From 87e5e95db31a27d117fbb4a5d464f44adb4c2ee2 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Thu, 3 Oct 2019 15:32:11 +0300 Subject: 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 Reviewed-by: Andy Shevchenko Signed-off-by: Rafael J. Wysocki --- drivers/base/property.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'drivers') 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 @@ -590,6 +590,52 @@ 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. -- cgit v1.2.3-70-g09d2