enc03r: C port; FTI; C++ wraps C

The API for this driver has changed.  See docs/apichanges.md.

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

src/enc03r/enc03r.c

@@ -0,0 +1,158 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2014-2017 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 <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "enc03r.h"
+
+enc03r_context enc03r_init(int pin, float aref)
+{
+    // 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;
+    }
+
+    enc03r_context dev =
+        (enc03r_context)malloc(sizeof(struct _enc03r_context));
+
+    if (!dev)
+        return NULL;
+
+    // zero out context
+    memset((void *)dev, 0, sizeof(struct _enc03r_context));
+
+    dev->a_ref = aref;
+
+    if ( !(dev->aio = mraa_aio_init(pin)) )
+    {
+        printf("%s: mraa_aio_init() failed.\n", __FUNCTION__);
+        enc03r_close(dev);
+        return NULL;
+    }
+
+    dev->offset = 0.0;
+    dev->scale = 1.0;
+
+    dev->a_res = (float)(1 << mraa_aio_get_bit(dev->aio)) - 1.0;
+
+    dev->calibrationValue = 0.0;
+
+    return dev;
+}
+
+void enc03r_close(enc03r_context dev)
+{
+    assert(dev != NULL);
+
+    if (dev->aio)
+        mraa_aio_close(dev->aio);
+
+    free(dev);
+}
+
+upm_result_t enc03r_update(enc03r_context dev)
+{
+    assert(dev != NULL);
+
+    float val = (float)mraa_aio_read(dev->aio);
+    if (val < 0)
+    {
+        printf("%s: mraa_aio_read() failed\n", __FUNCTION__);
+        return UPM_ERROR_OPERATION_FAILED;
+    }
+
+    dev->normalized = val / dev->a_res;
+
+    // from seeed studio example
+    dev->angular_velocity =
+        ((val - dev->calibrationValue) * (dev->a_ref * 1000.0)
+         / dev->a_res / 0.67);
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t enc03r_calibrate(const enc03r_context dev,
+                                   unsigned int samples)
+{
+    assert(dev != NULL);
+
+    float total = 0.0;
+
+    for (int i=0; i<samples; i++)
+    {
+        int val = mraa_aio_read(dev->aio);
+        if (val < 0)
+        {
+            printf("%s: mraa_aio_read() failed\n", __FUNCTION__);
+            return UPM_ERROR_OPERATION_FAILED;
+        }
+
+        total += (float)val;
+        upm_delay_ms(2);
+    }
+
+    dev->calibrationValue = total / (float)samples;
+
+    return UPM_SUCCESS;
+}
+
+float enc03r_calibration_value(const enc03r_context dev)
+{
+    assert(dev != NULL);
+
+    return dev->calibrationValue;
+}
+
+float enc03r_angular_velocity(const enc03r_context dev)
+{
+    assert(dev != NULL);
+
+    return dev->angular_velocity * dev->scale + (dev->offset * dev->scale);
+}
+
+void enc03r_set_offset(const enc03r_context dev, float offset)
+{
+    assert(dev != NULL);
+
+    dev->offset = offset;
+}
+
+void enc03r_set_scale(const enc03r_context dev, float scale)
+{
+    assert(dev != NULL);
+
+    dev->scale = scale;
+}
+
+float enc03r_get_normalized(const enc03r_context dev)
+{
+    assert(dev != NULL);
+
+    return dev->normalized;
+}