Add --verbose option.

src/nfc/__main__.py

@@ -25,6 +25,7 @@
 
 import os
 import errno
+import logging
 import platform
 import argparse
 import subprocess
@@ -46,6 +47,11 @@ def main(args):
           (nfc.__version__, platform.python_version(), platform.platform()))
     print("I'm now searching your system for contactless devices")
 
+    logging.basicConfig()
+    log_levels = (logging.WARN, logging.INFO, logging.DEBUG, logging.DEBUG-1)
+    log_level = log_levels[min(args.verbose, len(log_levels) - 1)]
+    logging.getLogger('nfc').setLevel(log_level)
+
     found = 0
     for vid, pid, bus, dev in nfc.clf.transport.USB.find("usb"):
         if (vid, pid) in nfc.clf.device.usb_device_map:
@@ -201,4 +207,8 @@ def usb_device_found_is_busy(bus, dev, vid, pid, path):
     "--search-tty", action="store_true",
     help="do also search for serial devices on linux")
 
+parser.add_argument(
+    "--verbose", "-v", action="count", default=0,
+    help="be verbose. Multiple -v options increase the verbosity.")
+
 main(parser.parse_args())