CONFIG_ETRAX_RS485_ON_PA is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_ETRAX_RS485_ON_PA.
Result is shown for kernelversion 6.7-rc3

RS-485 mode on PA

configname: CONFIG_ETRAX_RS485_ON_PA

Linux Kernel Configuration
└─>RS-485 mode on PA
In linux kernel since version 2.6.12  
Control Driver Output Enable on RS485 transceiver using a pin on PA
port:
Axis 2400/2401 uses PA 3.