By default, the kernel recipe linux-imx-tq (based on FSLC kernel 5.4-1.0.0-imx) is built. An alternative kernel based on LSDK-20.12-V5.4-RT can be selected for PREEMPT_RT support by adding the following to local.conf or a custom DISTRO config:
PREFERRED_PROVIDER_virtual/kernel_tqmls1028a = "linux-rt-lsdk-tq"
Please note that the default linux-imx-tq kernel has received more thorough testing and it is therefore recommended for most usecases.
Differing from the LS1028A defaults, the TQMLS1028A device trees use an external sensor IC (connected to a measurement diode inside the SoC) instead of the builtin TMU as their primary data source for CPU core temperature. The external IC features a greater measurement range and higher precision.
The sensor is used for automatic core clock reduction and shutdown in the case of overheating.