CONFIG_CRC4 (not configurable)

modulename: crc4.ko

configname: CONFIG_CRC4

Linux Kernel Configuration
└─>Library routines
└─>CRC4
In linux kernel since version 3.10 (release Date: 2013-06-30)  
The CRC4 library functions. Select this if your module uses any of
the functions from <linux/crc4.h>.

source code:
lib/crc4.c