mcu: Add support for connecting to devices on a CAN bus

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/canbus_ids.py

@@ -0,0 +1,24 @@
+# Support for tracking canbus node ids
+#
+# Copyright (C) 2021  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+class PrinterCANBus:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.ids = {}
+    def add_uuid(self, config, canbus_uuid, canbus_iface):
+        if canbus_uuid in self.ids:
+            raise config.error("Duplicate canbus_uuid")
+        new_id = len(self.ids)
+        self.ids[canbus_uuid] = new_id
+        return new_id
+    def get_nodeid(self, canbus_uuid):
+        if canbus_uuid not in self.ids:
+            raise self.printer.config_error("Unknown canbus_uuid %s"
+                                            % (canbus_uuid,))
+        return self.ids[canbus_uuid]
+
+def load_config(config):
+    return PrinterCANBus(config)