Ember.js - Reference parent view's controller variable in partial

I have a template home.hbs that renders a partial {{partial "my_partial"}}

Now, in my_partial, a reference to this gives me <app@controller:home::ember442>

But what I really need to do is grab a variable defined in HomeController inside the partial with something like: {{this.variable_name}} where variable_name is defined in HomeController as:

variableName: function(){
  return some_value;
}.property('variableName')

Is there a way to do this in Ember? Let me know if you need clarification