CONFIG_MFD_RK8XX (not configurable)

modulename: rk8xx-core.ko

configname: CONFIG_MFD_RK8XX

Linux Kernel Configuration
└─>Device Drivers
└─>Multifunction device drivers
└─>MFD_RK8XX
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
source code:
drivers/mfd//rk8xx-core.c
selects
CONFIG_MFD_CORE