tools/mpremote: Add support for rfc2217, serial over TCP.

Signed-off-by: Jos Verlinde <jos_verlinde@hotmail.com>

docs/reference/mpremote.rst

@@ -100,6 +100,8 @@ The full list of supported commands are:
     command output)
   - ``port:<path>``: connect to the device with the given path (the first column
     from the ``connect list`` command output
+  - ``rfc2217://<host>:<port>``: connect to the device using serial over TCP
+    (e.g. a networked serial port based on RFC2217)
   - any valid device name/path, to connect to that device
 
   **Note:** Instead of using the ``connect`` command, there are several
@@ -109,7 +111,7 @@ The full list of supported commands are:
 
   **Note:** The ``auto`` option will only detect USB serial ports, i.e. a serial
   port that has an associated USB VID/PID (i.e. CDC/ACM or FTDI-style
-  devices). Other types of serial ports
+  devices). Other types of serial ports will not be auto-detected.
 
 .. _mpremote_command_disconnect:
 

tools/mpremote/mpremote/transport_serial.py

@@ -76,7 +76,9 @@ class SerialTransport(Transport):
         delayed = False
         for attempt in range(wait + 1):
             try:
-                if os.name == "nt":
+                if device.startswith("rfc2217://"):
+                    self.serial = serial.serial_for_url(device, **serial_kwargs)
+                elif os.name == "nt":
                     self.serial = serial.Serial(**serial_kwargs)
                     self.serial.port = device
                     portinfo = list(serial.tools.list_ports.grep(device))  # type: ignore