CONFIG_HAS_TXX9_SERIAL (not configurable)

configname: CONFIG_HAS_TXX9_SERIAL

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>HAS_TXX9_SERIAL
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  

is selected by
CONFIG_SERIAL_TXX9