I actually requested a forum account to ask about touchscreen axis calibration for my setup, but have since figured it out, so might as well share results. I intend on using it in conjunction with OpenAutoPro running on a Pi4, and for my usecase it would be best if the ports were on the bottom. Note this is going in a convertible, so the 1100nits was super appealing in this application, and I plan on mounting it remotely, eg directly on top of the dash while the Pi lives with the audio amp under the dash.
Upon boot and initial setup following the info page (https://makerplane.org/?page_id=2792) , I actually found 90* rotation wasn't necessary, after Driver install everything was working normally in landscape orientation, however 'upside down' to the orientation I need.
So first step was trying the steps mentioned on the info page,
/boot/config.txt I set
display_rotate=2 #1：90；2: 180； 3: 270
for 180* rotation,
That worked. Next was touchscreen calibration.
adding the below to /etc/X11/xorg.conf.d/40-libinput.conf
180 degree: Option “CalibrationMatrix” “-1 0 1 0 -1 1 0 0 1”
Actually seemed to cause some sort of conflict with X, and the display would never start, resulting in being stuck on the splashscreen video looping.
I tried xinput_calibration, but that doesn't seem to account for inversion fo x/y as needed, eventually after tinkering found the following to work, hand typed:
Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"
Note the matrix is configured as such:
#[hscale] [vskew] [hoffset] [hskew] [vscale] [voffset] 0 0 1
#default:
# 1 0 0 0 1 0 0 0 1
So the config listed on the info page is correct, however the unicode characters are not standard double quotes and caused problems for Xserver. Be sure to hand type out the config if you run into trouble. Here's a screenshot of looking at the file in nano:
Hopefully this helps someone in the future avoid some head scratching