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André Valentin
f29dfe25ba
The NBG7815 cools itself with a GPIO driven fan on TLMM 21. A second
tmp103 sits on the second I2C bus (BLSP QUP4), which the stock firmware
reads as the board temperature, and the stock firmware keeps GPIO 22
high to enable the second fan.
The switching points come from the stock firmware, which controls the
fan from a shell daemon /usr/sbin/fanctld, configured in
/etc/config/fanctld:
config fanctld config
option Enabled '1'
option Delay '20'
option Hits '3'
option TempTrig '108'
option TempClr '85'
fanctld polls every 20 s and starts the fan once any of thermal_zone0
(nss-top), wifi0 or wifi1 has been at or above TempTrig for three
consecutive polls. It stops the fan again only after all three have been
at or below TempClr for three polls:
if [ $temp1 -ge $temp_trig -o $temp2 -ge $temp_trig -o $temp3 -ge $temp_trig ]; then
echo 2
elif [ $temp1 -le $temp_clr -a $temp2 -le $temp_clr -a $temp3 -le $temp_clr ]; then
echo 1
The trip is placed at 85 degC with 5 degC hysteresis, so the fan runs
from 85 degC and stops again at 80 degC, rather than at the stock 108/85:
the SoC hardly reaches 108, so the case gets uncomfortably hot under load
before the fan would ever start, as reported for this device in
https://github.com/openwrt/openwrt/pull/14210
It sits on the CPU cluster rather than on the sensors the stock daemon
polls: the wifi sensors are only reachable through the vendor thermaltool
there, and one zone is enough to drive the fan.
Add the gpio-fan as a cooling device with that trip, enable the second
I2C bus with its tmp103, add the gpio-hog for the second fan enable and
describe the USB VBUS switch on GPIO 32 as a regulator rather than
hogging it.
That regulator carries enable-active-high. For regulator-fixed, gpiolib
ignores the flag in the GPIO specifier and takes the line as active low
without that property, so the regulator would drive GPIO 32 low at probe
- logged as "enforce active low on GPIO handle" - while the stock
firmware holds the line high.
The AQR PHY is deliberately left out of the cooling maps: its driver
rejects the low trip the thermal core installs by default, so a thermal
zone bound to it fails to set its trips.
Co-developed-by: Semih Baskan <strst.gs@gmail.com>
Signed-off-by: Semih Baskan <strst.gs@gmail.com>
Signed-off-by: André Valentin <avalentin@marcant.net>