diff --git a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
index 18d3a4f69e63..fbd0fcdb42c8 100644
--- a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
+++ b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
@@ -31,7 +31,7 @@ struct uniphier_pinctrl_reg_region {
 	struct list_head node;
 	unsigned int base;
 	unsigned int nregs;
-	u32 vals[];
+	u32 vals[] __counted_by(nregs);
 };
 
 struct uniphier_pinctrl_priv {