Tegra Tx2 Fan PWM driver Pwm control on the basis of temperature

[shubhangini.g]

Hi ALL,

We looking forward for a little detail on how the fan pwm is controlled on the basis of thermal temperature. From the kernel driver logs we got the mapping as :

[ 10.037065] pwm_fan_driver pwm-fan: index 0: pwm=0, rpm=0, rru=40, rrd=40, state:2
[ 10.044647] pwm_fan_driver pwm-fan: index 1: pwm=80, rpm=1000, rru=2, rrd=2, state:2
[ 10.052405] pwm_fan_driver pwm-fan: index 2: pwm=120, rpm=2000, rru=1, rrd=1, state:2
[ 10.060243] pwm_fan_driver pwm-fan: index 3: pwm=160, rpm=3000, rru=1, rrd=1, state:2
[ 10.068084] pwm_fan_driver pwm-fan: index 4: pwm=255, rpm=4000, rru=1, rrd=1, state:3
[ 10.075924] pwm_fan_driver pwm-fan: index 5: pwm=255, rpm=5000, rru=1, rrd=1, state:3
[ 10.083766] pwm_fan_driver pwm-fan: index 6: pwm=255, rpm=6000, rru=1, rrd=1, state:3
[ 10.091607] pwm_fan_driver pwm-fan: index 7: pwm=255, rpm=7000, rru=1, rrd=1, state:4
[ 10.099443] pwm_fan_driver pwm-fan: index 8: pwm=255, rpm=10000, rru=1, rrd=1, state:4
[ 10.107366] pwm_fan_driver pwm-fan: index 9: pwm=255, rpm=11000, rru=1, rrd=1, state:4

Can some one please let me know how these indexes will be set on the basis of temperature.

Thanks

[JerryChang]

hello shubhangini.g,

there’s hardware monitor, you may check /sys/class/hwmon/hwmon*/name for its usage.
for example, it’s hwmon2 for pwm-fan,

$ cat /sys/class/hwmon/hwmon2/name
tegra_pwmfan

you may looking for pwm_rpm_table, it’s a look-up-table for PWM controlling values and its fan rotate speed,