How can I controll the GPIOs from the internal K20 IC on the Apalis TK1 module?

Hi all,

the Apalis TK1 module include an NXP K20 IC for expanding some GPIOs and Analog inputs (and USB and I2C). The K20 is connected to the Tegra K1 over SPI.
I want to know how I can defined and controll the GPIOs of the K20 over command line on LINUX?

I have try to use these as normal GPIOs like on your page: http://developer.toradex.com/knowledge-base/using-k20-companion-mcu-on-apalis-tk1#GPIO but this wasn’t working…(see my question: can't use K20 gpios on version v2.7b1 on TK1 - Toradex Community )

Maybe it’s possible to communicate over SPI commands? (if yes, I need an instruction with SPI commands for that)
Maybe the K20 needs an driver which must be loaded at first? (if yes, I need an instruction for loading the K20 driver on LINUX)

Thanks for your help and BR
Tobi

K20 support as well as host of other features provided by Apalis TK1 modules can only be used with downstream Linux4Tegra kernel and system image. Mainline image for TK1 is provided as is only and goes through very limited testing before release. It is intended as an example for customers who need mainline kernel and can live without few features. That being said, some K20 support will come to mainline image with Q1 2017 release.