From 329c53fa36c7a9a77174df4a962e0542cb2adcd9 Mon Sep 17 00:00:00 2001 From: Aditya Prayoga Date: Fri, 16 Oct 2020 14:43:28 +0700 Subject: [PATCH] helios64: Added temp sensor and fancontrol to PWM page --- docs/helios64/pwm.md | 116 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 115 insertions(+), 1 deletion(-) diff --git a/docs/helios64/pwm.md b/docs/helios64/pwm.md index 7e101b3..e7aaecf 100644 --- a/docs/helios64/pwm.md +++ b/docs/helios64/pwm.md @@ -35,7 +35,7 @@ The term *duty cycle* describes the proportion of 'on' time to the regular inter ## PWM Fan Connector -![Fan Connector](/helios4/img/pwm/fan_connector.png) +![Fan Connector](/helios64/img/pwm/fan_connector.png) Connector Pinout @@ -45,3 +45,117 @@ Connector Pinout | 2 | 12V | Red | | 3 | Sense | Yellow | | 4 | Control | Blue | + +## Helios64 Temperature Sensors + +### SoC Temperature Sensor + +RK3399 has internal temperature sensor (TS-ADC) for monitoring die temperature. The system has two Temperature Sensors, channel 0 is for CPU, channel 1 is for GPU. + +The sensor has -40~125°C temperature range and 5°C temperature resolution. + +### Board Temp Sensor + +Helios64 has a **Digital Temperature Sensor with 2‐wire Interface** ([NCT75 Datasheet](https://www.onsemi.com/pub/Collateral/NCT75-D.PDF)), located on top side of the board near RTC battery. It is used to read ambient temperature. + +## PWM Fan Control under Linux + +Linux use 8-bit integer to represent duty cycle. PWM value 0 represent 0% duty cycle and PWM value 255 represent 100% duty cycle. + +### Using SYSFS interface + +Linux export the fan control mechanism to SYSFS under hwmon class. +List of devices can be checked under /sys/class/hwmon + +``` +ls -l /sys/class/hwmon/ +total 0 +lrwxrwxrwx 1 root root 0 Oct 16 08:38 hwmon0 -> ../../devices/virtual/thermal/thermal_zone0/hwmon0 +lrwxrwxrwx 1 root root 0 Oct 16 08:38 hwmon1 -> ../../devices/virtual/thermal/thermal_zone1/hwmon1 +lrwxrwxrwx 1 root root 0 Oct 16 08:38 hwmon2 -> ../../devices/platform/ff120000.i2c/i2c-2/2-004c/hwmon/hwmon2 +lrwxrwxrwx 1 root root 0 Oct 16 09:29 hwmon3 -> ../../devices/platform/gpio-charger/power_supply/gpio-charger/hwmon3 +lrwxrwxrwx 1 root root 0 Oct 16 09:29 hwmon4 -> ../../devices/platform/p7-fan/hwmon/hwmon4 +lrwxrwxrwx 1 root root 0 Oct 16 09:29 hwmon5 -> ../../devices/platform/p6-fan/hwmon/hwmon5 +lrwxrwxrwx 1 root root 0 Oct 16 09:29 hwmon6 -> ../../devices/platform/ff3d0000.i2c/i2c-4/4-0022/power_supply/tcpm-source-psy-4-0022/hwmon6 +``` + +!!! info + The numbering may different from above example output. It depends on whether the driver built as kernel module or built-in, device initialization order. Take this as consideration when using [fancontrol](#fancontrol-automated-software-based-fan-speed-control) + +To identify which hwmon belong to fan, look for *p6-fan* and *p7-fan*. On above example + +``` +hwmon4 -> ../../devices/platform/p7-fan/hwmon/hwmon4 +hwmon5 -> ../../devices/platform/p6-fan/hwmon/hwmon5 +``` + +To read current PWM +``` +cat /sys/class/hwmon4/pwm1 +cat /sys/class/hwmon5/pwm1 +``` + +To set PWM +``` +echo NEW_PWM_VALUE > /sys/class/hwmon4/pwm1 +echo NEW_PWM_VALUE > /sys/class/hwmon5/pwm1 +``` + +### Fancontrol - automated software based fan speed control + +fancontrol is a shell script for use with lm_sensors. It reads its configuration from a file, then calculates fan speeds from temperatures and sets the corresponding PWM outputs to the computed values. + +``` +sudo apt-get install fancontrol +``` + +fancontrol includes *pwmconfig* script to create automatically a configuration file but it can not be used for Helios64. + +#### UDEV rules + +Since hwmon order can be changed between kernel version or even between reboot, on Armbian we use udev rules as workaround. The rules can be found from [here](https://raw.githubusercontent.com/armbian/build/master/packages/bsp/helios64/90-helios64-hwmon.rules) (mainline) or [here](https://raw.githubusercontent.com/armbian/build/master/packages/bsp/helios64/90-helios64-hwmon-legacy.rules) (legacy kernel 4.4) and to be copied to **/etc/udev/rules.d/** + +*/dev/fan-p6, /dev/fan-p7, /dev/thermal-cpu* and */dev/thermal-board* are symlinks generated by the udev rules. + +#### Configuration File + +fancontrol uses **/etc/fancontrol** as configuration file. Below is an example configuration to control fan speed on Helios64. + +``` +# Helios64 PWM Fan Control Configuration +# Temp source : /dev/thermal-cpu +INTERVAL=10 +FCTEMPS=/dev/fan-p6/pwm1=/dev/thermal-cpu/temp1_input /dev/fan-p7/pwm1=/dev/thermal-cpu/temp1_input +MINTEMP=/dev/fan-p6/pwm1=40 /dev/fan-p7/pwm1=40 +MAXTEMP=/dev/fan-p6/pwm1=80 /dev/fan-p7/pwm1=80 +MINSTART=/dev/fan-p6/pwm1=60 /dev/fan-p7/pwm1=60 +MINSTOP=/dev/fan-p6/pwm1=29 /dev/fan-p7/pwm1=29 +MINPWM=20 +``` + +INTERVAL + +This variable defines at which interval in seconds the main loop of fancontrol will be executed. + +FCTEMPS + +Maps PWM outputs to temperature sensors so fancontrol knows which temperature sensors should be used for calculation of new values for the corresponding PWM outputs. + +Fans (**fan-p6** & **fan-p7**) are controlled based on CPU thermal sensor (**thermal-cpu**) reading. + +----- + +*Following settings can be adjusted by user to tweak further.* + +MINTEMP + +The temperature below which the fan gets switched to minimum speed. + +Fans (fan-p6 & fan-p7) runs in minimum speed if the CPU temperature below **40** degree C. + +MAXTEMP + +The temperature over which the fan gets switched to maximum speed. + +Fans (fan-p6 & fan-p7) runs in maximum speed if the CPU temperature above **80** degree C. +