of/address: Add new API of_iomap_by_name and of_get_address_by_name

Create new API of_iomap_by_name and of_get_address_by_name, which
would read "reg-names" property and get the reg address by its
name.

Change-Id: I7ce30da5a7cbc29f8349641af97ac7ed16b4f506
Signed-off-by: Xiaocheng Li <lix@codeaurora.org>
[imaund@codeaurora.org: Resolved trivial context conflicts.]
Signed-off-by: Ian Maund <imaund@codeaurora.org>

drivers/of/address.c

@@ -788,6 +788,22 @@ unsigned long __weak pci_address_to_pio(phys_addr_t address)
 #endif
 }
 
+const __be32 *of_get_address_by_name(struct device_node *dev, const char *name,
+		u64 *size, unsigned int *flags)
+{
+	int index;
+	if (!name)
+		return NULL;
+
+	/* Try to read "reg-names" property and get the index by name */
+	index = of_property_match_string(dev, "reg-names", name);
+	if (index < 0)
+		return NULL;
+
+	return of_get_address(dev, index, size, flags);
+}
+EXPORT_SYMBOL(of_get_address_by_name);
+
 static int __of_address_to_resource(struct device_node *dev,
 		const __be32 *addrp, u64 size, unsigned int flags,
 		const char *name, struct resource *r)
@@ -1026,3 +1042,19 @@ bool of_dma_is_coherent(struct device_node *np)
 	return false;
 }
 EXPORT_SYMBOL_GPL(of_dma_is_coherent);
+
+void __iomem *of_iomap_by_name(struct device_node *np, const char *name)
+{
+	int index;
+
+	if (!name)
+		return NULL;
+
+	/* Try to read "reg-names" property and get the index by name */
+	index = of_property_match_string(np, "reg-names", name);
+	if (index < 0)
+		return NULL;
+
+	return of_iomap(np, index);
+}
+EXPORT_SYMBOL(of_iomap_by_name);

include/linux/of_address.h

@@ -36,6 +36,8 @@ extern struct device_node *of_find_matching_node_by_address(
 					const struct of_device_id *matches,
 					u64 base_address);
 extern void __iomem *of_iomap(struct device_node *device, int index);
+extern void __iomem *of_iomap_by_name(struct device_node *device,
+					const char *name);
 
 /* Extract an address from a device, returns the region size and
  * the address space flags too. The PCI version uses a BAR number
@@ -43,6 +45,8 @@ extern void __iomem *of_iomap(struct device_node *device, int index);
  */
 extern const __be32 *of_get_address(struct device_node *dev, int index,
 			   u64 *size, unsigned int *flags);
+extern const __be32 *of_get_address_by_name(struct device_node *dev,
+			   const char *name, u64 *size, unsigned int *flags);
 
 extern int pci_register_io_range(phys_addr_t addr, resource_size_t size);
 extern unsigned long pci_address_to_pio(phys_addr_t addr);