#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/gpio.h>
#include <linux/kthread.h>
#include <linux/delay.h>

MODULE_LICENSE("GPL");

#define LED_ON 1
#define LED_OFF 0
#define DELAY_TIME 1000

static unsigned int gpioLED = 17;
static bool ledOn = 0;
static struct task_struct *task;

static int flash(void *arg){
    while(!kthread_should_stop()){
        set_current_state(TASK_RUNNING);
        ledOn = !ledOn;
        set_current_state(TASK_INTERRUPTIBLE);
        msleep(DELAY_TIME);
    }
    return 0;
}

static int __init gpio_blink_init(void){
    if (!gpio_is_valid(gpioLED)){
        printk(KERN_INFO "GPIO_TEST: invalid LED GPIO\n");
        return -ENODEV;
    }

    gpio_request(gpioLED, "stuff");
    gpio_direction_output(gpioLED, LED_OFF);
    gpio_export(gpioLED, false);

    task = kthread_run(flash, NULL, "LED_flash_thread");
    return 0;
}

static void __exit gpio_blink_exit(void){
    gpio_set_value(gpioLED, LED_OFF);
    gpio_unexport(gpioLED);
    gpio_free(gpioLED);
    kthread_stop(task);
}

module_init(gpio_blink_init);
module_exit(gpio_blink_exit);