lcdks: renamed from sainsmartks, added backlight support

The sainsmartks driver has been reimplemented in it's own, new C/C++
library: lcdks (LCD Keypad Shield).

In addition, support for an optional backlight GPIO was added.

This was tested with the SainsmartKS and DFRobot LCD Keypad Shields.

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

examples/python/lcdks.py

@@ -0,0 +1,63 @@
+#!/usr/bin/python
+# Author: Jon Trulson <jtrulson@ics.com>
+# Copyright (c) 2017 Intel Corporation.
+#
+# The MIT License
+#
+# 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.
+
+from __future__ import print_function
+import time, sys, signal, atexit
+from upm import pyupm_lcdks as lcdksObj
+
+def main():
+    ## Exit handlers ##
+    # This 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)
+
+    # Instantiate a LCDKS (LCD Keypad Shield) using default pins
+
+    # NOTE: The default pins do not include support for a gpio
+    # controlled backlight.  If you need one, you will need to specify
+    # all neccessary pins to the constructor.
+    lcd = lcdksObj.LCDKS()
+
+    lcd.setCursor(0,0)
+    lcd.write("LCDKS driver")
+    lcd.setCursor(1,2)
+    lcd.write("Hello World")
+
+    # output current key value every second.
+    while(1):
+        print("Button value: ", lcd.getKeyValue())
+        time.sleep(1)
+
+if __name__ == '__main__':
+    main()