mb704x: Initial implementation; C; FTI; C++ wraps C

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

src/mb704x/mb704x.c

@@ -0,0 +1,115 @@
+/*
+ * 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 <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include <upm_utilities.h>
+
+#include "mb704x.h"
+
+// The delay to wait (in ms) for a ranging command to complete before
+// requesting the range data.
+#define MB704X_RANGE_DELAY     (100)
+
+// range command
+#define MB704X_CMD_RANGE       (81)
+
+mb704x_context mb704x_init(unsigned int bus, int addr)
+{
+    // make sure MRAA is initialized
+    int mraa_rv;
+    if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
+    {
+        printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
+        return NULL;
+    }
+
+    mb704x_context dev =
+        (mb704x_context)malloc(sizeof(struct _mb704x_context));
+
+    if (!dev)
+        return NULL;
+
+    // zero out context
+    memset((void *)dev, 0, sizeof(struct _mb704x_context));
+
+    // initialize the MRAA contexts
+
+    if (!(dev->i2c = mraa_i2c_init(bus)))
+    {
+        printf("%s: mraa_i2c_init() failed.\n", __FUNCTION__);
+        mb704x_close(dev);
+        return NULL;
+    }
+
+    if (mraa_i2c_address(dev->i2c, (uint8_t)addr))
+    {
+        printf("%s: mraa_i2c_address() failed.\n", __FUNCTION__);
+        mb704x_close(dev);
+        return NULL;
+    }
+
+    // max power up delay
+    upm_delay_ms(135);
+
+    return dev;
+}
+
+void mb704x_close(mb704x_context dev)
+{
+    assert(dev != NULL);
+
+    if (dev->i2c)
+        mraa_i2c_stop(dev->i2c);
+
+    free(dev);
+}
+
+int mb704x_get_range(const mb704x_context dev)
+{
+    assert(dev != NULL);
+
+    // first, send the range command.
+    uint8_t cmd = MB704X_CMD_RANGE;
+    if (mraa_i2c_write(dev->i2c, &cmd, 1))
+    {
+        printf("%s: mraa_i2c_write() failed.\n", __FUNCTION__);
+        return -1;
+    }
+
+    // delay for measurement
+    upm_delay_ms(MB704X_RANGE_DELAY);
+
+    // At this point, we should be able to do our read of the data
+    uint8_t buffer[2];
+    if (mraa_i2c_read(dev->i2c, buffer, 2) != 2)
+    {
+        printf("%s: mraa_i2c_read() failed.\n", __FUNCTION__);
+        return -1;
+    }
+
+    return ((buffer[0] << 8) | buffer[1]);
+}