title: Hello Word Device Tree Based device driver
body: <p>I have read and almost gone through all the linux kernel documentation on the device tree and device tree overlays.I am not able to understand if we have to create a new entree in the device tree of the platform or to create a new overlay for the device for a new driver based on device tree.
  I am looking for a simple led glowing driver example where led is connected to GPIO pin and its configuration is mentioned in the device tree overlay or device tree fragment on the board's platform.How can it be build/pushed and tested using the user space application.</p>