galileo: Add GPIO interrupt example

This patch introduces an example application to demonstrate how to use
GPIO driver APIs to manipulate interrupt pins.

The application uses default galileo pinmux initialization and sets
the GPIO 5 (IO2) as output pin and GPIO 6 (IO3) as interrupt. It toggles
the output pin stat at every half second in order to emulate an interrupt.
This triggers an interrupt and the application callback is called.

examples/galileo/Makefile

@@ -1,6 +1,6 @@
 TARGET=galileo
 
-KNOWN_EXAMPLES = gpio-input gpio-output i2c-LSM9DS0
+KNOWN_EXAMPLES = gpio-input gpio-output gpio-interrupt i2c-LSM9DS0
 
 ifneq ($(filter $(EXAMPLE),$(KNOWN_EXAMPLES)),)
   CONTIKI_PROJECT = $(EXAMPLE)

examples/galileo/README

@@ -31,6 +31,16 @@ pins. This application uses default galileo pinmux initialization and sets
 the GPIO 5 (IO2) as output pin and GPIO 6 (IO3) as input. It toggles the
 output pin state at every half second and checks the value on input pin.
 
+GPIO Interrupt
+==============
+
+This application shows how to use the GPIO driver APIs to manipulate interrupt
+pins. This application uses default galileo pinmux initialization and sets
+the GPIO 5 (IO2) as output pin and GPIO 6 (IO3) as interrupt. It toggles the
+output pin stat at every half second in order to emulate an interrupt. This
+triggers an interrupt and the application callback is called. You can confirm
+that though the UART output.
+
 =======
 = I2C =
 =======

examples/galileo/gpio-interrupt.c

@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2015, Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+
+#include "contiki.h"
+#include "sys/ctimer.h"
+
+#include "gpio.h"
+#include "i2c.h"
+#include "galileo-pinmux.h"
+
+#define PIN_OUTPUT 5
+#define PIN_INTR 6
+
+static struct ctimer timer;
+static struct quarkX1000_i2c_config i2c_config;
+
+PROCESS(gpio_interrupt_process, "GPIO Interrupt Process");
+AUTOSTART_PROCESSES(&gpio_interrupt_process);
+/*---------------------------------------------------------------------------*/
+static void
+timeout(void *data)
+{
+  /* emulate an interrupt */
+  quarkX1000_gpio_write(PIN_OUTPUT, 0);
+  quarkX1000_gpio_write(PIN_OUTPUT, 1);
+
+  ctimer_reset(&timer);
+}
+/*---------------------------------------------------------------------------*/
+static void
+callback(uint32_t status)
+{
+  printf("GPIO interrupt callback called, status: %d\n", status);
+}
+/*---------------------------------------------------------------------------*/
+PROCESS_THREAD(gpio_interrupt_process, ev, data)
+{
+  PROCESS_BEGIN();
+
+  i2c_config.speed = QUARKX1000_I2C_SPEED_STANDARD;
+  i2c_config.addressing_mode = QUARKX1000_I2C_ADDR_MODE_7BIT;
+
+  quarkX1000_i2c_init();
+  quarkX1000_i2c_configure(&i2c_config);
+
+  /* use default pinmux configuration */
+  galileo_pinmux_initialize();
+
+  quarkX1000_gpio_init();
+  quarkX1000_gpio_config(PIN_OUTPUT, QUARKX1000_GPIO_OUT);
+  quarkX1000_gpio_config(PIN_INTR, QUARKX1000_GPIO_INT | QUARKX1000_GPIO_ACTIVE_HIGH | QUARKX1000_GPIO_EDGE);
+
+  quarkX1000_gpio_set_callback(callback);
+
+  quarkX1000_gpio_clock_enable();
+
+  ctimer_set(&timer, CLOCK_SECOND / 2, timeout, NULL);
+
+  printf("GPIO interrupt example is running\n");
+  PROCESS_YIELD();
+
+  quarkX1000_gpio_clock_disable();
+
+  PROCESS_END();
+}