Discussion of basic interrupt configuration.

• include/
  • linux/
    • irq.h
    • irqchip.h
    • irqdesc.h
    • irqdomain.h
    • irqflags.h
    • irqhandler.h
    • irqnr.h
    • irqreturn.h
    • of_irq.h
    • irqchip/
• drivers/
  • irqchip/
  • of/
    • irq.c