[PATCH 0/3] GIC OF bindings

From: Mitch Bradley <redacted>
Date: Tue, 20 Sep 2011 18:58:12 -1000

interrupt-parent has been part of the interrupt mapping spec from the
inception of same.

http://www.openfirmware.info/docs/rec.intmap.d09.pdf

Thanks for the link.

In my vast collection of Sun OF dumps, I cannot find a single instance
where they've made use of this property, which is why I've never seen
it before.