Commit f3e3c50c authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman

of: add helper to lookup compatible child node

[ Upstream commit 36156f9241cb0f9e37d998052873ca7501ad4b36 ]

Add of_get_compatible_child() helper that can be used to lookup
compatible child nodes.

Several drivers currently use of_find_compatible_node() to lookup child
nodes while failing to notice that the of_find_ functions search the
entire tree depth-first (from a given start node) and therefore can
match unrelated nodes. The fact that these functions also drop a
reference to the node they start searching from (e.g. the parent node)
is typically also overlooked, something which can lead to use-after-free
bugs.
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 42c0c719
......@@ -712,6 +712,31 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
}
EXPORT_SYMBOL(of_get_next_available_child);
/**
* of_get_compatible_child - Find compatible child node
* @parent: parent node
* @compatible: compatible string
*
* Lookup child node whose compatible property contains the given compatible
* string.
*
* Returns a node pointer with refcount incremented, use of_node_put() on it
* when done; or NULL if not found.
*/
struct device_node *of_get_compatible_child(const struct device_node *parent,
const char *compatible)
{
struct device_node *child;
for_each_child_of_node(parent, child) {
if (of_device_is_compatible(child, compatible))
break;
}
return child;
}
EXPORT_SYMBOL(of_get_compatible_child);
/**
* of_get_child_by_name - Find the child node by name for a given parent
* @node: parent node
......
......@@ -265,6 +265,8 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
extern struct device_node *of_get_next_available_child(
const struct device_node *node, struct device_node *prev);
extern struct device_node *of_get_compatible_child(const struct device_node *parent,
const char *compatible);
extern struct device_node *of_get_child_by_name(const struct device_node *node,
const char *name);
......@@ -462,6 +464,12 @@ static inline bool of_have_populated_dt(void)
return false;
}
static inline struct device_node *of_get_compatible_child(const struct device_node *parent,
const char *compatible)
{
return NULL;
}
static inline struct device_node *of_get_child_by_name(
const struct device_node *node,
const char *name)
......
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