How to configure and enable the barebox state?

[Trostel Alain]

Hi,

I would like to configure and enable the barebox state. My assumption is
that I need to change the following device tree for my Phytec AM335x
SOM:

arch/arm/dts/am335x-phytec-phycore-som.dts

But from the documentation
(http://www.barebox.org/doc/latest/devicetree/bindings/barebox/barebox,state.html) it is not clear to me where exactly I need to add the variable node example. Furthermore, I have check that the 'CONFIG_OFDEVICE' is enabled.
So, where is the correct place to add the variable node configuration
and what needs to be enabled in barebox?

Best regards,
Alain