Common power consumption and supply APIs for modular chassis (#136)

sonic-platform-base: Changes to introduce APIs for modular chassis for power-consumption and supplied

HLD: sonic-net/SONiC#646

PSUd APIs for power requirement calculations

get_maximum_supplied_power() - per PSU
get_status_master_led() - get master psu led status. Class method.
set_status_master_led() - set master psu led status. Class method.

get_maximum_consumed_power(self) - per consumer API. Consumers are modules, Fans

sonic_platform_base/chassis_base.py

@@ -144,6 +144,17 @@ def get_my_slot(self):
         """
         return NotImplementedError
 
+    def is_modular_chassis(self):
+        """
+        Retrieves whether the sonic instance is part of modular chassis
+
+        Returns:
+            A bool value, should return False by default or for fixed-platforms.
+            Should return True for supervisor-cards, line-cards etc running as part
+            of modular-chassis.
+        """
+        return False
+
     ##############################################
     # Component methods
     ##############################################

sonic_platform_base/device_base.py

@@ -11,6 +11,12 @@ class DeviceBase(object):
     peripheral device
     """
 
+    # Possible status LED colors
+    STATUS_LED_COLOR_GREEN = "green"
+    STATUS_LED_COLOR_AMBER = "amber"
+    STATUS_LED_COLOR_RED = "red"
+    STATUS_LED_COLOR_OFF = "off"
+
     def get_name(self):
         """
         Retrieves the name of the device

sonic_platform_base/fan_drawer_base.py

@@ -81,3 +81,13 @@ def get_status_led(self, color):
             A string, one of the predefined STATUS_LED_COLOR_* strings above
         """
         raise NotImplementedError
+
+    def get_maximum_consumed_power(self):
+        """
+        Retrives the maximum power drawn by Fan Drawer
+
+        Returns:
+            A float, with value of the maximum consumable power of the
+            component.
+        """
+        raise NotImplementedError

sonic_platform_base/module_base.py

@@ -186,6 +186,16 @@ def set_admin_state(self, up):
         """
         raise NotImplementedError
 
+    def get_maximum_consumed_power(self):
+        """
+        Retrives the maximum power drawn by this module
+
+        Returns:
+            A float, with value of the maximum consumable power of the
+            module.
+        """
+        raise NotImplementedError
+
     ##############################################
     # Component methods
     ##############################################

sonic_platform_base/psu_base.py

@@ -15,12 +15,6 @@ class PsuBase(device_base.DeviceBase):
     # Device type definition. Note, this is a constant.
     DEVICE_TYPE = "psu"
 
-    # Possible fan status LED colors
-    STATUS_LED_COLOR_GREEN = "green"
-    STATUS_LED_COLOR_AMBER = "amber"
-    STATUS_LED_COLOR_RED = "red"
-    STATUS_LED_COLOR_OFF = "off"
-
     # List of FanBase-derived objects representing all fans
     # available on the PSU
     _fan_list = None
@@ -32,6 +26,9 @@ class PsuBase(device_base.DeviceBase):
     # PSU class
     _thermal_list = []
 
+    # Status of Master LED
+    psu_master_led_color = device_base.DeviceBase.STATUS_LED_COLOR_OFF
+
     def __init__(self):
         self._fan_list = []
 
@@ -219,3 +216,35 @@ def get_voltage_low_threshold(self):
             e.g. 12.1 
         """
         raise NotImplementedError
+
+    def get_maximum_supplied_power(self):
+        """
+        Retrieves the maximum supplied power by PSU
+
+        Returns:
+            A float number, the maximum power output in Watts.
+            e.g. 1200.1
+        """
+        raise NotImplementedError
+
+    @classmethod
+    def get_status_master_led(cls):
+        """
+        Gets the state of the Master status LED for a given device-type
+
+        Returns:
+            A string, one of the predefined STATUS_LED_COLOR_* strings.
+        """
+        return cls.psu_master_led_color
+
+    @classmethod
+    def set_status_master_led(cls, color):
+        """
+        Gets the state of the Master status LED for a given device-type
+
+        Returns:
+            bool: True if status LED state is set successfully, False if
+                  not
+        """
+        cls.psu_master_led_color = color
+        return True