Is there any practical documentation about using the Arduino headers on the i.MX6UL EVK as GPIOs with a linux kernel? Is there an app note or a sample device tree somewhere that demonstrates how to set up the Arduino headers so that they can be used for basic prototyping?
Specifically, I set out several days ago to configure GPIO1_01 as an input. According to the schematic, D14 is wired to I2C2_SDA, which is apparently connected to the LCD connector, the HDMI transmitter, the Audio Codec, and the Camera / SIM module as well. I thought I had it configured correctly in the device tree, but it isn't working and I don't even know if I should expect it to work as a GPIO at all the way it is routed on the board. Is there some kind of overview that covers what can be done with this EVK and the basics of how to do it?