helloedison.c: add edison type example

This small example shows the use of mraa_get_pin and documents the owner
concept

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

diff --git a/examples/helloedison.c b/examples/helloedison.c
new file mode 100644 (file)
index 0000000..b34eb1c
--- /dev/null
+++ b/examples/helloedison.c
@@ -0,0 +1,69 @@
+/*
+ * Author: Brendan Le Foll <brendan.le.foll@intel.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.
+ */
+
+#include <stdio.h>
+#include <syslog.h>
+#include <string.h>
+#include <stdbool.h>
+//! [Interesting]
+#include "mraa.h"
+
+int
+main(int argc, char **argv)
+{
+    mraa_result_t ret = MRAA_SUCCESS;
+    mraa_platform_t platform_type = mraa_get_platform_type();
+
+    if (platform_type != MRAA_INTEL_EDISON_FAB_C) {
+        fprintf(stderr, "Error: This program can only run on an edison\n");
+        ret = MRAA_ERROR_INVALID_PLATFORM;
+        goto end;
+    }
+
+    // MRAA_INTEL_EDISON_GP182 == 0 so this will initialise pin0 on arduino
+    // which is hardware gpio 130 and not 182
+    mraa_gpio_context gpio182 = mraa_gpio_init(MRAA_INTEL_EDISON_GP182);
+    if (gpio182 == NULL) {
+        fprintf(stderr, "Error: Failed to open gpio182\n");
+        ret = MRAA_ERROR_INVALID_PLATFORM;
+        goto end;
+    }
+    mraa_gpio_dir(gpio182, MRAA_GPIO_OUT);
+
+    // we set the owner to false here, this makes sure that we do not close the
+    // gpio from sysfs in mraa_gpio_close meaning it will stay as an output and
+    // we will not always transition from 0->1 as gpio182 as output has the
+    // default position of '0'. Note that the value could change as a result of
+    // a mraa_gpio_dir however meaning we always go from 0->1 or 1->0
+    mraa_gpio_owner(gpio182, false);
+    int val = mraa_gpio_read(gpio182);
+    printf("GPIO%d (mraa pin %d) was: %d, will set to %d\n", 182, mraa_gpio_get_pin(gpio182), val, !val);
+    mraa_gpio_write(gpio182, !val);
+    mraa_gpio_close(gpio182);
+
+end:
+    mraa_deinit();
+    return ret;
+}
+//! [Interesting]