Fix USB connection to CF (#312)

Adding a USB reset seems to fix the USB connection to the Crazyflie when
trying to connect multiple times.

Fixes #264

Author: ataffanel

cflib/crtp/usbdriver.py

@@ -70,17 +70,16 @@ def connect(self, uri, link_quality_callback, link_error_callback):
         """
 
         # check if the URI is a radio URI
-        if not re.search('^usb://', uri):
+        uri_data = re.search('^usb://([0-9]+)$',
+                             uri)
+        if not uri_data:
             raise WrongUriType('Not a radio URI')
 
         # Open the USB dongle
         if not re.search('^usb://([0-9]+)$',
                          uri):
             raise WrongUriType('Wrong radio URI format!')
 
-        uri_data = re.search('^usb://([0-9]+)$',
-                             uri)
-
         self.uri = uri
 
         if self.cfusb is None:

cflib/drivers/cfusb.py

@@ -27,6 +27,7 @@
 """
 import logging
 import os
+import platform
 
 import libusb_package
 import usb
@@ -90,6 +91,9 @@ def __init__(self, device=None, devid=0):
                 self.dev = None
 
         if self.dev:
+            if platform.system() == 'Linux':
+                self.dev.reset()
+
             self.dev.set_configuration(1)
             self.handle = self.dev
             self.version = float(
@@ -118,7 +122,7 @@ def scan(self):
             return [('usb://0', '')]
         return []
 
-    def set_crtp_to_usb(self, crtp_to_usb):
+    def set_crtp_to_usb(self, crtp_to_usb: bool):
         if crtp_to_usb:
             _send_vendor_setup(self.handle, 0x01, 0x01, 1, ())
         else: