Add a small LED interface and demo app.

app/dartino/leds.c

Index: app/dartino/leds.c
diff --git a/app/dartino/leds.c b/app/dartino/leds.c
new file mode 100644
index 0000000000000000000000000000000000000000..832bc2792712ec12362d7b97d151a7fe49701a60
--- /dev/null
+++ b/app/dartino/leds.c
@@ -0,0 +1,37 @@
+
+// Copyright (c) 2015, the Dartino project authors. Please see the AUTHORS file

[Søren Gjesse, 2016/02/09 09:16:01]

2016

+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE.md file.
+
+#include <kernel/port.h>
+
+#if defined(TARGET_DARTUINOP0)
+#include <dev/gpio.h>
+#include <target/gpioconfig.h>
+
+int change_led_status(int led, int on) {
+  int gpioid;
+  switch (led) {
+    case 0:
+      gpioid = GPIO_LED108;
+      break;
+    case 1:
+      gpioid = GPIO_LED109;
+      break;
+    case 2:
+      gpioid = GPIO_LED110;
+      break;
+    case 3:
+      gpioid = GPIO_LED111;
+      break;
+    default:
+      return 0;
+  }
+  gpio_set(gpioid, on);
+  return 1;
+}
+#else

[Søren Gjesse, 2016/02/09 09:16:01]

Can't we just say #error here?

[herhut, 2016/02/09 10:10:15]

No, cause then it won't build on qemu, which is used for general testing of
other stuff. We do not have (and probably don't need) LED emulation on QEmu.

I have changed it into a lookup function for the GPIO mapping, which on qemu
always returns -1 (meaning not present).

+int change_led_status(int led, bool on) {
+  return 0;
+}
+#endif