Say Yes here if you have any input device that uses serial I/O to
communicate with the system. This includes the
* standard AT keyboard and PS/2 mouse *
as well as serial mice, Sun keyboards, some joysticks and 6dof
devices and more.

If unsure, say Y.

To compile this driver as a module, choose M here: the
module will be called serio.

source code:

drivers/input/serio/serio.c