How can fast read GPIO status at TX1 r28.2?

How can fast read GPIO status at TX1 r28.2?

Don’t know if this will give you what you want, but this is a similar topic:
https://devtalk.nvidia.com/default/topic/995395/jetson-tk1/fast-access-to-gpio/

The kernel versions differ, so I’m not sure if it is 100% applicable, but I do know at least parts of it are exact matches to use on R28.2.