nmea_gps: renamed vk2828u7 to nmea_gps

This driver will serve as a generic module for grabbing NMEA data from
various GPS devices via a serial interface.  ublox6 will also be
removed in favor of using this driver going forward.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

src/nmea_gps/nmea_gps.c

@@ -0,0 +1,151 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2016 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 <string.h>
+#include <assert.h>
+
+#include "nmea_gps.h"
+
+#include "upm_utilities.h"
+
+nmea_gps_context nmea_gps_init(unsigned int uart, unsigned int baudrate,
+                               int enable_pin)
+{
+  nmea_gps_context dev =
+    (nmea_gps_context)malloc(sizeof(struct _nmea_gps_context));
+
+  if (!dev)
+    return NULL;
+
+  // zero out context
+  memset((void *)dev, 0, sizeof(struct _nmea_gps_context));
+  
+  dev->uart = NULL;
+  dev->gpio_en = NULL;
+
+  // initialize the MRAA contexts
+
+  // uart, default should be 8N1
+  if (!(dev->uart = mraa_uart_init(uart)))
+    {
+      printf("%s: mraa_uart_init() failed.\n", __FUNCTION__);
+      nmea_gps_close(dev);
+      return NULL;
+    }
+
+  if (nmea_gps_set_baudrate(dev, baudrate))
+    {
+      printf("%s: nmea_gps_set_baudrate() failed.\n", __FUNCTION__);
+      nmea_gps_close(dev);
+      return NULL;
+    }      
+
+  mraa_uart_set_flowcontrol(dev->uart, false, false);
+
+  // now the gpio_en, if enabled
+  if (enable_pin >= 0)
+    {
+      if (!(dev->gpio_en = mraa_gpio_init(enable_pin)))
+        {
+          printf("%s: mraa_gpio_init() failed.\n", __FUNCTION__);
+          nmea_gps_close(dev);
+          return NULL;
+        }
+
+      mraa_gpio_dir(dev->gpio_en, MRAA_GPIO_OUT);
+
+      // wake up
+      nmea_gps_enable(dev, true);
+    }
+
+  return dev;
+}
+
+void nmea_gps_close(nmea_gps_context dev)
+{
+  assert(dev != NULL);
+
+  // sleepy-time
+  nmea_gps_enable(dev, false);
+
+  if (dev->uart)
+    mraa_uart_stop(dev->uart);
+  if (dev->gpio_en)
+    mraa_gpio_close(dev->gpio_en);
+
+  free(dev);
+}
+
+upm_result_t nmea_gps_enable(const nmea_gps_context dev, bool enable)
+{
+  assert(dev != NULL);
+
+  if (!dev->gpio_en)
+    return UPM_ERROR_NO_RESOURCES;
+
+  if (enable)
+    mraa_gpio_write(dev->gpio_en, 1);
+  else
+    mraa_gpio_write(dev->gpio_en, 0);
+
+  return UPM_SUCCESS;
+}
+
+int nmea_gps_read(const nmea_gps_context dev, char *buffer, size_t len)
+{
+  assert(dev != NULL);
+
+  return mraa_uart_read(dev->uart, buffer, len);
+}
+
+int nmea_gps_write(const nmea_gps_context dev, char *buffer, size_t len)
+{
+  assert(dev != NULL);
+
+  return mraa_uart_write(dev->uart, buffer, len);
+}
+
+bool nmea_gps_data_available(const nmea_gps_context dev, unsigned int millis)
+{
+  assert(dev != NULL);
+
+  if (mraa_uart_data_available(dev->uart, millis))
+    return true;
+  else
+    return false;
+}
+
+upm_result_t nmea_gps_set_baudrate(const nmea_gps_context dev,
+                                   unsigned int baudrate)
+{
+  assert(dev != NULL);
+
+  if (mraa_uart_set_baudrate(dev->uart, baudrate))
+    {
+      printf("%s: mraa_uart_set_baudrate() failed.\n", __FUNCTION__);
+      return UPM_ERROR_OPERATION_FAILED;
+    }      
+
+  return UPM_SUCCESS;
+}