HOW TO GET INPUT FROM GPIO?

[fenil.patel]

Hi,

    I want to get input from gpio from an external button. i try many syntaxes for getting input from gpio but nothing is work. 

i try 

nrf_gpio_pin_dir_get(12)

nrf_gpio_pin_sense_get(12)

nrf_gpio_pin_read(12)

i not get any output from it.