- atusb-common.c (atusb_open): claim interface, so that we can do bulk
I/O without complaints from the kernel
- atusb-common.h (atusb_interrupt_wait), atusb-common.c: blocking read
for interrupt status byte on EP1
- atusb.c (atusb_driver), atusb-spi.c (atusb_spi_driver): provide the
interrupt_wait operation