How to get the outter parent controller from inside an ember component?

Currently I'm passing a custom keyword into the component like so (as I loop over each model in my array controller)

{{#each thing in controller}}
  {{my-thing foo=controller}}
{{/each}}

Then inside my component I can add a custom attributeBindings and bind to "foo" but I'd like to think I can get access to the parent controller (from inside the component itself)

How else can I get this from inside the component in ember 1.8+ ?