hka5: Initial implementation

This module implements support for the DFRobot Laser PM2.5 Sensor.  It
connects to a UART at 9600 baud.  This is the only baud rate
supported.  It optionally supports Reset and Set/Sleep gpios as well.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/python/hka5.py

@@ -0,0 +1,62 @@
+#!/usr/bin/python
+# Author: Jon Trulson <jtrulson@ics.com>
+# Copyright (c) 2016 Intel Corporation.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+import time, sys, signal, atexit
+import pyupm_hka5 as sensorObj
+
+# Instantiate a HKA5 sensor on uart 0.  We don't use the set or
+# reset pins, so we pass -1 for them.
+sensor = sensorObj.HKA5(0, -1, -1)
+
+## Exit handlers ##
+# This function stops python from printing a stacktrace when you hit control-C
+def SIGINTHandler(signum, frame):
+	raise SystemExit
+
+# This function lets you run code on exit
+def exitHandler():
+	print "Exiting"
+	sys.exit(0)
+
+# Register exit handlers
+atexit.register(exitHandler)
+signal.signal(signal.SIGINT, SIGINTHandler)
+
+# update once every 2 seconds and output data
+while (True):
+        sensor.update()
+
+        print "PM 1  :",
+        print sensor.getPM1(),
+        print " ug/m3"
+
+        print "PM 2.5:",
+        print sensor.getPM2_5(),
+        print " ug/m3"
+
+        print "PM 10 :",
+        print sensor.getPM10(),
+        print " ug/m3"
+
+        print
+        time.sleep(2)