add valve namespace to sensor value

The valve open status is being represented as a sensor value in
percentage units. Recently, Redfish introduced "valve" as a ReadingType
under the sensors schema [1]. This update aligns with that change by
adding support for monitoring the open/close status of water valves.

[1] https://github.com/openbmc/bmcweb/blob/master/redfish-core/schema/dmtf/json-schema/Sensor.v1_11_0.json#L201

Change-Id: I59fd4bd1d510b89ec5edd923b9fe71f99c3985c1
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml b/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml
index a2b0a0e..3222fc0 100644
--- a/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml
+++ b/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml
@@ -14,6 +14,7 @@
       pressure
       temperature
       utilization
+      valve
       voltage
 
     Any service implementing Sensor.Value on one or more objects must implement
@@ -53,7 +54,8 @@
           "DegreesC". For objects in the utilization namespace, Unit must be
           "Percent" For objects in the voltage namespace, Unit must be "Volts",
           For objects in the liquidflow namespace, Unit must be "LPM". For
-          objects in the frequency namespace, Unit must be "Hertz".
+          objects in the frequency namespace, Unit must be "Hertz". For objects
+          in the valve namespace, Unit must be "Percent".
 
 enumerations:
     - name: Unit
@@ -145,5 +147,10 @@
             value: temperature
           - name: Utilization
             value: utilization
+          - name: Valve
+            value: valve
+            description: >
+                This path segment implements the value interface for the valve,
+                representing its open status.
           - name: Voltage
             value: voltage