linux/Documentation/ABI/testing/configfs-usb-gadget-serial

What:		/config/usb-gadget/gadget/functions/gser.name
Date:		Jun 2013
KernelVersion:	3.11
Description:

		This item contains just one readonly attribute: port_num.
		It contains the port number of the /dev/ttyGS<n> device
		associated with gser function's instance "name".