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/c/CMakeLists.txt

@@ -152,6 +152,7 @@ add_example (nunchuck)
 add_example (bno055)
 add_example (bmp280)
 add_example (abpdrrt005pg2a5)
+add_example (lcdks)
 
 # Custom examples
 add_custom_example (nmea_gps_i2c-example-c nmea_gps_i2c.c nmea_gps)

examples/c/lcdks.c

@@ -0,0 +1,89 @@
+/*
+ * 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.
+ */
+
+#include <unistd.h>
+#include <signal.h>
+#include <stdio.h>
+
+#include "upm_utilities.h"
+#include "lcdks.h"
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+    if (signo == SIGINT)
+        shouldRun = false;
+}
+
+
+int main(int argc, char **argv)
+{
+    signal(SIGINT, sig_handler);
+
+//! [Interesting]
+
+    // Instantiate a LCDKS (LCD Keypad Shield) using default pins
+
+    // LCD connection:
+    // LCD RS pin to digital pin 8
+    // LCD Enable pin to digital pin 9
+    // LCD D4 pin to digital pin 4
+    // LCD D5 pin to digital pin 5
+    // LCD D6 pin to digital pin 6
+    // LCD D7 pin to digital pin 7
+    // Keypad analog pin 0
+    // Backlight GPIO -1 (disabled)
+
+    // NOTE: The default pins do not include support for a gpio
+    // controlled backlight.  If you need one, specify the correct pin
+    // as the last argument instead of -1.
+    lcdks_context lcd = lcdks_init(8, 9, 4, 5, 6, 7, 0, -1);
+
+    if (!lcd)
+    {
+        printf("lcdks_init() failed.\n");
+        return 1;
+    }
+
+
+    lcdks_set_cursor(lcd, 0, 0);
+    lcdks_write(lcd, "LCDKS driver", 12);
+    lcdks_set_cursor(lcd, 1, 2);
+    lcdks_write(lcd, "Hello World", 11);
+
+    // output current key value every second.
+    while (shouldRun)
+    {
+        printf("Button value: %f\n", lcdks_get_key_value(lcd));
+        upm_delay(1);
+    }
+
+    lcdks_close(lcd);
+
+//! [Interesting]
+    return 0;
+}