I'm trying to get my DC motor to work according to this tutorial from Adafruit:

I'm running Occidentalis v0.2 (from day 1, which was some 4 months ago) and never had a similar issue. This is the problem:

$ sudo ls /sys/class/rpi-pwm
ls: cannot access /sys/class/rpi-pwm: No such file or directory


$ ls -lR /sys/class | grep -c rpi-pwm

Seems PWM kernel module is not installed!? How come and how can I fix that, please?


I had the same problem after doing an update. The entire pwm and servo module has disappeared. Maybe because it is a kernel module and the update pulled in a new (non-occidentalis kernel).

Anyway, I fixed it by putting the old kernel back. You can find instructions on how to do that in the details page for Occicentalis v.02, last section at the bottom: Kernel Source.

Basically you need to download their Kernel+Modules tgz file, extract it and install it by copying the files:

  • tar -zxvf mykernel.tgz
  • sudo cp tmp/kernel.img /boot/
  • sudo cp -R tmp/modules/lib/* /lib/
  • rm -rf tmp

Then reboot and /sys/class/rpi-pwm should be present again.

  • Sounds sensible. I'll check it and let you know.
    – Saran
    Mar 18 '14 at 14:02
  • Great walkthrough, @Whiskey. New output: sudo ls /sys/class/rpi-pwm pwm0. Now I just have to remember what I needed that 4 months ago for ^_^
    – Saran
    May 25 '14 at 15:00

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