diff --git a/configs/Witherspoon.py b/configs/Witherspoon.py
index 40f82e2..8a306d6 100644
--- a/configs/Witherspoon.py
+++ b/configs/Witherspoon.py
@@ -294,6 +294,7 @@
         0x04 : '<inventory_root>/system/chassis/motherboard/pcielink',
         0xD8 : '/org/openbmc/sensors/host/PowerSupplyRedundancy',
         0xda : '/org/openbmc/sensors/host/TurboAllowed',
+        0xb4 : '/org/openbmc/sensors/host/PowerSupplyDerating',
     },
     'GPIO_PRESENT' : {}
 }
@@ -493,9 +494,10 @@
     0x02 : { 'class' : 'OperatingSystemStatusSensor' },
     0x06 : { 'class' : 'PowerCap',
         'os_path' : '/sys/class/hwmon/hwmon3/user_powercap' },
-    # Garrison value is used, need to get from P9 XML.
+    # Garrison value is used, Not in P9 XML yet.
     0xD8 : { 'class' : 'PowerSupplyRedundancySensor'},
     0xda : { 'class' : 'TurboAllowedSensor' },
+    0xb4 : { 'class' : 'PowerSupplyDeratingSensor' },
 }
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
diff --git a/pystatemgr/discover_system_state.py b/pystatemgr/discover_system_state.py
index b05af60..03eb84f 100644
--- a/pystatemgr/discover_system_state.py
+++ b/pystatemgr/discover_system_state.py
@@ -48,6 +48,11 @@
         'object_name': '/org/openbmc/sensors/host/TurboAllowed',
         'interface_name': 'org.openbmc.SensorValue'
     },
+    'powersupplyderating': {
+        'bus_name': 'org.openbmc.Sensors',
+        'object_name': '/org/openbmc/sensors/host/PowerSupplyDerating',
+        'interface_name': 'org.openbmc.SensorValue'
+    },
 }