iMX8MQ thermal setting - industrial

[CHOIzee]

Hi, I'm using i.MX8mq processor.

As I know, the industrial processor can work in -40 ~ 120 degree.

So I test it with my temperature testing apparatus.

When I run the processor, in -40 degree, it can not work well. (The error occurred during -30 degree too)

In boot process, it can not read its thermal normally cuz the temperature sensor can not measure under 0 degree.

I understand it can not measure under 0 degree, but I think it must work well even it can not measure it.

Because of thermal error, processor can not boot. It measured its thermal as 115 degree(above critical point), not sub-zero. If the thermal sensor work well, it must alarm the low temperature but there is no alarm about low temperature. Boot log shows 115 degree value in -30 ~ -40 degree.

So what I want to know is

How to config my kernel, if I want to boot my processor well in under 0 degree.

[igorpadykov]

Hi JiHwan

>I understand it can not measure under 0 degree, but I think it must work well even it can not measure it.

nxp thermal driver (..drivers/thermal/qoriq_thermal.c) correctly handles this case, one can look

at function tmu_get_temp():

REGS_TRITSR(id) has the following layout:
*
* For TMU Rev1:
* 31 ... 7 6 5 4 3 2 1 0
* V TEMP
*
* Where V bit signifies if the measurement is ready and is
* within sensor range..

https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/thermal/qoriq_thermal.c?h=lf-5.10....

Description can be found in sect.5.4.3.16 TMU report immediate temperature site register

i.MX 8M Dual/8M QuadLite/8M Quad Applications Processors Reference Manual

sect.2.9 Thermal  i.MX Linux Reference Manual​

Best regards
igor