IOPORT_F_IN
iop.flags = IOPORT_F_IN;
if (!(handler.flags & IOPORT_F_IN))
#define IOPORT_F_INOUT (IOPORT_F_IN | IOPORT_F_OUT)
INOUT_PORT(post, 0x84, IOPORT_F_IN, post_data_handler);