Modified RTD env to include submodules and build cell docs Signed-off-by: Wojciech Gryncewicz <wgryncewicz@antmicro.com>

diff --git a/.readthedocs.yml b/.readthedocs.yml
index 5321847..3ed0d3f 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml

@@ -31,4 +31,9 @@
 submodules:
   include:
    - libraries/sky130_fd_io/latest
+   - libraries/sky130_fd_sc_hd/latest
+   - libraries/sky130_fd_sc_hdll/latest
+   - libraries/sky130_fd_sc_hs/latest
+   - libraries/sky130_fd_sc_ls/latest
+   - libraries/sky130_fd_sc_ms/latest
   recursive: false

diff --git a/docs/_ext/skywater_pdk b/docs/_ext/skywater_pdk
new file mode 120000
index 0000000..c5fe58c
--- /dev/null
+++ b/docs/_ext/skywater_pdk

@@ -0,0 +1 @@
+../../scripts/python-skywater-pdk/skywater_pdk/
\ No newline at end of file

diff --git a/docs/conf.py b/docs/conf.py
index b817d54..e0e8107 100644
--- a/docs/conf.py
+++ b/docs/conf.py

@@ -31,9 +31,9 @@
 import docutils
 import os
 import re
-# import sys
+import sys
 # sys.path.insert(0, os.path.abspath('.'))
-
+sys.path.insert(0, os.path.abspath('./_ext'))
 
 # -- Project information -----------------------------------------------------
 
@@ -65,6 +65,8 @@
     'sphinx.ext.napoleon',
     'sphinx.ext.todo',
     'sphinxcontrib_hdl_diagrams',
+    'skywater_pdk.cells.cross_index',
+    'skywater_pdk.cells.generate.readme',
 ]
 
 # Add any paths that contain templates here, relative to this directory.

diff --git a/docs/contents/cell-index.rst b/docs/contents/cell-index.rst
new file mode 100644
index 0000000..32b025b
--- /dev/null
+++ b/docs/contents/cell-index.rst

@@ -0,0 +1,3 @@
+.. generate_cell_readme:: libraries/*/cells/*
+
+.. cross_index:: libraries/*

diff --git a/docs/contents/libraries.rst b/docs/contents/libraries.rst
index ca3c24e..0b1f8aa 100644
--- a/docs/contents/libraries.rst
+++ b/docs/contents/libraries.rst

@@ -146,3 +146,8 @@
 
     libraries/sky130_ef_io/README
 
+.. toctree::
+    :maxdepth: 1
+    :name: Cells in libraries cross-index
+
+    cell-index