[BPI-R2] Recent OpenWrt snapshots break temperature monitoring

Banana Pi Router design
1

It appears that recent snapshots of OpenWrt break CPU temperature monitoring:

22.03.02:

root@OpenWrt:/sys# cat /sys/devices/virtual/thermal/thermal_zone0/temp
48961

SNAPSHOT:

root@OpenWrt:/sys# cat /sys/devices/virtual/thermal/thermal_zone0/temp
0

Has anyone else noticed this?

2

Which kernelversion do you have there? My vanilla kernel 5.15.63 (mhm…time for upgrade :slight_smile: uptime 86 days ) does not have this bug.

3

Latest OpenWrt snapshot is 5.15.78. What are you running that uses a vanilla kernel?

4

I do not use openwrt,but i guess it is a openwrt specific issue (maybe due to backports)

5

mainline do not have this issue (or already fixed)

root@bpi-r2:~# cat /sys/class/thermal/thermal_zone0/temp
34891
root@bpi-r2:~# uname -a
Linux bpi-r2 5.15.80-bpi-r2-main #2 SMP Mon Nov 28 17:56:27 CET 2022 armv7l GNU/Linux

maybe you miss any config option (efuse or adc)?

do not see any related commits in drivers/thermal, drivers/nvmem, drivers/iio/adc between 5.15.78 and 5.15.80

6

Installing kmod-iio-mt6577-auxadc fixes the issue for now, but that’s not a good solution. I’ll push a fix again having this driver as built-into the kernel in a few moments.

Edit: It’s weird that this seems to be needed only on MT7623 while other MediaTek SoCs (MT7622, MT7986) correctly report temperature even without the mt6577_auxadc being loaded.

7

And it’s only on snapshot. On 22.03.2 the 7623 reports its temperature with no problems.

8

Yep, it was caused by my commit

This commit is only present in the master branch and not in openwrt-22.03 or earlier releases.

And I’ve now fixed it with

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