Once you've enabled "USB support" and the proper "?HCI" USB host controller drivers, there are just a few more steps involved in getting USB up and running. You should enable the "Preliminary USB device filesystem," and then ensure that you enable any drivers specific to the actual USB peripherals that you will be using with Linux. For example, in order to enable support for my USB game controller, I enabled the "USB Human Interface Device (full HID) support". I also enabled "Input core support" and "Joystick support" under the main "Input core support" section.