of/address: Add reg-names property to name an iomem resource

Add a reg-names property to allow for reg regions to be reference by name
instead of by index.  Some devices have multiple register regions which
are more naturally referenced by name.

If the name is available, use it to name the resource when creating a devices.
Otherwise keep the device name.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
[Generalized documentation to be for any -names property]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 72c33fb..66d96f1 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -14,7 +14,7 @@
 static struct of_bus *of_match_bus(struct device_node *np);
 static int __of_address_to_resource(struct device_node *dev,
 		const __be32 *addrp, u64 size, unsigned int flags,
-				    struct resource *r);
+		const char *name, struct resource *r);
 
 /* Debug utility */
 #ifdef DEBUG
@@ -215,7 +215,7 @@
 	addrp = of_get_pci_address(dev, bar, &size, &flags);
 	if (addrp == NULL)
 		return -EINVAL;
-	return __of_address_to_resource(dev, addrp, size, flags, r);
+	return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
 }
 EXPORT_SYMBOL_GPL(of_pci_address_to_resource);
 #endif /* CONFIG_PCI */
@@ -529,7 +529,7 @@
 
 static int __of_address_to_resource(struct device_node *dev,
 		const __be32 *addrp, u64 size, unsigned int flags,
-				    struct resource *r)
+		const char *name, struct resource *r)
 {
 	u64 taddr;
 
@@ -551,7 +551,8 @@
 		r->end = taddr + size - 1;
 	}
 	r->flags = flags;
-	r->name = dev->full_name;
+	r->name = name ? name : dev->full_name;
+
 	return 0;
 }
 
@@ -569,11 +570,16 @@
 	const __be32	*addrp;
 	u64		size;
 	unsigned int	flags;
+	const char	*name = NULL;
 
 	addrp = of_get_address(dev, index, &size, &flags);
 	if (addrp == NULL)
 		return -EINVAL;
-	return __of_address_to_resource(dev, addrp, size, flags, r);
+
+	/* Get optional "reg-names" property to add a name to a resource */
+	of_property_read_string_index(dev, "reg-names",	index, &name);
+
+	return __of_address_to_resource(dev, addrp, size, flags, name, r);
 }
 EXPORT_SYMBOL_GPL(of_address_to_resource);