int platform_read_button(int index);
platform_read_button reads the platform button with index index, returning 1 when the button is pressed and 0 when released.
platform_read_button takes care of initializing the GPIO pin and handing buttons connected with both positive and negative logic. If the button's GPIO cannot be claimed, the button is not and 0
platform_read_button returns 1 when the button is pressed and 0 when the button is released.
A button doesn't need to be directly attached to a GPIO, but this is the typical configuration.