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authorSakari Ailus <sakari.ailus@linux.intel.com>2019-10-03 15:32:11 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-10-11 11:26:55 +0200
commit87e5e95db31a27d117fbb4a5d464f44adb4c2ee2 (patch)
tree8169cd9ea74f307d7b31d10fddefccafed9ce813 /drivers/base/property.c
parenta57b7fb783eb352d91b0bf8391682b30bacae667 (diff)
device property: Add functions for accessing node's parents
Add two convenience functions for accessing node's parents: fwnode_count_parents() returns the number of parent nodes a given node has. fwnode_get_nth_parent() returns node's parent at a given distance from the node itself. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base/property.c')
-rw-r--r--drivers/base/property.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/drivers/base/property.c b/drivers/base/property.c
index 3d9dffbe9637..f2e555e68b56 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -591,6 +591,52 @@ struct fwnode_handle *fwnode_get_next_parent(struct fwnode_handle *fwnode)
EXPORT_SYMBOL_GPL(fwnode_get_next_parent);
/**
+ * fwnode_count_parents - Return the number of parents a node has
+ * @fwnode: The node the parents of which are to be counted
+ *
+ * Returns the number of parents a node has.
+ */
+unsigned int fwnode_count_parents(const struct fwnode_handle *fwnode)
+{
+ struct fwnode_handle *__fwnode;
+ unsigned int count;
+
+ __fwnode = fwnode_get_parent(fwnode);
+
+ for (count = 0; __fwnode; count++)
+ __fwnode = fwnode_get_next_parent(__fwnode);
+
+ return count;
+}
+EXPORT_SYMBOL_GPL(fwnode_count_parents);
+
+/**
+ * fwnode_get_nth_parent - Return an nth parent of a node
+ * @fwnode: The node the parent of which is requested
+ * @depth: Distance of the parent from the node
+ *
+ * Returns the nth parent of a node. If there is no parent at the requested
+ * @depth, %NULL is returned. If @depth is 0, the functionality is equivalent to
+ * fwnode_handle_get(). For @depth == 1, it is fwnode_get_parent() and so on.
+ *
+ * The caller is responsible for calling fwnode_handle_put() for the returned
+ * node.
+ */
+struct fwnode_handle *fwnode_get_nth_parent(struct fwnode_handle *fwnode,
+ unsigned int depth)
+{
+ unsigned int i;
+
+ fwnode_handle_get(fwnode);
+
+ for (i = 0; i < depth && fwnode; i++)
+ fwnode = fwnode_get_next_parent(fwnode);
+
+ return fwnode;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_nth_parent);
+
+/**
* fwnode_get_next_child_node - Return the next child node handle for a node
* @fwnode: Firmware node to find the next child node for.
* @child: Handle to one of the node's child nodes or a %NULL handle.