Waveshare 7inch HDMI LCD User Manual page 10

7inch HDMI LCD (B)
5. save and reboot your Pi
sudo reboot
After completing these steps. The LCD could rotate 90 degree both display and touch.
【Note】
90 degree: Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"
180 degree: Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"
270 degree: Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"