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Taurolyon / rp64_fan

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Armbian /sys pointers #1

Open Taurolyon opened 1 year ago

Taurolyon commented 1 year ago 
[jay@rockpro64 pwm]$ pwd
/sys/class/pwm
[jay@rockpro64 pwm]$ ls
total 0
drwxr-xr-x  2 root 0 Jan 21 03:06 .
drwxr-xr-x 75 root 0 Jan 21 03:06 ..
lrwxrwxrwx  1 root 0 Jan 21 03:06 pwmchip0 -> ../../devices/platform/ff420000.pwm/pwm/pwmchip0
lrwxrwxrwx  1 root 0 Jan 21 03:06 pwmchip1 -> ../../devices/platform/ff420010.pwm/pwm/pwmchip1
lrwxrwxrwx  1 root 0 Jan 21 03:06 pwmchip2 -> ../../devices/platform/ff420020.pwm/pwm/pwmchip2
[jay@rockpro64 pwm]$ ls */
pwmchip0/:
total 0
drwxr-xr-x 3 root    0 Jan 21 03:06 .
drwxr-xr-x 3 root    0 Jan 21 03:06 ..
lrwxrwxrwx 1 root    0 Jan 21 03:10 device -> ../../../ff420000.pwm
--w------- 1 root 4.0K Jan 21 03:10 export
-r--r--r-- 1 root 4.0K Jan 21 03:10 npwm
drwxr-xr-x 2 root    0 Jan 21 03:06 power
lrwxrwxrwx 1 root    0 Jan 21 03:06 subsystem -> ../../../../../class/pwm
-rw-r--r-- 1 root 4.0K Jan 21 03:06 uevent
--w------- 1 root 4.0K Jan 21 03:10 unexport

pwmchip1/:
total 0
drwxr-xr-x 3 root    0 Jan 21 03:06 .
drwxr-xr-x 3 root    0 Jan 21 03:06 ..
lrwxrwxrwx 1 root    0 Jan 21 03:10 device -> ../../../ff420010.pwm
--w------- 1 root 4.0K Jan 21 03:10 export
-r--r--r-- 1 root 4.0K Jan 21 03:10 npwm
drwxr-xr-x 2 root    0 Jan 21 03:06 power
lrwxrwxrwx 1 root    0 Jan 21 03:06 subsystem -> ../../../../../class/pwm
-rw-r--r-- 1 root 4.0K Jan 21 03:06 uevent
--w------- 1 root 4.0K Jan 21 03:10 unexport

pwmchip2/:
total 0
drwxr-xr-x 3 root    0 Jan 21 03:06 .
drwxr-xr-x 3 root    0 Jan 21 03:06 ..
lrwxrwxrwx 1 root    0 Jan 21 03:10 device -> ../../../ff420020.pwm
--w------- 1 root 4.0K Jan 21 03:10 export
-r--r--r-- 1 root 4.0K Jan 21 03:10 npwm
drwxr-xr-x 2 root    0 Jan 21 03:06 power
lrwxrwxrwx 1 root    0 Jan 21 03:06 subsystem -> ../../../../../class/pwm
-rw-r--r-- 1 root 4.0K Jan 21 03:06 uevent
--w------- 1 root 4.0K Jan 21 03:10 unexport

Periodically, a pwm0 folder will appear on boot, and can be controlled by a script, but it doesn't persist.

If it is present, it's possible to control it using a script (without active thermal control) as mentioned in this forum post.

Taurolyon commented 1 year ago 
find /sys/devices/ -name "pwm1"