ttbl.device_mapper: make ttys_find_by_spec() find TTYs without USB in…

…terface

When using ttbl.device_mapper.ttys_find_by_spec() to find TTYs
associated to a USB device, we usually had to also specify a USB
interface by appending #1.0 (the interface number), like:

>>> device_spec = "usb,#123456,##:1.0"

Which would map to /sys/devices/PATH/usbN/.../N-1.3/N-1.3:1.0 and find
ttys under ttyUSBm or tty/ttyACMm using tty* or tty/tty*.

In the case where the device has only one interface (and thus exposes
one serial port), this is overkill and adds more unneeded
verbosity. We want to be able to do just:

>>> device_spec = "usb,#123456"

So make the globs that tty_find_by_spec() be able to dig deeper into
the device structure, so it will find the subdirectories representing
the single TTY without having to specify a USB interface.

The extra globs find /sys/devices/PATH/usbN/.../N-1.3/N-1.3:1.0/ttyUSB
or /sys/devices/PATH/usbN/.../N-1.3/N-1.3:1.0/tty/ttyACM* since it
adds an extra */ to catch the interface directories hanging under the
main USB device directory.

Like this, devices which expose multiple serial ports on different USB
interfaces still can support them by specifying the interface, eg:

>>> device_spec = "usb,#123456,#:1.0"
>>> device_spec = "usb,#123456,#:2.0"

ttbd/ttbl/__init__.py

@@ -1,4 +1,4 @@
-#! /usr/bin/python3
+#! /usr/bin/env python3
 #
 # Copyright (c) 2017 Intel Corporation
 #
@@ -3049,7 +3049,15 @@ def devices_find_by_spec(self, spec: str = None, origin: str = None):
  spec, origin, " ".join(devicel))
  return devicel
 
- sysfs_tty_globs = [ "tty*", "tty/tty*" ]
+ sysfs_tty_globs = [
+ # this catches when a tty device is in the top level, such as
+ # USB devices specified just a a serial number; if a USB
+ # device specifies a single serial port, this makes it work
+ "*/tty*", "*/tty/tty*",
+ # this catches a tty device that is a subdevice (eg, in a USB
+ # device interface)
+ "tty*", "tty/tty*"
+ ]
 
  def ttys_find_by_spec(self):
  """