Revert "of/irq: of_irq_find_parent: check for parent equal to child"

This reverts commit dc9372808412edbc653a675a526c2ee6c0c14a91.

As requested by Ben Herrenschmidt:
  "This breaks some powerpc platforms at least.  The practice of having
   a node provide an explicit "interrupt-parent" property pointing to
   itself is an old trick that we've used in the past to allow a
   device-node to have interrupts routed to different controllers.

   In that case, the node also contains an interrupt-map, so the node is
   its own parent, the interrupt resolution hits the map, which then can
   route each individual interrupt to a different parent."

Grant says:
  "Ah, nuts, yes that is broken then.  Yes, please revert the commit and
   Rob & I will come up with a better solution.

   Rob, I think it can be done by explicitly checking for np ==
   desc->interrupt_parent in of_irq_init() instead of relying on
   of_irq_find_parent() returning NULL."

Requested-by: Benjamin Herrenschmidt <>
Acked-by: Grant Likely <>
Cc: Rob Herring <>
Cc: linuxppc-dev <>
Cc: Tanmay Inamdar <>
Signed-off-by: Linus Torvalds <>
1 file changed