Docs: Enable RTD on tf-m-extras

Added files required for the tf-m-extras documentation to be displayed on Read the Docs.

Change-Id: I813589f566b58834dc75142b7a92349589d8da87
Signed-off-by: Elena Uziunaite <elena.uziunaite@arm.com>
diff --git a/docs/conf.py b/docs/conf.py
new file mode 100644
index 0000000..da80cd3
--- /dev/null
+++ b/docs/conf.py
@@ -0,0 +1,157 @@
+# -*- coding: utf-8 -*-
+#-------------------------------------------------------------------------------
+# Copyright (c) 2019-2022, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+
+# Configuration file for the Sphinx documentation builder.
+#
+# This file does only contain a selection of the most common options. For a
+# full list see the documentation:
+# http://www.sphinx-doc.org/en/master/config
+
+import os
+import sys
+import re
+from subprocess import check_output
+
+# -- Project information -----------------------------------------------------
+
+project = 'Trusted Firmware-M Extras'
+copyright = '2023, ARM CE-OSS'
+author = 'ARM CE-OSS'
+title = 'User Guide'
+
+# -- Extract current version -------------------------------------------------
+
+try:
+    vrex = re.compile(r'TF-M(?P<GIT_VERSION>v.+?)'
+                      r'(-[0-9]+-g)?(?P<GIT_SHA>[a-f0-9]{7,})?$')
+
+    version = check_output("git describe --tags --always",
+                            shell = True, encoding = 'UTF-8')
+
+    _v = vrex.match(version)
+    release = _v.group('GIT_VERSION')
+    if _v.group('GIT_SHA'):
+        version = release + "+" + _v.group('GIT_SHA')[:7]
+
+except:
+    version = release = 'Unknown'
+
+# -- General configuration ---------------------------------------------------
+
+extensions = [
+    'sphinx.ext.imgmath',
+    'm2r2', #Support markdown files. Needed for external code.
+    'sphinx.ext.autosectionlabel', #Make sphinx generate a label for each section
+    'sphinxcontrib.plantuml', #Add support for PlantUML drawings
+    'sphinxcontrib.rsvgconverter', #Add support for SVG to PDF
+    'sphinx_tabs.tabs', #Enable tab extension in Sphinx
+]
+
+# Make auto section labels generated be prefixed with file name.
+autosectionlabel_prefix_document=True
+# Add auto section label for level 2 headers only.
+autosectionlabel_maxdepth=2
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# The suffix(es) of source filenames.
+# You can specify multiple suffix as a list of string:
+#
+source_suffix = ['.rst', '.md']
+
+# The master toctree document.
+master_doc = 'index'
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#
+# This is also used if you do content translation via gettext catalogs.
+# Usually you set "language" from the command line for these cases.
+language = None
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path .
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store', 'readme.rst',
+                    'platform/cypress/psoc64/security/keys/readme.rst',
+                    'lib/ext/**']
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = 'sphinx'
+
+# -- Options for HTML output -------------------------------------------------
+
+html_theme = 'sphinx_rtd_theme'
+
+html_theme_options = {
+    'collapse_navigation' : False,
+    'prev_next_buttons_location' : None,   # Hide Prev and Next buttons
+    'display_version': True,    # Show version under logo
+    'sticky_navigation': True,
+    'navigation_depth': 3,
+}
+
+# Remove the "View page source" link from the top of docs pages
+html_show_sourcelink = False
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to configuration directory. They are copied after the builtin static
+# files, so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
+
+# Set the documentation logo relative to configuration directory
+html_logo = '_static/images/tf_logo_white.png'
+
+# Set the documentation favicon
+html_favicon = '_static/images/favicon.ico'
+
+#Disable adding conf.py copyright notice to HTML output
+html_show_copyright = False
+
+# Disable showing Sphinx footer message:
+# "Built with Sphinx using a theme provided by Read the Docs. "
+html_show_sphinx = False
+
+#Add custom css for HTML. Used to allow full page width rendering
+def setup(app):
+    app.add_css_file('css/tfm_custom.css')
+
+# -- Options for HTMLHelp output ---------------------------------------------
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = 'TF-M doc'
+
+# Enable figures and tables auto numbering
+numfig = True
+numfig_secnum_depth = 0
+numfig_format = {
+    'figure': 'Figure %s:',
+    'table': 'Table %s:',
+    'code-block': 'Listing %s:',
+    'section': '%s'
+}
+
+# -- Options for LaTeX output ------------------------------------------------
+
+latex_elements = {
+    # 'papersize': 'letterpaper',
+    # 'pointsize': '10pt',
+    # 'preamble': '',
+    # 'figure_align': 'htbp',
+}
+
+# Grouping the document tree into LaTeX files. List of tuples
+# (source start file, target name, title,
+#  author, documentclass [howto, manual, or own class]).
+latex_documents = [
+    (master_doc, 'TF-M.tex', title,
+     author, 'manual'),
+]
+
+language = 'en'