# # USB Gadget support on a system involves # (a) a peripheral controller, and # (b) the gadget driver using it. # # NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !! # # - Host systems (like PCs) need CONFIG_USB (with "A" jacks). # - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks). # - Some systems have both kinds of controllers. # # With help from a special transceiver and a "Mini-AB" jack, systems with # both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG). # menuconfig USB_GADGET bool "USB Gadget Support" help USB is a master/slave protocol, organized with one master host (such as a PC) controlling up to 127 peripheral devices. The USB hardware is asymmetric, which makes it easier to set up: you can't connect a "to-the-host" connector to a peripheral. U-Boot can run in the host, or in the peripheral. In both cases you need a low level bus controller driver, and some software talking to it. Peripheral controllers are often discrete silicon, or are integrated with the CPU in a microcontroller. The more familiar host side controllers have names like "EHCI", "OHCI", or "UHCI", and are usually integrated into southbridges on PC motherboards. Enable this configuration option if you want to run U-Boot inside a USB peripheral device. Configure one hardware driver for your peripheral/device side bus controller, and a "gadget driver" for your peripheral protocol.