SPI multiplexer support

modulename: spi-mux.ko
configname: CONFIG_SPI_MUX

Linux Kernel Configuration
└─> Device Drivers
└─> SPI support
└─> SPI multiplexer support

In linux kernel since version 5.1 (release Date: 2019-05-05)  

This adds support for SPI multiplexers. Each SPI mux will be
accessible as a SPI controller, the devices behind the mux will appear
to be chip selects on this controller. It is still necessary to
select one or more specific mux-controller drivers.

source code: