Connecting inout real to real data type

I have a tb_top in my top I have inout port. In the design I have real variable as input. I am trying to connect inout port to real but I am running into syntax error as real is not net. I tried making it tb_top port inout real but this is not supported. Can some one point how this can be rectified ?

module tb_top;
inout a;

module add
input real a;

Why does your tb_top have ports?

inout ports need multiple drivers to work correctly to get bidirectional behavior. Nets are the only kinds of signals that support resolution of multiple drivers. Built-in net types like wire can resolve the 4-state values 0,1,x, and z states along with strength. Any other datatype requires a user defined resolution function, and that is a more involved topic.

You need to have a better description of your situation before going down this path.