--- zzzz-none-000/linux-5.4.213/drivers/tty/serdev/core.c	2022-09-15 10:04:56.000000000 +0000
+++ alder-5690pro-762/linux-5.4.213/drivers/tty/serdev/core.c	2024-08-14 09:02:08.000000000 +0000
@@ -404,6 +404,17 @@
 }
 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 
+int serdev_device_ioctl(struct serdev_device *serdev,
+			unsigned int cmd, unsigned long arg)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->ioctl)
+		return -EOPNOTSUPP;
+	return ctrl->ops->ioctl(ctrl, cmd, arg);
+}
+EXPORT_SYMBOL_GPL(serdev_device_ioctl);
+
 static int serdev_drv_probe(struct device *dev)
 {
 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);