Linux Input Driver question

My PC parallel port document at
http://www.epanorama.net/circuits/parallel_output.html
includes information how to directly access PC parallel
port hardware registers in many operating systems, including Linux.


Linux will allow acess to any port using the ioperm syscall.
Here is some code parts for Linux to write 255 to printer port:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <asm/io.h>

#define base 0x378           /* printer port base address */
#define value 255            /* numeric value to send to printer port */

main(int argc, char **argv)
{
   if (ioperm(base,1,1))
    fprintf(stderr, "Couldn't get the port at %x\n", base), exit(1);

   outb(value, base);
}

For reading use inb() function.