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Linux/TMDX654IDKEVM: Temperature reading

Silviu Balan
Expert 1620 points
Part Number: TMDX654IDKEVM


Tool/software: Linux

Hello,

I want to read the temperature of the sensors on my board. 

In the /sys/class/thermal folder I found 3 thermal zones (thermal_zone0/1/2) and I can read temperatures from there.

What temperatures are measured for this 3 zones?

Thank you!

  • 0
    TI__Guru**** 170625 points

    Hi Silviu,

    These seems to be MPU0, MPU1 and MCU. Please check DTS file am654-industrial-thermal.dtsi.

    You can also verify this by reading (use "cat" command) some thermal_zonex node or property. Refer to below TXT fiels for details:

    linux-4.14.79/Documentation/devicetree/bindings/thermal/thermal.txt

    linux-4.14.79/Documentation/thermal/sysfs-api.txt

    Below e2e thread is for AM57x device, but some aspects are also valid for AM65x device:

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    Expert 1620 points

    Hello,

    Thanks for your answer.

    1. In sysfs-api.txt I found that hwmon sysfs I/F extension is available under /sys/class/hwmon. I checked this directory and it is empty. Can you tell me why?

    2. Can you confirm that: 

    • MPU1 refers to M3 processor,
    • MPU2 refers to A53 processor and
    • MCU refers to R5 controller?

    3. How can I know which thermal zone is for each MPU1, MP2 and MCU?

    Best regards!

  • 0 in reply to Silviu Balan
    TI__Guru**** 170625 points

    Silviu,

    You can check which thermal zone correspond to what from the "type" node:

    root@am65xx-evm:/sys/class/thermal/thermal_zone0# cat type
    mpu0_thermal

    root@am65xx-evm:/sys/class/thermal/thermal_zone1# cat type
    mpu1_thermal

    root@am65xx-evm:/sys/class/thermal/thermal_zone2# cat type
    mcu_thermal

    Per mine understanding, these correspond to:

    thermal_zone0 -> mpu0_thermal -> Cortex-A53 MPU0 -> CC_ARMSS0

    thermal_zone1 -> mpu1_thermal -> Cortex-A53 MPU1 -> CC_ARMSS1

    thermal_zone2 -> mcu_thermal -> Cortex-R5F MCU -> MCU_ARMSS

    Regards,
    Pavel