[device]: add minigraph and LED support for Arista 7050 QX32S (#773)

device/arista/x86_64-arista_7050_qx32s/plugins/led_control.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python
+#
+# led_control.py
+# 
+# Platform-specific LED control functionality for SONiC
+#
+
+try:
+    from sonic_led.led_control_base import LedControlBase
+except ImportError, e:
+    raise ImportError (str(e) + " - required module not found")
+
+
+class LedControl(LedControlBase):
+    """Platform specific LED control class"""
+
+    SONIC_PORT_NAME_PREFIX = "Ethernet"
+
+    LED_SYSFS_PATH_BREAKOUT_CAPABLE = "/sys/class/leds/qsfp{0}_{1}/brightness"
+    LED_SYSFS_PATH_NO_BREAKOUT = "/sys/class/leds/qsfp{0}/brightness"
+
+    QSFP_BREAKOUT_START_IDX = 1
+    QSFP_BREAKOUT_END_IDX = 24
+    QSFP_NO_BREAKOUT_START_IDX = 25
+    QSFP_NO_BREAKOUT_END_IDX = 32
+
+    LED_QSFP_OFFSET = 4
+
+    LED_COLOR_OFF = 0
+    LED_COLOR_GREEN = 1
+    LED_COLOR_YELLOW = 2
+
+    # Helper method to map SONiC port name to Arista QSFP index
+    def _port_name_to_qsfp_index(self, port_name):
+        # Strip "Ethernet" off port name
+        if not port_name.startswith(self.SONIC_PORT_NAME_PREFIX):
+            return -1
+
+        sonic_port_num = int(port_name[len(self.SONIC_PORT_NAME_PREFIX):])
+
+        # SONiC port nums are 0-based and increment by 4
+        # Arista QSFP indices are 1-based and increment by 1
+        return ((sonic_port_num/4) + 1)
+
+    # Concrete implementation of port_link_state_change() method
+    def port_link_state_change(self, port, state):
+        qsfp_index = self._port_name_to_qsfp_index(port)
+        
+        # Ignore invalid QSFP indices
+        if qsfp_index <= 0:
+            return
+
+        # QSFP indices 1-24 are breakout-capable and have four LEDs, and each LED indicate one lane.
+        # whereas indices 25-32 are not breakout-capable, and only have one
+        if qsfp_index <= self.QSFP_BREAKOUT_END_IDX:
+            # assuming 40G, then we need to control four lanes
+            led_sysfs_paths = [ self.LED_SYSFS_PATH_BREAKOUT_CAPABLE.format(qsfp_index + self.LED_QSFP_OFFSET, i) for i in range(1, 5) ]
+        else:
+            led_sysfs_paths = [ self.LED_SYSFS_PATH_NO_BREAKOUT.format(qsfp_index + self.LED_QSFP_OFFSET) ]
+
+        for led_sysfs_path in led_sysfs_paths:
+            led_file = open(led_sysfs_path, "w")
+
+            if state == "up":
+                led_file.write("%d" % self.LED_COLOR_GREEN)
+            else:
+                led_file.write("%d" % self.LED_COLOR_OFF)
+
+            led_file.close()
+
+    # Constructor
+    def __init__(self):
+        # Initialize: Turn all front panel QSFP LEDs off
+        for qsfp_index in range(self.QSFP_BREAKOUT_START_IDX, self.QSFP_BREAKOUT_END_IDX + 1):
+            for lane in range(1, 5):
+                led_sysfs_path = self.LED_SYSFS_PATH_BREAKOUT_CAPABLE.format(qsfp_index + self.LED_QSFP_OFFSET, lane)
+                with open(led_sysfs_path, 'w') as led_file:
+                    led_file.write("%d" % self.LED_COLOR_OFF)
+
+        for qsfp_index in range(self.QSFP_NO_BREAKOUT_START_IDX, self.QSFP_NO_BREAKOUT_END_IDX + 1):
+            led_sysfs_path = self.LED_SYSFS_PATH_NO_BREAKOUT.format(qsfp_index + self.LED_QSFP_OFFSET)
+            with open(led_sysfs_path, 'w') as led_file:
+                led_file.write("%d" % self.LED_COLOR_OFF)
+