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 

 

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

thank you