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Diffstat (limited to 'arch/powerpc/platforms/pseries/of_helpers.c')
-rw-r--r--arch/powerpc/platforms/pseries/of_helpers.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
new file mode 100644
index 000000000000..2798933c0e38
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -0,0 +1,38 @@
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+
+#include "of_helpers.h"
+
+/**
+ * pseries_of_derive_parent - basically like dirname(1)
+ * @path: the full_name of a node to be added to the tree
+ *
+ * Returns the node which should be the parent of the node
+ * described by path. E.g., for path = "/foo/bar", returns
+ * the node with full_name = "/foo".
+ */
+struct device_node *pseries_of_derive_parent(const char *path)
+{
+ struct device_node *parent;
+ char *parent_path = "/";
+ const char *tail;
+
+ /* We do not want the trailing '/' character */
+ tail = kbasename(path) - 1;
+
+ /* reject if path is "/" */
+ if (!strcmp(path, "/"))
+ return ERR_PTR(-EINVAL);
+
+ if (tail > path) {
+ parent_path = kstrndup(path, tail - path, GFP_KERNEL);
+ if (!parent_path)
+ return ERR_PTR(-ENOMEM);
+ }
+ parent = of_find_node_by_path(parent_path);
+ if (strcmp(parent_path, "/"))
+ kfree(parent_path);
+ return parent ? parent : ERR_PTR(-EINVAL);
+}