pybricksdev.usb: add Pybricks USB device class/subclass/protocol

This adds constants for the Pybricks USB device class, subclass and
protocol. These are used to identify hubs running the Pybricks firmware
when connected via USB.

The `usb` command of the CLI is modified to only accept Pybricks hubs
now. If we still want to support running programs on hubs running
official LEGO firmware, we can add that back with a different command
name.

pybricksdev/cli/__init__.py

@@ -20,6 +20,12 @@
 
 from .. import __name__ as MODULE_NAME
 from .. import __version__ as MODULE_VERSION
+from ..usb import (
+    LEGO_USB_VID,
+    PYBRICKS_USB_DEVICE_CLASS,
+    PYBRICKS_USB_DEVICE_PROTOCOL,
+    PYBRICKS_USB_DEVICE_SUBCLASS,
+)
 
 PROG_NAME = (
     f"{path.basename(sys.executable)} -m {MODULE_NAME}"
@@ -171,11 +177,11 @@ def add_parser(self, subparsers: argparse._SubParsersAction):
             )
 
     async def run(self, args: argparse.Namespace):
+        from usb.core import find as find_usb
+
         from ..ble import find_device as find_ble
         from ..connections.ev3dev import EV3Connection
-        from ..connections.lego import REPLHub
         from ..connections.pybricks import PybricksHubBLE, PybricksHubUSB
-        from usb.core import find as find_usb
 
         # Pick the right connection
         if args.conntype == "ssh":
@@ -194,12 +200,17 @@ async def run(self, args: argparse.Namespace):
             hub = PybricksHubBLE(device_or_address)
 
         elif args.conntype == "usb":
-            device_or_address = find_usb(idVendor=0x0483, idProduct=0x5740)
+            usb_device = find_usb(
+                idVendor=LEGO_USB_VID,
+                bDeviceClass=PYBRICKS_USB_DEVICE_CLASS,
+                bDeviceSubClass=PYBRICKS_USB_DEVICE_SUBCLASS,
+                bDeviceProtocol=PYBRICKS_USB_DEVICE_PROTOCOL,
+            )
+            if usb_device is None:
+                print("No Pybricks USB device found.", file=sys.stderr)
+                exit(1)
 
-            if device_or_address is not None and device_or_address.product == "Pybricks Hub":
-                hub = PybricksHubUSB(device_or_address)
-            else:
-                hub = REPLHub()
+            hub = PybricksHubUSB(usb_device)
         else:
             raise ValueError(f"Unknown connection type: {args.conntype}")
 

pybricksdev/usb/__init__.py

@@ -21,3 +21,8 @@ class LegoUsbPid(_enum.IntEnum):
     SPIKE_ESSENTIAL = 0x000D
     ROBOT_INVENTOR = 0x0010
     ROBOT_INVENTOR_DFU = 0x0011
+
+
+PYBRICKS_USB_DEVICE_CLASS = 0xFF
+PYBRICKS_USB_DEVICE_SUBCLASS = 0xC5
+PYBRICKS_USB_DEVICE_PROTOCOL = 0xF5