On Tue 2019-03-26 14:41:01, Sakari Ailus wrote: > 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. > > Also reorder fwnode_get_parent() in property.c according to the same order > as in property.h. > > diff --git a/drivers/base/property.c b/drivers/base/property.c > index 8b91ab380d14..61eb6ceacc3f 100644 > --- a/drivers/base/property.c > +++ b/drivers/base/property.c > @@ -554,17 +567,49 @@ struct fwnode_handle *fwnode_get_next_parent(struct fwnode_handle *fwnode) > EXPORT_SYMBOL_GPL(fwnode_get_next_parent); > > /** > - * fwnode_get_parent - Return parent firwmare node > - * @fwnode: Firmware whose parent is retrieved > + * fwnode_count_parents - Return the number of parents a node has > + * @fwnode: The node the parents of which are to be counted > * > - * Return parent firmware node of the given node if possible or %NULL if no > - * parent was available. > + * Returns the number of parents a node has. > */ > -struct fwnode_handle *fwnode_get_parent(const struct fwnode_handle *fwnode) > +unsigned int fwnode_count_parents(struct fwnode_handle *fwnode) > { > - return fwnode_call_ptr_op(fwnode, get_parent); > + unsigned int count; > + > + fwnode_handle_get(fwnode); > + > + for (count = 0; fwnode; count++) > + fwnode = fwnode_get_next_parent(fwnode); Is it guaranteed that all parents stay when fwnode_get_next_parent() releases the reference count for each counted member? > + > + return count - 1; We could start counting from count = -1; > } > -EXPORT_SYMBOL_GPL(fwnode_get_parent); > +EXPORT_SYMBOL_GPL(fwnode_count_parents); > + Best Regards, Petr