Hi Mark!
I’ve been trying to rotate the touch device as described in documentation:
xinput –set-prop ‘ADS7846 Touchscreen’ ‘Evdev Axis Inversion’ 0 0
But it doesn’t work anymore with recent kernels. As you can read here, there is a new method:
https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=172025
Following this instructions, this command works for me (rotate 180º):
xinput –set-prop ‘ADS7846 Touchscreen’ ‘Coordinate Transformation Matrix’ -1 0 1 0 -1 1 0 0 1
You can find a detailed description of this “Coordinate Transformation Matrix” here:
https://wiki.ubuntu.com/X/InputCoordinateTransformation
Please, update the documentation ASAP to avoid other users getting confused with this.
Thanks!