The long explanation is here
Before:
# dmesg
......
[ 9.606887] thermal_sys: Failed to find 'trips' node
[ 9.606902] thermal_sys: Failed to find trip points for thermal-sensor id=1
[ 9.606923] sun8i-thermal 1c24c00.thermal-sensor: Failed to register sensor 1 (-EINVAL)
[ 9.606938] sun8i-thermal: probe of 1c24c00.thermal-sensor failed with error -22
......
My patch for sun8i-r40.dtsi. Yes, it's copy-paste with changing names of a cpu thermal trip point for a gpu thermal trip point.
Now it's ok
# ls /sys/devices/virtual/thermal/
cooling_device0 thermal_zone0 thermal_zone1
fix_gpu_thermal_zone_sun8i-r40_bananapi-m2u.patch