device property: Add fwnode_handle_get()

fwnode_handle_get() is used to obtain a reference to a fwnode_handle
container. In this case this is OF specific struct device_node.

This complements fwnode_handle_put() which is already implemented.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/property.c

@@ -1040,6 +1040,17 @@ struct fwnode_handle *device_get_named_child_node(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(device_get_named_child_node);
 
+/**
+ * fwnode_handle_get - Obtain a reference to a device node
+ * @fwnode: Pointer to the device node to obtain the reference to.
+ */
+void fwnode_handle_get(struct fwnode_handle *fwnode)
+{
+	if (is_of_node(fwnode))
+		of_node_get(to_of_node(fwnode));
+}
+EXPORT_SYMBOL_GPL(fwnode_handle_get);
+
 /**
  * fwnode_handle_put - Drop reference to a device node
  * @fwnode: Pointer to the device node to drop the reference to.

include/linux/property.h

@@ -90,6 +90,7 @@ struct fwnode_handle *fwnode_get_named_child_node(struct fwnode_handle *fwnode,
 struct fwnode_handle *device_get_named_child_node(struct device *dev,
 						  const char *childname);
 
+void fwnode_handle_get(struct fwnode_handle *fwnode);
 void fwnode_handle_put(struct fwnode_handle *fwnode);
 
 unsigned int device_get_child_node_count(struct device *dev);