example: gpio_request

example:

int ret = 0; 
ret = gpio_request(S5PV210_GPJ1(4), "turn_on_gpio_xxx");
if (ret<0)
    printk(KERN_INFO "nice: gpio_request error-turn_on_gpio_xxx");
else 
{
    gpio_direction_output(S5PV210_GPJ1(4), 1);    //set the gpio is output and the value is 1
    gpio_export(S5PV210_GPJ1(4), true);    //let user can modify the gpio value
}

if the value of S5PV210_GPJ1(4) is 98
cat /sys/class/gpio/gpio98/value