Raspberry Pi cpufreq support

modulename: raspberrypi-cpufreq.ko

configname: CONFIG_ARM_RASPBERRYPI_CPUFREQ

Linux Kernel Configuration
└─>Power management and ACPI options
└─>CPU Frequency scaling
└─>Raspberry Pi cpufreq support
In linux kernel since version 5.1 (release Date: 2019-05-05)  
This adds the CPUFreq driver for Raspberry Pi

If in doubt, say N.

source code:
drivers/cpufreq/raspberrypi-cpufreq.c