* Samsung Exynos Interrupt Combiner Controller

Samsung's Exynos4 architecture includes a interrupt combiner controller which
can combine interrupt sources as a group and provide a single interrupt request
for the group. The interrupt request from each group are connected to a parent
interrupt controller, such as GIC in case of Exynos4210.

The interrupt combiner controller consists of multiple combiners. Up to eight
interrupt sources can be connected to a combiner. The combiner outputs one
combined interrupt for its eight interrupt sources. The combined interrupt
is usually connected to a parent interrupt controller.

A single node in the device tree is used to describe the interrupt combiner
controller module (which includes multiple combiners). A combiner in the
interrupt controller module shares config/control registers with other
combiners. For example, a 32-bit interrupt enable/disable config register
can accommodate up to 4 interrupt combiners (with each combiner supporting
up to 8 interrupt sources).

Required properties:
- compatible: should be "samsung,exynos4210-combiner".
- interrupt-controller: Identifies the node as an interrupt controller.
- #interrupt-cells: should be <2>. The meaning of the cells are
	* First Cell: Combiner Group Number.
	* Second Cell: Interrupt number within the group.
- reg: Base address and size of interrupt combiner registers.
- interrupts: The list of interrupts generated by the combiners which are then
    connected to a parent interrupt controller. The format of the interrupt
    specifier depends in the interrupt parent controller.

Optional properties:
- samsung,combiner-nr: The number of interrupt combiners supported. If this
  property is not specified, the default number of combiners is assumed
  to be 16.
- interrupt-parent: pHandle of the parent interrupt controller, if not
  inherited from the parent node.


Example:

	The following is a an example from the Exynos4210 SoC dtsi file.

	combiner:interrupt-controller@10440000 {
		compatible = "samsung,exynos4210-combiner";
		interrupt-controller;
		#interrupt-cells = <2>;
		reg = <0x10440000 0x1000>;
		interrupts = <0 0 0>, <0 1 0>, <0 2 0>, <0 3 0>,
			     <0 4 0>, <0 5 0>, <0 6 0>, <0 7 0>,
			     <0 8 0>, <0 9 0>, <0 10 0>, <0 11 0>,
			     <0 12 0>, <0 13 0>, <0 14 0>, <0 15 0>;
	};