looks like there is a kernel driver for the spi based touchpads, but would still require you to get the unit attached to your spi bus
https://patchwork.kernel.org/project/linux-input/patch/20190204081947.25152-3-ronald@innovation.ch/
[quote|format=featured][code]
The keyboard and trackpad on recent MacBook's (since 8,1) and
MacBookPro's (13,* and 14,*) are attached to an SPI controller instead
of USB, as previously. The higher level protocol is not publicly
documented and hence has been reverse engineered. As a consequence there
are still a number of unknown fields and commands. However, the known
parts have been working well and received extensive testing and use.
[/code][/quote]