diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 52069d29ff12ef197c7d8a447ab27ffb7096d85e..94555951b6e13aa57be595c8a657c4a2ad25b93b 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -82,7 +82,7 @@ bool regmap_precious(struct regmap *map, unsigned int reg)
 }
 
 static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
-	unsigned int num)
+	size_t num)
 {
 	unsigned int i;