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SoC Thermal Temperature

Reading the SoC Temperature

The i.MX 6UL/6ULL/6ULZ SoC has an internal temperature sensor that can be read. The temperature is reported in millidegrees Celsius:

cat /sys/class/thermal/thermal_zone0/temp

43000

Thermal Setpoints

The Linux kernel will throttle the CPU and GPU based on setpoints configured in the Linux device tree.

The following demonstrates how to read the setpoints for the imx6ul-var-dart with the 6.6-2.2.x-imx_var01 kernel branch, but is similar for all platforms and kernel versions:

cat /sys/class/thermal/thermal_zone0/trip_point_0_temp
cat /sys/class/thermal/thermal_zone0/trip_point_1_temp

For Commercial Operating Temperature SOC 

85000
90000

For Industrial Operating Temperature SOC 

95000
10000

The two thermal setpoints are calculated in the kernel drivers: https://github.com/varigit/linux-imx/blob/6.6-2.2.x-imx_var01/drivers/thermal/imx_thermal.c#L491-L492.