default or selected kernelversion does not have config value CONFIG_DGAP.
Result is shown for kernelversion 6.5.1

Digi EPCA PCI products

modulename: dgap.ko

configname: CONFIG_DGAP

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Digi EPCA PCI products
In linux kernel since version 3.12 (release Date: 2013-11-03)  
Driver for the Digi International EPCA PCI based product line

source code: