arch/powerpc/platforms/pseries/of_helpers.c

   1 #include <linux/string.h>
   2 #include <linux/err.h>
   3 #include <linux/slab.h>
   4 #include <linux/of.h>
   5
   6 #include "of_helpers.h"
   7
   8 /**
   9  * pseries_of_derive_parent - basically like dirname(1)
  10  * @path:  the full_name of a node to be added to the tree
  11  *
  12  * Returns the node which should be the parent of the node
  13  * described by path.  E.g., for path = "/foo/bar", returns
  14  * the node with full_name = "/foo".
  15  */
  16 struct device_node *pseries_of_derive_parent(const char *path)
  17 {
  18         struct device_node *parent;
  19         char *parent_path = "/";
  20         const char *tail;
  21
  22         /* We do not want the trailing '/' character */
  23         tail = kbasename(path) - 1;
  24
  25         /* reject if path is "/" */
  26         if (!strcmp(path, "/"))
  27                 return ERR_PTR(-EINVAL);
  28
  29         if (tail > path) {
  30                 parent_path = kstrndup(path, tail - path, GFP_KERNEL);
  31                 if (!parent_path)
  32                         return ERR_PTR(-ENOMEM);
  33         }
  34         parent = of_find_node_by_path(parent_path);
  35         if (strcmp(parent_path, "/"))
  36                 kfree(parent_path);
  37         return parent ? parent : ERR_PTR(-EINVAL);
  38 }