CONFIG_ETRAX_RS485_ON_PA_BIT 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_BIT.
Result is shown for kernelversion 6.7-rc3

RS-485 mode on PA bit

configname: CONFIG_ETRAX_RS485_ON_PA_BIT

Linux Kernel Configuration
└─>RS-485 mode on PA bit
In linux kernel since version 2.6.12  
Control Driver Output Enable on RS485 transceiver using a this bit
on PA port.