meta-facebook: yosemite4: add airflow sensor

Summary:
Add airflow sensor by calcutating fans' RPM

Tested:
Check airflow sensor with different scenario
- Insert both fan board zero and one but only fan board one with fans
- Insert both fan board zero and one but only fan board zero with fans
- Remove fan board one and insert fan board zero but without fans
- Remove both fan board

Change-Id: I661c99ea9108a946e096697ff855a64c34da8840
Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>
diff --git a/meta-facebook/meta-yosemite4/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json b/meta-facebook/meta-yosemite4/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json
index dc9ce00..bf77e02 100644
--- a/meta-facebook/meta-yosemite4/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json
+++ b/meta-facebook/meta-yosemite4/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json
@@ -298,5 +298,101 @@
       ]
     },
     "Expression": "fan_vol * fan_curr"
+  },
+  {
+    "Desc": {
+      "Name": "SYSTEM_AIRFLOW",
+      "SensorType": "airflow"
+    },
+    "Params": {
+      "DbusParam": [
+        {
+          "ParamName": "P1",
+          "Desc": {
+            "Name": "FANBOARD0_FAN0_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P2",
+          "Desc": {
+            "Name": "FANBOARD0_FAN1_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P3",
+          "Desc": {
+            "Name": "FANBOARD0_FAN2_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P4",
+          "Desc": {
+            "Name": "FANBOARD0_FAN3_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P5",
+          "Desc": {
+            "Name": "FANBOARD0_FAN4_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P6",
+          "Desc": {
+            "Name": "FANBOARD0_FAN5_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P7",
+          "Desc": {
+            "Name": "FANBOARD1_FAN0_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P8",
+          "Desc": {
+            "Name": "FANBOARD1_FAN1_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P9",
+          "Desc": {
+            "Name": "FANBOARD1_FAN2_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P10",
+          "Desc": {
+            "Name": "FANBOARD1_FAN3_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P11",
+          "Desc": {
+            "Name": "FANBOARD1_FAN4_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        },
+        {
+          "ParamName": "P12",
+          "Desc": {
+            "Name": "FANBOARD1_FAN5_TACH_IL",
+            "SensorType": "fan_tach"
+          }
+        }
+      ]
+    },
+    "Expression": "(((P1 + P2 + P3 + P4 + P5 + P6 + P7 + P8 + P9 + P10 + P11 + P12) / 12) * 0.0687) - 8.0087"
   }
-]
\ No newline at end of file
+]
+