Use OTG Guru to get a list of the USB devices connected to the OTG port.
For each device the app will display:
- path
- VID PID
- Class
- Interfaces
The app will list all the available interfaces.
For each interface the app will list all the available endpoints and their details.

I hope that you will find the OTG Guru useful if you are developing USB devices or drivers.

If you are a developer you might also like our RoboRemo app useful for debugging embedded stuff:
https://play.google.com/store/apps/details?id=com.hardcodedjoy.roboremo&referrer=utm_source%3Dogd