[PATCH v2 13/22] OF: base: import parent/child functions from Linux OF API

[Sebastian Hesselbarth]

This imports of_get_parent, of_get_next_available_child, and
of_get_child_by_name and corresponding helpers from Linux OF API.
of_get_next_child is not imported but implemented as list iterator
instead. Also, of_get_child_count and of_get_available_child_count
are introduced.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth at gmail.com>
---
Cc: barebox at lists.infradead.org

Changelog:
v1->v2:
- make of_get_parent return node->parent also for root_node
  (Suggested by Sascha Hauer)
- use list iterator instead of of_get_next_child
  (Suggested by Sascha Hauer)
- move of_get_child_count to base.c to avoid compile warnings
- introduce of_get_available_child_count
---
 drivers/of/base.c |   97 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/of.h      |   41 ++++++++++++++++++++++
 2 files changed, 138 insertions(+), 0 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 39eddb2..ee0496d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -875,6 +875,103 @@ int of_device_is_available(const struct device_node *device)
 }
 EXPORT_SYMBOL(of_device_is_available);
 
+/**
+ *	of_get_parent - Get a node's parent if any
+ *	@node:	Node to get parent
+ *
+ *	Returns a pointer to the parent node or NULL if already at root.
+ */
+struct device_node *of_get_parent(const struct device_node *node)
+{
+	return (!node) ? NULL : node->parent;
+}
+EXPORT_SYMBOL(of_get_parent);
+
+/**
+ *	of_get_next_available_child - Find the next available child node
+ *	@node:	parent node
+ *	@prev:	previous child of the parent node, or NULL to get first
+ *
+ *      This function is like of_get_next_child(), except that it
+ *      automatically skips any disabled nodes (i.e. status = "disabled").
+ */
+struct device_node *of_get_next_available_child(const struct device_node *node,
+	struct device_node *prev)
+{
+	for_each_child_of_node(node, prev)
+		if (of_device_is_available(prev))
+			return prev;
+	return NULL;
+}
+EXPORT_SYMBOL(of_get_next_available_child);
+
+/**
+ *	of_get_child_count - Count child nodes of given parent node
+ *	@parent:	parent node
+ *
+ *      Returns the number of child nodes or -EINVAL on NULL parent node.
+ */
+int of_get_child_count(const struct device_node *parent)
+{
+	struct device_node *child;
+	int num = 0;
+
+	if (!parent)
+		return -EINVAL;
+
+	for_each_child_of_node(parent, child)
+		num++;
+
+	return num;
+}
+EXPORT_SYMBOL(of_get_child_count);
+
+/**
+ *	of_get_available_child_count - Count available child nodes of given
+ *      parent node
+ *	@parent:	parent node
+ *
+ *      Returns the number of available child nodes or -EINVAL on NULL parent
+ *      node.
+ */
+int of_get_available_child_count(const struct device_node *parent)
+{
+	struct device_node *child;
+	int num = 0;
+
+	if (!parent)
+		return -EINVAL;
+
+	for_each_child_of_node(parent, child)
+		if (of_device_is_available(child))
+			num++;
+
+	return num;
+}
+EXPORT_SYMBOL(of_get_available_child_count);
+
+/**
+ *	of_get_child_by_name - Find the child node by name for a given parent
+ *	@node:	parent node
+ *	@name:	child name to look for.
+ *
+ *      This function looks for child node for given matching name
+ *
+ *	Returns a node pointer if found or NULL.
+ */
+struct device_node *of_get_child_by_name(const struct device_node *node,
+				const char *name)
+{
+	struct device_node *child;
+
+	for_each_child_of_node(node, child)
+		if (child->name && (of_node_cmp(child->name, name) == 0))
+			return child;
+
+	return NULL;
+}
+EXPORT_SYMBOL(of_get_child_by_name);
+
 void of_print_nodes(struct device_node *node, int indent)
 {
 	struct device_node *n;
diff --git a/include/of.h b/include/of.h
index f508435..917466f 100644
--- a/include/of.h
+++ b/include/of.h
@@ -197,6 +197,14 @@ extern struct device_node *of_find_node_with_property(
 	struct device_node *from, const char *prop_name);
 extern int of_device_is_available(const struct device_node *device);
 
+extern struct device_node *of_get_parent(const struct device_node *node);
+extern struct device_node *of_get_next_available_child(
+	const struct device_node *node, struct device_node *prev);
+extern int of_get_child_count(const struct device_node *parent);
+extern int of_get_available_child_count(const struct device_node *parent);
+extern struct device_node *of_get_child_by_name(const struct device_node *node,
+					const char *name);
+
 extern void of_alias_scan(void);
 extern int of_alias_get_id(struct device_node *np, const char *stem);
 extern const char *of_alias_get(struct device_node *np);
@@ -241,6 +249,33 @@ static inline struct device_node *of_get_root_node(void)
 	return NULL;
 }
 
+static inline struct device_node *of_get_parent(const struct device_node *node)
+{
+	return NULL;
+}
+
+static inline struct device_node *of_get_next_available_child(
+		const struct device_node *node, struct device_node *prev)
+{
+	return NULL;
+}
+
+static inline int of_get_child_count(const struct device_node *parent)
+{
+	return -ENOSYS;
+}
+
+static inline int of_get_available_child_count(const struct device_node *parent)
+{
+	return -ENOSYS;
+}
+
+static inline struct device_node *of_get_child_by_name(
+			const struct device_node *node, const char *name)
+{
+	return NULL;
+}
+
 static inline struct property *of_find_property(const struct device_node *np,
 						const char *name,
 						int *lenp)
@@ -329,4 +364,10 @@ static inline struct device_node *of_find_matching_node(
 	for (dn = of_find_node_with_property(NULL, prop_name); dn; \
 	     dn = of_find_node_with_property(dn, prop_name))
 
+#define for_each_child_of_node(parent, child) \
+	list_for_each_entry(child, &parent->children, parent_list)
+#define for_each_available_child_of_node(parent, child) \
+	for (child = of_get_next_available_child(parent, NULL); child != NULL; \
+	     child = of_get_next_available_child(parent, child))
+
 #endif /* __OF_H */
-- 
1.7.2.5