pinctrl-based I2C demultiplexer

modulename: i2c-demux-pinctrl.ko

configname: CONFIG_I2C_DEMUX_PINCTRL

Linux Kernel Configuration
└─>Device Drivers
└─>I2C support
└─>Multiplexer I2C Chip support
└─>Device Tree and Open Firmware support
└─>pinctrl-based I2C demultiplexer
In linux kernel since version 4.1 (release Date: 2015-06-21)  
If you say yes to this option, support will be included for an I2C
demultiplexer that uses the pinctrl subsystem. This is useful if you
want to change the I2C master at run-time depending on features.

source code: