Added support for "input" and "output" classes.

Signed-off-by: Maciej Kurc <mkurc@antmicro.com>

v2x/vlog_to_model.py

diff --git a/v2x/vlog_to_model.py b/v2x/vlog_to_model.py
index 0a0a7dc..faf2444 100755
--- a/v2x/vlog_to_model.py
+++ b/v2x/vlog_to_model.py
@@ -162,7 +162,7 @@
         ), "Leaf model names should be all uppercase!"
         modclass = tmod.attr("CLASS", "")
 
-        if modclass not in ("lut", "routing", "flipflop"):
+        if modclass not in ("input", "output", "lut", "routing", "flipflop"):
             model_xml = ET.SubElement(models_xml, "model", {'name': topname})
             ports = tmod.ports
 

v2x/vlog_to_pbtype.py

diff --git a/v2x/vlog_to_pbtype.py b/v2x/vlog_to_pbtype.py
index 66f100e..8164c63 100755
--- a/v2x/vlog_to_pbtype.py
+++ b/v2x/vlog_to_pbtype.py
@@ -9,8 +9,8 @@
     This will also set the BLIF model to be `.subckt <name>` unless CLASS is
     also specified.
 
-    - `(* CLASS="lut|routing|mux|flipflop|mem" *)` : specify the class of an
-    given instance.
+    - `(* CLASS="input|output|lut|routing|mux|flipflop|mem" *)` : specify
+    the class of an given instance.
 
     - `(* MODES="mode1; mode2; ..." *)` : specify that the module has more
     than one functional mode, each with a given name. The module will be
@@ -715,7 +715,11 @@
     ), "Model name should be uppercase. {}".format(model_name)
     mod_cls = mod.CLASS
     if mod_cls is not None:
-        if mod_cls == "lut":
+        if mod_cls == "input":
+            pb_attrs["blif_model"] = ".input"
+        elif mod_cls == "output":
+            pb_attrs["blif_model"] = ".output"
+        elif mod_cls == "lut":
             pb_attrs["blif_model"] = ".names"
             pb_attrs["class"] = "lut"
         elif mod_cls == "routing":