/sys/class/tty/ttyS0/device/driver/serial8250/bus/devices/rt3xxx-ehci/subsystem/drivers/rt3xxx-ohci/rt3xxx-ohci/

../
bus/
driver/
modalias                4096
pools                   4096
subsystem/
uevent                  4096
usb1/
usb_host:usb_host1/