diff --git a/drivers/pinctrl/pinconf.c b/drivers/pinctrl/pinconf.c
index d16ef8797f59..8da2d6db228c 100644
--- a/drivers/pinctrl/pinconf.c
+++ b/drivers/pinctrl/pinconf.c
@@ -512,7 +512,7 @@ static int pinconf_dbg_config_write(struct file *file,
 	int i;
 
 	/* Get userspace string and assure termination */
-	buf_size = min(count, (sizeof(buf)-1));
+	buf_size = min(count, (size_t)(sizeof(buf)-1));
 	if (copy_from_user(buf, user_buf, buf_size))
 		return -EFAULT;
 	buf[buf_size] = 0;