[device]: Fix a bug that psuutil cannot access gpio sysfs to get PSU …

…status (sonic-net#1789)

device/celestica/x86_64-cel_seastone-r0/plugins/psuutil.py

@@ -3,7 +3,8 @@
 # Platform-specific PSU status interface for SONiC
 #
 
-import os.path
+import os
+
 
 try:
     from sonic_psu.psu_base import PsuBase
@@ -18,42 +19,32 @@ def __init__(self):
         PsuBase.__init__(self)
         # DX010 PSU pin mapping
         self.psu = [
-            {'base':216},           # Reserved
+            {'base': self.get_gpio_base()},
             {'abs':27, 'power':22},
             {'abs':28, 'power':25}
         ]
 
-    def init_psu_gpio(self, pinnum):
-        # export pin, input as default
-        gpio_base = self.psu[0]['base']
-        export_file = "/sys/class/gpio/export"
-        direction_file = '/sys/class/gpio/gpio' + str(gpio_base+pinnum) + '/direction' 
-
-        try:
-            with open(export_file, 'w') as fd:
-                fd.write(str(gpio_base+pinnum))
-        except Exception as error:
-            logging.error("Unable to export gpio ", pinnum)
+    def get_gpio_base(self):
+        sys_gpio_dir = "/sys/class/gpio"
+        for r in os.listdir(sys_gpio_dir):
+            if "gpiochip" in r:
+                return int(r[8:],10)
+        return 216 #Reserve
 
 
     # Get a psu status and presence
     def read_psu_statuses(self, pinnum):
         sys_gpio_dir = "/sys/class/gpio"
-        retval = 'ERR'
         gpio_base = self.psu[0]['base']
 
         gpio_dir = sys_gpio_dir + '/gpio' + str(gpio_base+pinnum)
         gpio_file = gpio_dir + "/value"
-
-        # init gpio 
-        if (not os.path.isdir(gpio_dir)):
-            self.init_psu_gpio(pinnum)
 
         try:
             with open(gpio_file, 'r') as fd:
                 retval = fd.read()
-        except Exception as error:
-            logging.error("Unable to open ", gpio_file, "file !")
+        except IOError:
+            raise IOError("Unable to open " + gpio_file + "file !")
 
         retval = retval.rstrip('\r\n')
         return retval
@@ -76,11 +67,10 @@ def get_psu_status(self, index):
         """
         status = 0
         psu_status = self.read_psu_statuses(self.psu[index]['power'])
-        if (psu_status != 'ERR'):
-            psu_status = int(psu_status, 10)
-            # Check for PSU status
-            if (psu_status == 1):
-                    status = 1
+        psu_status = int(psu_status, 10)
+        # Check for PSU status
+        if (psu_status == 1):
+             status = 1
 
         return status
 
@@ -93,10 +83,9 @@ def get_psu_presence(self, index):
         """
         status = 0
         psu_absence = self.read_psu_statuses(self.psu[index]['abs'])
-        if (psu_absence != 'ERR'):
-            psu_absence = (int(psu_absence, 10))
-            # Check for PSU presence
-            if (psu_absence == 0):
-                    status = 1
+        psu_absence = (int(psu_absence, 10))
+        # Check for PSU presence
+        if (psu_absence == 0):
+            status = 1
 
         return status