CONFIG_EFI_EARLYCON (not configurable)

modulename: earlycon.ko

configname: CONFIG_EFI_EARLYCON

Linux Kernel Configuration
└─>Device Drivers
└─>Firmware Drivers
└─>EFI_EARLYCON
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
source code:
drivers/firmware/efi/earlycon.c