ofnode: add {ofnode, dev}_read_resource_byname()

Linux supports platform_get_resource_byname() to look up a resource
by name.

We want a similar helper.  It is useful when a device node has named
register regions.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/core/ofnode.c

@@ -627,3 +627,15 @@ int ofnode_read_resource(ofnode node, uint index, struct resource *res)
 		return 0;
 	}
 }
+
+int ofnode_read_resource_byname(ofnode node, const char *name,
+				struct resource *res)
+{
+	int index;
+
+	index = ofnode_stringlist_search(node, "reg-names", name);
+	if (index < 0)
+		return index;
+
+	return ofnode_read_resource(node, index, res);
+}

drivers/core/read.c

@@ -164,3 +164,9 @@ int dev_read_resource(struct udevice *dev, uint index, struct resource *res)
 {
 	return ofnode_read_resource(dev_ofnode(dev), index, res);
 }
+
+int dev_read_resource_byname(struct udevice *dev, const char *name,
+			     struct resource *res)
+{
+	return ofnode_read_resource_byname(dev_ofnode(dev), name, res);
+}

include/dm/ofnode.h

@@ -625,5 +625,7 @@ int ofnode_read_simple_size_cells(ofnode node);
 bool ofnode_pre_reloc(ofnode node);
 
 int ofnode_read_resource(ofnode node, uint index, struct resource *res);
+int ofnode_read_resource_byname(ofnode node, const char *name,
+				struct resource *res);
 
 #endif

include/dm/read.h

@@ -359,13 +359,24 @@ int dev_read_enabled(struct udevice *dev);
 /**
  * dev_read_resource() - obtain an indexed resource from a device.
  *
- * @dev: devuce to examine
+ * @dev: device to examine
  * @index index of the resource to retrieve (0 = first)
  * @res returns the resource
  * @return 0 if ok, negative on error
  */
 int dev_read_resource(struct udevice *dev, uint index, struct resource *res);
 
+/**
+ * dev_read_resource_byname() - obtain a named resource from a device.
+ *
+ * @dev: device to examine
+ * @name: name of the resource to retrieve
+ * @res: returns the resource
+ * @return 0 if ok, negative on error
+ */
+int dev_read_resource_byname(struct udevice *dev, const char *name,
+			     struct resource *res);
+
 #else /* CONFIG_DM_DEV_READ_INLINE is enabled */
 
 static inline int dev_read_u32_default(struct udevice *dev,
@@ -513,6 +524,13 @@ static inline int dev_read_resource(struct udevice *dev, uint index,
 	return ofnode_read_resource(dev_ofnode(dev), index, res);
 }
 
+static inline int dev_read_resource_byname(struct udevice *dev,
+					   const char *name,
+					   struct resource *res)
+{
+	return ofnode_read_resource_byname(dev_ofnode(dev), name, res);
+}
+
 #endif /* CONFIG_DM_DEV_READ_INLINE */
 
 /**