ds2413: Initial implementation

This adds initial support for the DS2413 Dual Channel Addressable
Switch.  This is a Dallas Semiconductor 1-wire compliant device
providing access to 2 open-drain GPIOs.

https://learn.adafruit.com/adafruit-1-wire-gpio-breakout-ds2413/overview

This driver requires One-Wire over UART support in MRAA (PR #415)
which is not yet merged.

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

examples/javascript/ds2413.js

@@ -0,0 +1,55 @@
+/*jslint node:true, vars:true, bitwise:true, unparam:true */
+/*jshint unused:true */
+
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2015 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.
+ */
+
+
+var sensorObj = require('jsupm_ds2413');
+
+
+/************** Main code **************/
+// Instantiate a DS2413 Module on a Dallas 1-wire bus connected to UART 0
+var sensor = new sensorObj.DS2413(0);
+
+// find all of the DS2413 devices present on the bus
+sensor.init();
+
+// how many devices were found?
+console.log("Found", sensor.devicesFound(), "device(s)");
+
+// read the gpio and latch values from the first device
+// the lower 4 bits are of the form:
+// <gpioB latch> <gpioB value> <gpioA latch> <gpioA value>
+console.log("GPIO device 0 values:", sensor.readGpios(0));
+
+// set the gpio latch values of the first device
+console.log("Setting GPIO latches to on");;
+sensor.writeGpios(0, 0x03);
+
+sensor = null;
+sensorObj.cleanUp();
+sensorObj = null;
+console.log("Exiting...");
+process.exit(0);