initial import

bumble/transport/serial.py

@@ -0,0 +1,72 @@
+# Copyright 2021-2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import asyncio
+import logging
+import serial_asyncio
+
+from .common import Transport, StreamPacketSource, StreamPacketSink
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+async def open_serial_transport(spec):
+    '''
+    Open a serial port transport.
+    The parameter string has this syntax:
+    <device-path>[,<speed>][,rtscts][,dsrdtr]
+    When <speed> is omitted, the default value of 1000000 is used
+    When "rtscts" is specified, RTS/CTS hardware flow control is enabled
+    When "dsrdtr" is specified, DSR/DTR hardware flow control is enabled
+
+    Examples:
+    /dev/tty.usbmodem0006839912172
+    /dev/tty.usbmodem0006839912172,1000000
+    /dev/tty.usbmodem0006839912172,rtscts
+    '''
+
+    speed = 1000000
+    rtscts = False
+    dsrdtr = False
+    if ',' in spec:
+        parts = spec.split(',')
+        device = parts[0]
+        for part in parts[1:]:
+            if part == 'rtscts':
+                rtscts = True
+            elif part == 'dsrdtr':
+                dsrdtr = True
+            elif part.isnumeric():
+                speed = int(part)
+    else:
+        device = spec
+    serial_transport, packet_source = await serial_asyncio.create_serial_connection(
+        asyncio.get_running_loop(),
+        lambda: StreamPacketSource(),
+        device,
+        baudrate=speed,
+        rtscts=rtscts,
+        dsrdtr=dsrdtr
+    )
+    packet_sink = StreamPacketSink(serial_transport)
+
+    return Transport(packet_source, packet_sink)
+