problem with GPIO pin as input with nrf9160 using zephyr RTOS

Hi,

I'm using GPIO pin as input button  with nrf9160 using Zephyr RTOS, but when I was press the button I didn't get any response from button state.

hear is my code 

#include <zephyr/zephyr.h>
#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/sys/util.h>
#include <zephyr/sys/printk.h>
#include <inttypes.h>

#define SLEEP_TIME_MS	1000

#define button 6

void main(void)
{
	int ret;
	int count=0;
	
	 int gpio_dev =device_get_binding("GPIO_0");
       if(!gpio_dev)
       {
        printk("Cannot bind gpio device\n");
        return 0;
       }
	ret = gpio_pin_configure(gpio_dev,button, GPIO_INPUT);

	printk("Press the button\n");
	
		while (1)
		{
			int val = gpio_pin_get(gpio_dev,button);
			
			if (val!= 0)
			{
			count=0;
			}
			
			count++;
			printk("count =%d\n",count);
			k_msleep(SLEEP_TIME_MS);
		}

}

when I press button count  value not changing, if anyone know where I did wrong please help me to solve this.

thank you