On Tue, May 29, 2018 at 4:10 PM, Ricardo Ribalda Delgado
[off-list ref] wrote:

Standard TTY port that can be loaded/unloaded via serdev sysfs. This
serdev driver can only be used by serdev controllers that are compatible
with ttyport.

+config SERIAL_DEV_CTRL_TTYDEV
+       tristate "TTY port dynamically loaded by the Serial Device Bus"
+       help
+         Say Y here if you want to create a bridge driver between the Serial
+         device bus and the TTY chardevice. This driver can be dynamically
+         loaded/unloaded by the Serial Device Bus.
+
+         If unsure, say Y.
+       depends on SERIAL_DEV_CTRL_TTYPORT

+       default m

Hmm... Can't we survive w/o this by default?

+static int __init ttydev_serdev_init(void)
+{
+       return serdev_device_driver_register(&ttydev_serdev_driver);
+}
+module_init(ttydev_serdev_init);
+
+static void __exit ttydev_serdev_exit(void)
+{
+       return serdev_device_driver_unregister(&ttydev_serdev_driver);
+}
+module_exit(ttydev_serdev_exit);

Isn't above is just a macro in serdev.h?
I.e. module_serdev_device_driver().

-- 
With Best Regards,
Andy Shevchenko