1 files changed, 33 insertions, 2 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 2f25d2dfecfa..1d667eb730e1 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1286,6 +1286,13 @@ int of_phandle_iterator_init(struct of_phandle_iterator *it,
 
 	memset(it, 0, sizeof(*it));
 
+	/*
+	 * one of cell_count or cells_name must be provided to determine the
+	 * argument length.
+	 */
+	if (cell_count < 0 && !cells_name)
+		return -EINVAL;
+
 	list = of_get_property(np, list_name, &size);
 	if (!list)
 		return -ENOENT;
@@ -1512,10 +1519,17 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
 				const char *cells_name, int index,
 				struct of_phandle_args *out_args)
 {
+	int cell_count = -1;
+
 	if (index < 0)
 		return -EINVAL;
-	return __of_parse_phandle_with_args(np, list_name, cells_name, -1,
-					    index, out_args);
+
+	/* If cells_name is NULL we assume a cell count of 0 */
+	if (!cells_name)
+		cell_count = 0;
+
+	return __of_parse_phandle_with_args(np, list_name, cells_name,
+					    cell_count, index, out_args);
 }
 EXPORT_SYMBOL(of_parse_phandle_with_args);
 
@@ -1765,6 +1779,23 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na
 	struct of_phandle_iterator it;
 	int rc, cur_index = 0;
 
+	/*
+	 * If cells_name is NULL we assume a cell count of 0. This makes
+	 * counting the phandles trivial as each 32bit word in the list is a
+	 * phandle and no arguments are to consider. So we don't iterate through
+	 * the list but just use the length to determine the phandle count.
+	 */
+	if (!cells_name) {
+		const __be32 *list;
+		int size;
+
+		list = of_get_property(np, list_name, &size);
+		if (!list)
+			return -ENOENT;
+
+		return size / sizeof(*list);
+	}
+
 	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
 	if (rc)
 		return rc;