Richtek RT8973A EXTCON support

modulename: extcon-rt8973a.ko

configname: CONFIG_EXTCON_RT8973A

Linux Kernel Configuration
└─>Device Drivers
└─>External Connector Class (extcon) support
└─>Richtek RT8973A EXTCON support
In linux kernel since version 3.18 (release Date: 2014-12-07)  
If you say yes here you get support for the MUIC device of
Richtek RT8973A. The RT8973A is a USB port accessory detector
and switch that is optimized to protect low voltage system
from abnormal high input voltage (up to 28V).

source code:
selects
CONFIG_IRQ_DOMAIN
CONFIG_REGMAP_I2C
CONFIG_REGMAP_IRQ