How to make Qt Program derive the signal from button on the board?

The 4 user keys on the AM335X SK are tied to GPIO0_30, GPIO2_3, GPIO2_2 and GPIO2_5. You have to poll the corresponding GPIOs to check if the keys are pressed.

So, I need to write a simple driver and my program can access them through this driver, Thus do i need to create 4 device file on the /dev??

Hi, any system call for GPIO i can use?? 

Thank you: ).

Hi:

            I use gpio_get_value() in my driver, there is no problem. But when i tried to call fwrite() in the user space to call corresponding function in my driver, first time everything is OK, and then I call fwrite again, my driver seems to not work(The function in my driver didn't print out anything on the console), i don't know what happened?