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>

Documentation/devicetree/bindings/resource-names.txt

+Some properties contain an ordered list of 1 or more datum which are
+normally accessed by index.  However, some devices will have multiple
+values which are more naturally accessed by name.  Device nodes can
+include a supplemental property for assigning names to each of the list
+items.  The names property consists of a list of strings in the same
+order as the data in the resource property.
+
+The following supplemental names properties are defined.
+
+Resource Property	Supplemental Names Property
+-----------------	---------------------------
+reg			reg-names
+clocks			clock-names
+interrupts		interrupt-names
+
+Usage:
+
+The -names property must be used in conjunction with the normal resource
+property. If not it will be ignored.
+
+Examples:
+
+l4-abe {
+	compatible = "simple-bus";
+	#address-cells = <2>;
+	#size-cells = <1>;
+	ranges = <0 0 0x48000000 0x00001000>, /* MPU path */
+		 <1 0 0x49000000 0x00001000>; /* L3 path */
+	mcasp {
+		compatible = "ti,mcasp";
+		reg = <0 0x10 0x10>, <0 0x20 0x10>,
+		      <1 0x10 0x10>, <1 0x20 0x10>;
+		reg-names = "mpu", "dat",
+			    "dma", "dma_dat";
+	};
+
+	timer {
+		compatible = "ti,timer";
+		reg = <0 0x40 0x10>, <1 0x40 0x10>;
+		reg-names = "mpu", "dma";
+	};
+};
+
+
+usb {
+	compatible = "ti,usb-host";
+	reg = <0x4a064000 0x800>, <0x4a064800 0x200>,
+	      <0x4a064c00 0x200>;
+	reg-names = "config", "ohci", "ehci";
+};

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 @@ int of_pci_address_to_resource(struct device_node *dev, int bar,
 	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 @@ EXPORT_SYMBOL(of_get_address);
 
 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 @@ static int __of_address_to_resource(struct device_node *dev,
 		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 @@ int of_address_to_resource(struct device_node *dev, int index,
 	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);