====== Build testptp on Debian ======
Applies to Debian-based distros too.

  - Install build-essential and kernel source <code>sudo apt install linux-source build-essential</code>
  - Decompress kernel source <code>cd /usr/src ;
sudo tar -xf linux-source-5.10.tar.xz</code>
  - Build! <code>cd /usr/src/linux-source-5.10/tools/testing/selftests/ptp ;
gcc -static testptp.c -o testptp</code>
  - Optional - install <code>mv testptp /usr/bin/.</code>
  - Test! <code>$ sudo testptp /dev/ptp0 -c
capabilities:
  62499999 maximum frequency adjustment (ppb)
  0 programmable alarms
  2 external time stamp channels
  2 programmable periodic signals
  1 pulse per second
  4 programmable pins
  0 cross timestamping
  0 adjust_phase</code>