/sys/bus/usb/devices/usb1/usb_device%3Ausbdev1.1/device/driver/usb2/2-0%3A1.0/ep_81/subsystem/

../
usbdev1.1_ep00/
usbdev1.1_ep81/
usbdev2.1_ep00/
usbdev2.1_ep81/