Enable software triggers support

modulename: industrialio-sw-trigger.ko

configname: CONFIG_IIO_SW_TRIGGER

Linux Kernel Configuration
└─>Device Drivers
└─>Industrial I/O support
└─>Enable software triggers support
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Provides IIO core support for software triggers. A software
trigger can be created via configfs or directly by a driver
using the API provided.

source code:
drivers/iio/industrialio-sw-trigger.c

depends
CONFIG_IIO