support self.pin during migration (#180)

re add the pin member with details for the I2C direct control of the port expanders to allow easier migration.

modules/tildagon/pins.py

@@ -33,10 +33,44 @@
     "6_LS_E": (0, 15),
 }
 
+HEXPANSION_I2C = {
+    "1_LS_A": (0x5A, 0, 1 << 3),
+    "1_LS_B": (0x5A, 1, 1 << 0),
+    "1_LS_C": (0x5A, 1, 1 << 1),
+    "1_LS_D": (0x5A, 1, 1 << 2),
+    "1_LS_E": (0x5A, 1, 1 << 3),
+    "2_LS_A": (0x5A, 0, 1 << 0),
+    "2_LS_B": (0x5A, 0, 1 << 1),
+    "2_LS_C": (0x59, 1, 1 << 5),
+    "2_LS_D": (0x59, 1, 1 << 6),
+    "2_LS_E": (0x59, 1, 1 << 7),
+    "3_LS_A": (0x59, 0, 1 << 4),
+    "3_LS_B": (0x59, 0, 1 << 5),
+    "3_LS_C": (0x59, 0, 1 << 6),
+    "3_LS_D": (0x59, 0, 1 << 7),
+    "3_LS_E": (0x59, 1, 1 << 4),
+    "4_LS_A": (0x58, 1, 1 << 0),
+    "4_LS_B": (0x58, 1, 1 << 1),
+    "4_LS_C": (0x58, 1, 1 << 2),
+    "4_LS_D": (0x58, 1, 1 << 3),
+    "4_LS_E": (0x58, 0, 1 << 0),
+    "5_LS_A": (0x58, 0, 1 << 2),
+    "5_LS_B": (0x58, 0, 1 << 3),
+    "5_LS_C": (0x58, 0, 1 << 4),
+    "5_LS_D": (0x58, 0, 1 << 5),
+    "5_LS_E": (0x58, 1, 1 << 6),
+    "6_LS_A": (0x58, 0, 1 << 7),
+    "6_LS_B": (0x58, 1, 1 << 4),
+    "6_LS_C": (0x58, 1, 1 << 5),
+    "6_LS_D": (0x58, 1, 1 << 6),
+    "6_LS_E": (0x58, 1, 1 << 7),
+}
+
 
 class Pin(ePin):
     def __init__(self, pin_name, mode=None):
         self.name = pin_name
+        self.pin = HEXPANSION_I2C[pin_name]
         super().__init__(HEXPANSION_GPIOS[pin_name], mode)
 
     def __repr__(self):