USB OTG not working as HOST

Hi,
We have designed a custom carrier board for the jetson TX2 module.
we had a issue with the USB OTG not working as host.
after some research we got our problem solved by referring to this site
https://elinux.org/Jetson/TX2_USB#USB-Lane_Mapping
so we followed the steps given in the site and the OTG worked properly.

so my doubts are,

  1. what do you mean by GPIO regulators ?
  2. what changes do I need to do in my custom carrier board H/W design so that I don’t need to change the device tree.

in your TX2 adaptation guide(page 10), you have told to include vdd_usb2_5v supply to enable vbus-2-supply but I was not able to find the netnames anywhere in your schematics or any other document. so can you pls tell me what changes do I need to do in H/W so that we don’t need this device tree change

Regards,
R.Rohith yadav

Hi, the pin P00 of U29 is a enable pin for M.2 Key E in P2597 and that is needed to enable USB2_DP/DM on M.2 Key E. So is the name given usb2_5v.

Hi Trumany,
In our design we have used USB0 signals for the USB OTG,
but the below change makes it work,

  • vbus-2-supply = <&vdd_usb2_5v>;
  • vbus-2-supply = <&battery_reg>;
    but this is for the USB2 signals, then why does it affect the USB0 singals.

Thanks,
R.Rohith yadav

Sw tries to configure the vbus-2 supply and it fails since the expander is not available.
So, to avoid sw to fail, vbus-2 is supplied with battery supply which is a fixed regulator with no constraints. SW happily enables this dummy regulator and proceed.

1 Like

Hi Trumany,
I have some question regarding this,

  1. Why does changing the Vbus-2-supply (which is the enable for USB2 signals) affect the working of USB0 signals
  2. I don’t have the expander on my custom carrier board, so can I change something H/W wise in my board. so that the USB0 work on my custom carrier board without any device tree change.

Thanks,
R.Rohith yadav

  1. Comment #4 already answered the question.
  2. Changing device tree is easier and safer than hw change as no such hw changes verified before.