genirq: Add the generic chip to the genirq docbook

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
diff --git a/Documentation/DocBook/genericirq.tmpl b/Documentation/DocBook/genericirq.tmpl
index b342234..d16d21b 100644
--- a/Documentation/DocBook/genericirq.tmpl
+++ b/Documentation/DocBook/genericirq.tmpl
@@ -464,6 +464,19 @@
 	protected via desc->lock, by the generic layer.
      </para>
   </chapter>
+
+  <chapter id="genericchip">
+     <title>Generic interrupt chip</title>
+     <para>
+       To avoid copies of identical implementations of irq chips the
+       core provides a configurable generic interrupt chip
+       implementation. Developers should check carefuly whether the
+       generic chip fits their needs before implementing the same
+       functionality slightly different themself.
+     </para>
+!Ekernel/irq/generic-chip.c
+  </chapter>
+
   <chapter id="structs">
      <title>Structures</title>
      <para>