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| author |   Johan Hovold <johan@kernel.org> | 2018-08-27 10:21:45 +0200 |
|---|---|---|
| committer |   Rob Herring <robh@kernel.org> | 2018-08-29 08:06:46 -0500 |
| commit | 36156f9241cb0f9e37d998052873ca7501ad4b36 (patch) | |
| tree | 203d1e52a9e5a942a2b99ae0ecb984fa87453df8 /drivers/of | |
| parent | Linux 4.19-rc1 (diff) | |
| download | linux-dev-36156f9241cb0f9e37d998052873ca7501ad4b36.tar.xz linux-dev-36156f9241cb0f9e37d998052873ca7501ad4b36.zip | |
of: add helper to lookup compatible child node
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: Johan Hovold <johan@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Diffstat (limited to 'drivers/of')
| -rw-r--r-- | drivers/of/base.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c index 466e3c8582f0..bc420d2aa5f5 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -720,6 +720,31 @@ 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 * @name: child name to look for. |