vdiv: Added vdiv C source.

Multiple changes related to building the vdiv c source w/c example.

    * Renamed GroveVdiv to vdiv (all cases) throughout source, examples,
    directory names, and documentation.

    * Added C source.

    * Tested C sensor code on edison

    * Updated CMakeLists.txt for examples-c to build from
    <sensorname>-c.  This was a small change to get c examples to build
    for sensors in which the C++ does NOT wrap the C.

    * Added C example for vdiv.

Signed-off-by: Noel Eck <noel.eck@intel.com>

examples/c/CMakeLists.txt

@@ -38,7 +38,7 @@ macro(add_custom_example example_bin example_src example_module_list)
       if (${module} STREQUAL "lcd")
         set(module "i2clcd")
       endif()
-      target_link_libraries (${example_bin} ${module})
+      target_link_libraries (${example_bin} ${module}-c)
     endforeach()
   else()
    MESSAGE(INFO " Ignored ${example_bin}")
@@ -94,6 +94,7 @@ add_example (urm37)
 add_example (urm37-uart)
 add_example (hka5)
 add_example (dfrorp)
+add_example (vdiv)
 
 # Custom examples
 add_custom_example (nmea_gps_i2c-example-c nmea_gps_i2c.c nmea_gps)

examples/c/vdiv.c

@@ -0,0 +1,74 @@
+/*
+ * 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.
+ */
+
+#include <unistd.h>
+#include <signal.h>
+
+#include "vdiv.h"
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+    if (signo == SIGINT)
+        shouldRun = false;
+}
+
+int main()
+{
+    signal(SIGINT, sig_handler);
+
+    //! [Interesting]
+
+    // Instantiate a sensor on analog pin A0
+    vdiv_context sensor = vdiv_init(0, 5);
+
+    if (!sensor)
+    {
+        printf("vdiv_init() failed.\n");
+        return(1);
+    }
+
+    // Every half a second, sample the sensor output
+    while (shouldRun)
+    {
+        float raw_volts = 0.0, computed_volts = 0.0;
+
+        vdiv_get_raw_volts(sensor, &raw_volts);
+        vdiv_get_computed_volts(sensor, &computed_volts);
+
+        printf("Divide SW: %d ADC voltage: %0.03f Sensor voltage: %0.03f\n",
+                vdiv_get_divsw(sensor), raw_volts, computed_volts);
+
+        usleep(500000);
+    }
+
+    //! [Interesting]
+
+    printf("Exiting\n");
+
+    vdiv_close(sensor);
+
+    return 0;
+}