The meaning of CONFIG_USB in U-Boot is different from that in Linux.
As you see in drivers/usb/Kconfig of Linux, CONFIG_USB enables the
USB host controller support, while CONFIG_USB_SUPPORT is used to
enable the whole of the USB sub-system.
When I added CONFIG_USB into Kconfig by commit 6e7e9294d321 ("usb:
add basic USB configs in Kconfig"), I planned to follow the Linux's
convention, i.e. CONFIG_USB to enable/disable the USB host support.
Then, commit 68f7c5db2d1e ("usb: Generic USB Kconfig option, that
fits both host and gadget and comments") changed the logic of the
CONFIG_USB to point to the whole of the USB sub-system. As a result,
currently we do not have an option for USB host.
This commit adds CONFIG_USB_HOST, which will be useful to compile
in the USB host support code.
CONFIG_USB_HOST is not referenced at all, but strangely some boards
define it in board headers. I removed them because USB_HOST will be
selected in Kconfig going forward.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2b58e1b76d