Added Doxygen documentation

.github/workflows/ci.yml

@@ -89,3 +89,26 @@ jobs:
 
       - name: Run tests on native environment
         run: platformio test --environment native -vvv
+
+  # Build documentation
+  doc:
+    # The type of runner that the job will run on.
+    runs-on: ubuntu-latest
+    needs: intro
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v3
+
+    - name: Set up graphviz
+      uses: ts-graphviz/setup-graphviz@v1.2.0
+
+    - name: Set up doxygen and generate documentation for SerialMuxProt
+      uses: mattnotmitt/doxygen-action@v1.9.5
+      with:
+        working-directory: './doc/doxygen'
+        doxyfile-path: './Doxyfile'
+
+    - name: Print doxygen warnings
+      if: ${{ failure() }}
+      run: cat ./doc/doxygen/doxygen_warnings.txt

doc/doxygen/.gitignore

@@ -0,0 +1 @@
+*/html/*