[as9716-32d] Add to support lpmode for sfputil (#5171)

Implement code to set/get lpmode for as9716-32d platform

device/accton/x86_64-accton_as9716_32d-r0/plugins/sfputil.py

@@ -7,6 +7,7 @@
  import time
  import os
  import sys, getopt
+ from ctypes import create_string_buffer
  from sonic_sfp.sfputilbase import SfpUtilBase
 except ImportError as e:
  raise ImportError("%s - required module not found" % str(e))
@@ -115,10 +116,65 @@ def get_presence(self, port_num):
  return False
 
  def get_low_power_mode(self, port_num): 
- raise NotImplementedError
+ # Check for invalid port_num
+ if port_num < self.port_start or port_num > self.port_end:
+ return False
+
+ try:
+ eeprom = None
+
+ if not self.get_presence(port_num):
+ return False
+
+ eeprom = open(self.port_to_eeprom_mapping[port_num], "rb")
+ eeprom.seek(93)
+ lpmode = ord(eeprom.read(1))
+
+ if ((lpmode & 0x3) == 0x3):
+ return True # Low Power Mode if "Power override" bit is 1 and "Power set" bit is 1
+ else:
+ return False # High Power Mode if one of the following conditions is matched:
+ # 1. "Power override" bit is 0
+ # 2. "Power override" bit is 1 and "Power set" bit is 0 
+ except IOError as e:
+ print "Error: unable to open file: %s" % str(e)
+ return False
+ finally:
+ if eeprom is not None:
+ eeprom.close()
+ time.sleep(0.01)
 
  def set_low_power_mode(self, port_num, lpmode):
- raise NotImplementedError
+ # Check for invalid port_num
+ if port_num < self.port_start or port_num > self.port_end:
+ return False
+
+ try:
+ eeprom = None
+
+ if not self.get_presence(port_num):
+ return False # Port is not present, unable to set the eeprom
+
+ # Fill in write buffer
+ # 0x3:Low Power Mode. "Power override" bit is 1 and "Power set" bit is 1 
+ # 0x9:High Power Mode. "Power override" bit is 1 ,"Power set" bit is 0 and "High Power Class Enable" bit is 1 
+ regval = 0x3 if lpmode else 0x9 
+
+ buffer = create_string_buffer(1)
+ buffer[0] = chr(regval)
+
+ # Write to eeprom
+ eeprom = open(self.port_to_eeprom_mapping[port_num], "r+b")
+ eeprom.seek(93)
+ eeprom.write(buffer[0])
+ return True
+ except IOError as e:
+ print "Error: unable to open file: %s" % str(e)
+ return False
+ finally:
+ if eeprom is not None:
+ eeprom.close()
+ time.sleep(0.01)
 
  def reset(self, port_num):
  if port_num < self.port_start or port_num > self.port_end: