Jeannie (Banana Pi+HomeGenie) is not meant to be used for GPIO programming and other advanced stuff.
It's meant to be a simple and ready to use solution.
You can connect supported home automation controllers (eg. Aeon Z-Stick II, CM15Pro, etc..) and also use the builtin IR receiver for controlling devices with an infrared remote.
If you want full support for GPIO and other more advanced stuff (and with r431 for Arduino programming as well) it is strongly suggested to use a Raspberry Pi.
Cheers,
g.