Hello All
I m new to driver development.I want to write my own parallel port driver.If a call is made to existing parallel port driver(parport) it should not be called.Instead it should call my own driver..

My question is hw to write a driver,and hw to disable the existing driver...i tried to remove the existing modules(parport,parport_pc,lp0) using rmmod command...I googled and got some codes and tested,but of no use..
This is my code
int parlelport_init(void)
{
int result;

port = check_region(0x378, 1);
if (port)
{
printk("<1>parlelport: cannot reserve 0x378\n");
result = port;
}
request_region(0x378, 1, "parlelport");

/* Registering device */
result = register_chrdev(parlelport_major, "parlelport",&parlelport_fops);
if (result < 0)
{
printk("<1>parlelport: cannot obtain major number %d\n", parlelport_major);
return result;
}
return 0;

}

this is the code for read
parlelport_buffer = inb(0x378);

copy_to_user(buf,&parlelport_buffer,1);
/* We change the reading position as best suits */
if (*f_pos == 0)
{
*f_pos+=1;
return 1;
}
else
{
return 0;
}

this is the code for write

char *tmp;
/* Buffer writing to the device */
char parlelport_buffer;
tmp=buf+count-1;
copy_from_user(&parlelport_buffer,tmp,1);
printk("\n Inside Write\n");
printk(parlelport_buffer);
/* Writing to the port */
outb(parlelport_buffer,0x378);

return 1;


can anyone suggest me any ideas to make it work?


Thanks in advance

hi friend.

i think u are referring the example from linuxjournal.com

i faced a similar problem.

The solution i came up with is i removed the whole parport folder

from /lib/modules/kernel/drivers .

rebooted

and the original modules no more registered 0x378!!! hurray


then i used the custom made parallelport module for led lighting.