Kontron KTAM3874-pITX - Manual (Page 71)

KTD-S0057-I Page 67 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
else
{
if (write (fd_tmp, EDGE_FALL, sizeof(EDGE_FALL)-1) != sizeof(EDGE_FALL)-1)
{
close (fd_tmp);
return -1;
}
}
close (fd_tmp);
return 0;
}
int main (void)
{
int i, ret, value;
struct pollfd poll_fd;
printf ("\nGPIO IRQ test program\n");
if ((! gpio_export (GP2_17)) && (! gpio_set_direction (GP2_17, GPIO_IN)))
{
if ((! gpio_set_edge (GP2_17, IRQ_RISE)) && (! gpio_open_read (GP2_17)))
{
poll_fd.fd = fd [GP2_17];
poll_fd.events = POLLPRI;
poll_fd.revents = 0;
printf ("Waiting for interrupt ...\n");
/* Read before Poll is necessary */
gpio_read (GP2_17, &value);
ret = poll (&poll_fd, 1, POLL_TIMEOUT);
switch (ret)
{
case -1: printf ("Interrupt routine fails !\n"); break;
case 0: printf ("Timeout has occured !\n"); break;
case 1: if (poll_fd.revents & POLLPRI)
printf ("IRQ successfully detected.\n");
else
printf ("Unexpected problem !\n");
break;
default : printf ("Unexpected problem !\n"); break;
}
gpio_close_read (GP2_17);
}
else
{
printf ("\nCannot set edge or open GPIO !\n");
gpio_unexport (GP2_17);
return -1;
}
gpio_unexport (GP2_17);
}