speaker: C port, C++ wraps C

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

examples/c/CMakeLists.txt

@@ -143,6 +143,7 @@ add_example (ecezo)
 add_example (mb704x)
 add_example (mcp2515)
 add_example (max30100)
+add_example (speaker)
 
 # Custom examples
 add_custom_example (nmea_gps_i2c-example-c nmea_gps_i2c.c nmea_gps)

examples/c/speaker.c

@@ -0,0 +1,55 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 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 <stdio.h>
+#include "speaker.h"
+
+int main ()
+{
+//! [Interesting]
+
+    // Instantiate a Speaker on digital pin D2
+    speaker_context speaker = speaker_init(2);
+
+    if (!speaker)
+    {
+        printf("speaker_init() failed\n");
+        return 1;
+    }
+
+    // Play all 7 of the lowest notes
+    speaker_play_all(speaker);
+
+    // Play a medium C-sharp
+    speaker_play_sound(speaker, 'c', true, "med");
+
+    printf("Exiting\n");
+
+    speaker_close(speaker);
+
+//! [Interesting]
+
+    return 0;
+}