Where is the temp sensor that lm-sensors 'sensor' returns?

VisionFive 2 （English Forum)
1

I have installed lm-sensors and run ‘sensors’:
user@starfive1:~$ sensors
120e0000.tmon-isa-0000
Adapter: ISA adapter
temp1: +53.4°C

Also, a near-question’s answer says look at ‘/sys/class/hwmon/hwmon0/temp1_input’:
user@starfive1:~$ cat /sys/class/hwmon/hwmon0/temp1_input
53429

Clearly the same sensor, but what one? CPU temp? Board temp?

Too lazy to find and slog through whatever doci there is… Thought someone might already know.
TIA

2

I would say the JH7110 RISC-V SoC temperature.
My search for “kernel hwmon StarFive JH7110” resulted in the following.
Kernel driver sfctemp

4 Likes
3

Thank you very much. That makes a lot of sense to be the SoC’s temp.

On a second StarFive 2, I have the “WayPonDEV Acrylic Case for VisionFive2 RISC-V Linux Single Board Computer (with Heat Sink)” from Amazon (actually by Youyeetoo). Perfect case. Comes with a not-so-quiet 5v fan that snaps onto the board over the SoC, and plugs into the 5v fan power socket. That system runs MUCH cooler, but it runs off an SD card, while the 53.4 degree C has no case or fan and runs off an M.2 NVMe (which I’m sure is tranferring heat to the SoC).

Thanks again.

4 
cat /sys/class/thermal/thermal_zone0/temp
1 Like
5

Bit of fun for temp controlling the pwm for a cpu fan. The /10 works for my little cpu fan, but limit and scale have to be worked out for another fan. Don’t think it relies on lm-sensors. Put a fet between the pwm0 pin and fan 5v.

# m h dom mon dow command (every minute)
0/1 * * * * echo $((cat /sys/class/thermal/thermal_zone0/temp/10)) > /sys/class/pwm/pwmchip0/pwm0/duty_cycle