device property: Allow iterating over available child fwnodes

Implement a new helper function fwnode_get_next_available_child_node(),
which enables obtaining next enabled child fwnode, which
works on a similar basis to OF's of_get_next_available_child().

This commit also introduces a macro, thanks to which it is
possible to iterate over the available fwnodes, using the
new function described above.
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/base/property.c

@@ -997,6 +997,32 @@ fwnode_get_next_child_node(const struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL_GPL(fwnode_get_next_child_node);
 
+/**
+ * fwnode_get_next_available_child_node - Return the next
+ * available child node handle for a node
+ * @fwnode: Firmware node to find the next child node for.
+ * @child: Handle to one of the node's child nodes or a %NULL handle.
+ */
+struct fwnode_handle *
+fwnode_get_next_available_child_node(const struct fwnode_handle *fwnode,
+				     struct fwnode_handle *child)
+{
+	struct fwnode_handle *next_child = child;
+
+	if (!fwnode)
+		return NULL;
+
+	do {
+		next_child = fwnode_get_next_child_node(fwnode, next_child);
+
+		if (!next_child || fwnode_device_is_available(next_child))
+			break;
+	} while (next_child);
+
+	return next_child;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_next_available_child_node);
+
 /**
  * device_get_next_child_node - Return the next child node handle for a device
  * @dev: Device to find the next child node for.

include/linux/property.h

@@ -83,11 +83,17 @@ struct fwnode_handle *fwnode_get_next_parent(
 	struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_get_next_child_node(
 	const struct fwnode_handle *fwnode, struct fwnode_handle *child);
+struct fwnode_handle *fwnode_get_next_available_child_node(
+	const struct fwnode_handle *fwnode, struct fwnode_handle *child);
 
 #define fwnode_for_each_child_node(fwnode, child)			\
 	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
 	     child = fwnode_get_next_child_node(fwnode, child))
 
+#define fwnode_for_each_available_child_node(fwnode, child)		       \
+	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
+	     child = fwnode_get_next_available_child_node(fwnode, child))
+
 struct fwnode_handle *device_get_next_child_node(
 	struct device *dev, struct fwnode_handle *child);