aioble/l2cap: Use DeviceDisconnectedError directly.

L2CAPChannel.__init__ raised ValueError("Not connected") when the
connection was already disconnected.  Change this to raise
DeviceDisconnectedError directly, which is the exception callers
(e.g. l2cap_file_server example) already catch.

Also make L2CAPDisconnectedError a subclass of DeviceDisconnectedError
so that mid-operation L2CAP disconnections are caught by the same
handler.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

Author: pi-anl

micropython/bluetooth/aioble/aioble/l2cap.py

@@ -6,7 +6,7 @@
 import asyncio
 
 from .core import ble, log_error, register_irq_handler
-from .device import DeviceConnection
+from .device import DeviceConnection, DeviceDisconnectedError
 
 
 _IRQ_L2CAP_ACCEPT = const(22)
@@ -63,7 +63,7 @@ def _l2cap_shutdown():
 
 
 # The channel was disconnected during a send/recvinto/flush.
-class L2CAPDisconnectedError(Exception):
+class L2CAPDisconnectedError(DeviceDisconnectedError):
     pass
 
 
@@ -75,7 +75,7 @@ class L2CAPConnectionError(Exception):
 class L2CAPChannel:
     def __init__(self, connection):
         if not connection.is_connected():
-            raise ValueError("Not connected")
+            raise DeviceDisconnectedError
 
         if connection._l2cap_channel:
             raise ValueError("Already has channel")