of/irq: Add interrupts-names property to name an irq resource

Add a interrupts-names property to allow the possibility to provide a name
to any interrupts entries.  If the name is available, use it to name the
resource, otherwise keep the device full name.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
[grant.likely: use "interrupt-names" and tidy documentation]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 0f0cfa3..9cf0060 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -341,9 +341,18 @@
 	/* Only dereference the resource if both the
 	 * resource and the irq are valid. */
 	if (r && irq) {
+		const char *name = NULL;
+
+		/*
+		 * Get optional "interrupts-names" property to add a name
+		 * to the resource.
+		 */
+		of_property_read_string_index(dev, "interrupt-names", index,
+					      &name);
+
 		r->start = r->end = irq;
 		r->flags = IORESOURCE_IRQ;
-		r->name = dev->full_name;
+		r->name = name ? name : dev->full_name;
 	}
 
 	return irq;