labgrid/driver/power: depcrecate siglent backend

See labgrid-project#1507 for more
details.

Signed-off-by: Bastian Krause <bst@pengutronix.de>

labgrid/driver/power/siglent.py

@@ -1,9 +1,16 @@
 """ tested with Siglent SPD3303X-E, and should be compatible with all SPD3000X series modules"""
 
+import warnings
+
 import vxi11
 
 
 def power_set(host, port, index, value):
+    warnings.warn(
+        "siglent power backend uses vxi11 module using deprecated xdrlib module, see https://github.com/labgrid-project/labgrid/issues/1507",
+        DeprecationWarning,
+    )
+
     assert port is None
     index = int(index)
     assert 1 <= index <= 2
@@ -13,6 +20,11 @@ def power_set(host, port, index, value):
 
 
 def power_get(host, port, index):
+    warnings.warn(
+        "siglent power backend uses vxi11 module using deprecated xdrlib module, see https://github.com/labgrid-project/labgrid/issues/1507",
+        DeprecationWarning,
+    )
+
     assert port is None
     index = int(index)
     assert 1 <= index <= 2