Kontron KTAM3874-pITX - Manual (Page 85)

KTD-S0057-I Page 81 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
int read_bkl_val (int *val)
{
int
fd;
char str[8];
fd = open (dev_act, O_RDONLY);
if (fd < 0)
return -1;
if (read (fd, str, sizeof (str)) < 0)
{
close (fd);
return -1;
}
str [3] = '\0'; /* Maximal value is 255 */
*val = atoi (str);
close (fd);
return 0;
}
int write_bkl_power (int pow_state)
{
int
fd;
char str[8];
if ((pow_state < 0) || (pow_state > MAX_BKL_POW))
return -1;
fd = open (dev_pow, O_WRONLY);
if (fd < 0)
return -1;
sprintf (str, "%d", pow_state);
if (write (fd, str, strlen (str)) != strlen (str))
{
close (fd);
return -1;
}
close (fd);
return 0;
}
int main (void)
{
int
value;
printf ("\nBacklight test program\n");
if (! read_bkl_val (&value))
printf ("Actual backlight value: %d\n", value);
else
printf ("Backlight read function fails !\n");