = <TEGRA_PIN_DISABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};

usb_vbus_en1_pz2 {
nvidia,pins = "usb_vbus_en1_pz2";
nvidia,function = "rsvd1";
nvidia,pull = <TEGRA_PIN_PULL_DOWN>;
nvidia,tristate = <TEGRA_PIN_ENABLE>;
nvidia,enable-input = <TEGRA_PIN_DISABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};