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SoC Thermal Temperature

Reading the SOC Temperature

The i.MX 8 QuadMax/QuadPlus SOC has an internal temperature sensor that can be read. The temperature is reported in millidegrees Celsius:

root@imx8qm-var-som:~# cat /sys/class/thermal/thermal_zone*/temp
70000
57600
57900
57900
59100
57000

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 imx8qm-var-som with the lf-6.6.y_6.6.52-2.2.0_var01 kernel branch, but is similar for all platforms and kernel versions:

root@imx8qm-var-som:~# cat /sys/class/thermal/thermal_zone*/trip_point_1_temp
125000
127000
127000
127000
127000
127000

As shown above, there are two thermal setpoints, 125C and 127C. The setpoints are configured in the device tree: https://github.com/varigit/linux-imx/blob/lf-6.6.y_6.6.52-2.2.0_var01/arch/arm64/boot/dts/freescale/imx8qm.dtsi#L405.