Register io

So I took a look at serial_io.v. I understand the idea now, you just
shift in the serial_addr first and then shift in the serial_data if you
want to write. Upon read, the highest bit of serial_addr should be set
to one. In usrp_inband_usb.v, inputs to serial_io.v is set to be inputs
of the higher level file. Is it ok for me to change those inputs to be
outputs of my own logic block? I am not sure if that will cause any
problem.

Leo