diff --git a/drivers/mfd/iqs62x.c b/drivers/mfd/iqs62x.c
index e03b4d38fbb0..1b465590567c 100644
--- a/drivers/mfd/iqs62x.c
+++ b/drivers/mfd/iqs62x.c
@@ -96,7 +96,7 @@ struct iqs62x_fw_blk {
 	u8 addr;
 	u8 mask;
 	u8 len;
-	u8 data[];
+	u8 data[] __counted_by(len);
 };
 
 struct iqs62x_info {