Hello,
is there a sample devtree for the jetson nano devkit where the fan is controlled by the kernel driver based on the current temperature (i.e. similarly to Xavier NX)?
I’m understanding all that’s required is changes in devtree to configure “quite” / “cool” fan profiles (without having to change kernel config).
hello skrilax,
please access L4T sources from download center;
you may refer to below device tree settings for Nano’s thermal estimation.
i.e. $L4T_Sources/r32.4.3/T210/Linux_for_Tegra/source/public/hardware/nvidia/platform/t210/porg/kernel-dts/porg-platforms/tegra210-porg-thermal-fan-est.dtsi
please also note that,
it’s by default looking-up pwm_rpm_table by sending PWM signal to fan device for determine the fan speed;
please check hardware monitor for this look-up table.
for example,
$ cat /sys/class/hwmon/hwmon*/name
thermal-fan-est
tegra_pwmfan
$ cat /sys/class/hwmon/hwmon1/pwm_rpm_table
(Index, RPM, PWM, RRU, RRD)
(0, 0, 0, 40, 40)
(1, 1000, 80, 2, 2)
(2, 2000, 120, 1, 1)
(3, 3000, 160, 1, 1)
(4, 4000, 255, 1, 1)
(5, 5000, 255, 1, 1)
(6, 6000, 255, 1, 1)
(7, 7000, 255, 1, 1)
(8, 10000, 255, 1, 1)
(9, 11000, 255, 1, 1)
you may also refer to Topic 82420 for more details of RRU and RRD; above pwm_rpm_table settings were defined in the device tree also,
for example,
$L4T_Sources/r32.4.3/T210/Linux_for_Tegra/source/public/hardware/nvidia/platform/t210/porg/kernel-dts/porg-platforms/tegra210-porg-pwm-fan.dtsi
here’s developer guide, you should also check Thermal Management session for more details.
thanks