Where is Driver in NetBsd code base

SW-NetBSD/usr/src/sys/arch/evbppc/moduleName/componentKernelDrivers.c

i.e. i2c.c asicA.c fpgaB.c

• contain open/close/ioctl calls and HW init function.
• This level calls real low driver.
• This level does not implements semaphore.
• Device address/offset or register address passed thru via caddr_t structure. Format user definable?