default or selected kernelversion does not have config value CONFIG_ADMFM2000.
Result is shown for kernelversion 6.9.2

Analog Devices ADMFM2000 Dual Microwave Down Converter

modulename: admfm2000.ko

configname: CONFIG_ADMFM2000

Linux Kernel Configuration
└─>Device Drivers
└─>Industrial I/O support
└─>Frequency Synthesizers DDS/PLL
└─>Phase-Locked Loop (PLL) frequency synthesizers
└─>GPIO Support
└─>Analog Devices ADMFM2000 Dual Microwave Down Converter
In linux kernel since version 6.1.89 (release Date: 2024-04-29)  
Say yes here to build support for Analog Devices ADMFM2000 Dual
Microwave Down Converter.

To compile this driver as a module, choose M here: the
module will be called admfm2000.

source code: