genirq: Expand generic show_interrupts()

Some archs want to print extra information for certain irq_chips which
is per irq and not per chip. Allow them to provide a chip callback to
print the chip name and the extra information.

PowerPC wants to print the LEVEL/EDGE type information. Make it configurable.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 1d3577f..5d876c9 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -28,6 +28,7 @@
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>
 
+struct seq_file;
 struct irq_desc;
 struct irq_data;
 typedef	void (*irq_flow_handler_t)(unsigned int irq,
@@ -270,6 +271,7 @@
  * @irq_set_wake:	enable/disable power-management wake-on of an IRQ
  * @irq_bus_lock:	function to lock access to slow bus (i2c) chips
  * @irq_bus_sync_unlock:function to sync and unlock slow bus (i2c) chips
+ * @irq_print_chip:	optional to print special chip info in show_interrupts
  * @flags:		chip specific flags
  *
  * @release:		release function solely used by UML
@@ -317,6 +319,8 @@
 	void		(*irq_bus_lock)(struct irq_data *data);
 	void		(*irq_bus_sync_unlock)(struct irq_data *data);
 
+	void		(*irq_print_chip)(struct irq_data *data, struct seq_file *p);
+
 	unsigned long	flags;
 
 	/* Currently used only by UML, might disappear one day.*/