galileo: Add GPIO input example

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

The 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.

examples/galileo/Makefile

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

examples/galileo/README

@@ -23,6 +23,14 @@ state at every half second.
 For a visual effect, you should wire shield pin IO1 to a led in a protoboard.
 Once the application is running, you should see a blinking LED.
 
+GPIO Input
+==========
+
+This application shows how to use the GPIO driver APIs to manipulate input
+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.
+
 =======
 = I2C =
 =======

examples/galileo/gpio-input.c

@@ -0,0 +1,96 @@
+/*
+ * 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 "galileo-pinmux.h"
+#include "gpio.h"
+#include "i2c.h"
+
+#define PIN_OUTPUT 5
+#define PIN_INPUT 6
+
+static uint32_t value;
+static struct ctimer timer;
+static struct quarkX1000_i2c_config i2c_config;
+
+PROCESS(gpio_input_process, "GPIO Input Process");
+AUTOSTART_PROCESSES(&gpio_input_process);
+/*---------------------------------------------------------------------------*/
+static void
+timeout(void *data)
+{
+  uint8_t value_in;
+
+  /* toggle pin state */
+  value = !value;
+  quarkX1000_gpio_write(PIN_OUTPUT, value);
+
+  quarkX1000_gpio_read(PIN_INPUT, &value_in);
+
+  if (value == value_in)
+    printf("GPIO pin value match!\n");
+  else
+    printf("GPIO pin value DOESN'T match!\n");
+
+  ctimer_reset(&timer);
+}
+/*---------------------------------------------------------------------------*/
+PROCESS_THREAD(gpio_input_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_INPUT, QUARKX1000_GPIO_IN);
+
+  quarkX1000_gpio_clock_enable();
+
+  ctimer_set(&timer, CLOCK_SECOND / 2, timeout, NULL);
+
+  printf("GPIO input example is running\n");
+  PROCESS_YIELD();
+
+  quarkX1000_gpio_clock_disable();
+
+  PROCESS_END();
+}