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.
