genirq: Improve documentation to match current implementation

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiri Kosina <trivial@kernel.org>
Link: http://lkml.kernel.org/r/1401178092-1228-3-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Documentation/IRQ-domain.txt

@@ -41,8 +41,7 @@ An interrupt controller driver creates and registers an irq_domain by
 calling one of the irq_domain_add_*() functions (each mapping method
 has a different allocator function, more on that later).  The function
 will return a pointer to the irq_domain on success.  The caller must
-provide the allocator function with an irq_domain_ops structure with
-the .map callback populated as a minimum.
+provide the allocator function with an irq_domain_ops structure.
 
 In most cases, the irq_domain will begin empty without any mappings
 between hwirq and IRQ numbers.  Mappings are added to the irq_domain

kernel/irq/internals.h

@@ -33,7 +33,7 @@ enum {
 };
 
 /*
- * Bit masks for desc->state
+ * Bit masks for desc->core_internal_state__do_not_mess_with_it
  *
  * IRQS_AUTODETECT		- autodetection in progress
  * IRQS_SPURIOUS_DISABLED	- was disabled due to spurious interrupt

kernel/irq/irqdomain.c

@@ -27,14 +27,14 @@ static struct irq_domain *irq_default_domain;
  * __irq_domain_add() - Allocate a new irq_domain data structure
  * @of_node: optional device-tree node of the interrupt controller
  * @size: Size of linear map; 0 for radix mapping only
+ * @hwirq_max: Maximum number of interrupts supported by controller
  * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no
  *              direct mapping
  * @ops: map/unmap domain callbacks
  * @host_data: Controller private data pointer
  *
- * Allocates and initialize and irq_domain structure.  Caller is expected to
- * register allocated irq_domain with irq_domain_register().  Returns pointer
- * to IRQ domain, or NULL on failure.
+ * Allocates and initialize and irq_domain structure.
+ * Returns pointer to IRQ domain, or NULL on failure.
  */
 struct irq_domain *__irq_domain_add(struct device_node *of_node, int size,
 				    irq_hw_number_t hwirq_max, int direct_max,