tparys

Serial port devices starting with tty are often times are owned by root, but group dialout. If that's the case, the easiest is to add your user to the dialout group. Should be something along the lines of (but check "man usermod" before running it): $ sudo usermod -aG dialout <USERNAME> If the device is user and group root, you'll need to write a udev rule to set permissions when the kernel registers the device. Some brief reading material: https://stackoverflow.com/questions/14291431/change-ttyusb-permissions-using-udev#14292077 https://www.linuxquestions.org/questions/slackware-14/udev-rules-and-ttys0-device-644237/ Short version is that there's a few udev/rules.d directories, and you'll need to make a new rule file to match your KERNEL ttyAML0 device, and either assign ownership to your user, change group to dialout, or just make it world writable.

If the sysfs pwm device is showing up, I'm not following why you'd need libmraa to access it? If you'd like to have fewer moving parts, you should be able to do this entirely via DTB. I posted something similar for the fan on the NanoPI M4 metal case. https://forum.armbian.com/topic/17022-automatic-kernel-control-of-nanopi-m4-m4v2-metal-case-fan/ It was based on some earlier work the Kobol guys did for one of their NAS systems. You basically define the PWM as a fan control, give it a few operating levels, and tell the kernel that it's a cooling device for the CPUs. I also learned that depending on the PWM frequency, it can also create audible tones, which may or may not be desirable. You can also have it play music too, should you be so entertained ... https://forum.armbian.com/topic/19050-playing-with-a-fan-on-an-nanopi-m4v2/