[Edgecore][device][platform] psu-fan direction get N/A when it is pow…

…er_good= failed.

Signed-off-by: michael_shih <michael_shih@edge-core.com>

platform/broadcom/sonic-platform-modules-accton/as9736-64d/sonic_platform/fan.py

@@ -82,7 +82,20 @@ def get_direction(self):
                 direction=self.FAN_DIRECTION_EXHAUST
 
         else: #For PSU
-            direction=self.FAN_DIRECTION_EXHAUST
+            psu_path = "{}{}".format(self.psu_cpld_path, 'psu_power_good')
+            val = self._api_helper.read_txt_file(psu_path)
+            if val is None or int(val, 10)==0:
+                return self.FAN_DIRECTION_NOT_APPLICABLE
+
+            dir_str = "{}{}".format(self.psu_hwmon_path,'psu_fan_dir')
+            val=self._api_helper.read_txt_file(dir_str)
+            if val is None or val == "":
+                return self.FAN_DIRECTION_EXHAUST
+            else:
+                if val=='F2B':
+                    direction=self.FAN_DIRECTION_EXHAUST
+                else:
+                    direction=self.FAN_DIRECTION_INTAKE
 
         return direction