ARM: Exynos: Add irq_domain and device tree support for combiner

Changes since v3:
- In dt case, the use of fixed gic linux irq number to map the combiner interrupt output is removed. This is replaced with the interrupt number obtained from the gic irq domain. (Thanks to Rob Herring and Grant Likely for this suggestion).
- Split the patch into two parts - irq_domain and device tree support addition.

Changes since v2:
- Rebased to Grant's irqdomain/next branch.

Changes since v1:
- Includes all changes suggested by Rob Herring.
- Tested with SPARSE_IRQ enabled.

This patchset adds irq_domain and device tree support for the Exynos Interrupt Combiner controller.

The first patch adds a common irq domain for the interrupts managed by the interrupt combiners. All the instances of irq combiner reference the common irq domain for translating hardware interrupts to linux irq number.

The second patch adds a interrupt specifier translator to support device tree based instantiation. It can translate interrupt specifiers for device nodes which use combiner as their interrupt parent.

This patchset is based on
http://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung.git [for-next]

with all irq_domain (v5) patches merged from
http://git.secretlab.ca/git/linux-2.6.git [irqdomain/next]

Thomas Abraham (2):
ARM: Exynos: Add irq_domain support for interrupt combiner
ARM: Exynos: Add device tree support for interrupt combiner

 .../bindings/arm/samsung/interrupt-combiner.txt    |   48 +++++++++
 arch/arm/mach-exynos/common.c                      |  112 ++++++++++++++++----
 2 files changed, 140 insertions(+), 20 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/samsung/interrupt-combiner.txt