enum irq_gc_flags — Initialization flags for generic irq chips
enum irq_gc_flags {
  IRQ_GC_INIT_MASK_CACHE,
  IRQ_GC_INIT_NESTED_LOCK,
  IRQ_GC_MASK_CACHE_PER_TYPE,
  IRQ_GC_NO_MASK,
  IRQ_GC_BE_IO
};  Initialize the mask_cache by reading mask reg
   Set the lock class of the irqs to nested for
   irq chips which need to call irq_set_wake on
   the parent irq. Usually GPIO implementations
      
Mask cache is chip type private
Do not calculate irq_data->mask
Use big-endian register accesses (default: LE)