joystick12: Added 2 axis analog joystick12 C sensor

Added the C source for the joystick12 with necessary changes to cmake,
examples, and docs.

Signed-off-by: Noel Eck <noel.eck@intel.com>

src/joystick12/joystick12.c

@@ -0,0 +1,206 @@
+/*
+ * Author:
+ * Copyright (c) 2015 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 <stdlib.h>
+
+#include "joystick12.h"
+
+joystick12_context joystick12_init(int16_t apin_x, int16_t apin_y)
+{
+    joystick12_context dev =
+      (joystick12_context) malloc(sizeof(struct _joystick12_context));
+
+    if(dev == NULL) return NULL;
+
+    /* Init analog pins */
+    dev->ai_x = mraa_aio_init(apin_x);
+    dev->ai_y = mraa_aio_init(apin_y);
+
+    /* Set the ref, zero the offset */
+    dev->m_count_offset_x = 0.0;
+    dev->m_count_scale_x = 2.0;
+    dev->m_count_offset_y = 0.0;
+    dev->m_count_scale_y = 2.0;
+
+    if((dev->ai_x == NULL) || (dev->ai_y == NULL))
+    {
+        free(dev);
+        return NULL;
+    }
+
+    return dev;
+}
+
+void joystick12_close(joystick12_context dev)
+{
+    mraa_aio_close(dev->ai_x);
+    mraa_aio_close(dev->ai_y);
+    free(dev);
+}
+
+upm_result_t joystick12_read_data(const joystick12_context dev, int* values)
+{
+    /* Throw away first read */
+    mraa_aio_read(dev->ai_x);
+    values[0] = mraa_aio_read(dev->ai_x);
+    /* Throw away first read */
+    mraa_aio_read(dev->ai_y);
+    values[1] = mraa_aio_read(dev->ai_y);
+
+    if (values[0] < 0 || values[1] < 0)
+        return UPM_ERROR_OPERATION_FAILED;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_set_offset_x(const joystick12_context dev, float offset)
+{
+    dev->m_count_offset_x = offset;
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_set_offset_y(const joystick12_context dev, float offset)
+{
+    dev->m_count_offset_y = offset;
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_set_scale_x(const joystick12_context dev, float scale)
+{
+    dev->m_count_scale_x = scale;
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_set_scale_y(const joystick12_context dev, float scale)
+{
+    dev->m_count_scale_y = scale;
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_get_value_x(const joystick12_context dev, float *value)
+{
+    int counts[2] = {0,0};
+
+    /* Read counts from the generic read method */
+    joystick12_read_data(dev, counts);
+
+    /* Get max adc value range 1023, 2047, 4095, etc... */
+    float max_adc = (1 << mraa_aio_get_bit(dev->ai_x)) - 1;
+
+    /* Apply raw offset */
+    *value = counts[0] + dev->m_count_offset_x;
+
+    // Scale to +/- 1.0
+    *value =  -2.0 * (((max_adc/2.0 - *value))/max_adc * dev->m_count_scale_x);
+
+    // Clip to +/- 1.0
+    if (*value > 1.0) *value = 1.0;
+    else if (*value < -1.0) *value = -1.0;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_get_value_y(const joystick12_context dev, float *value)
+{
+    int counts[2] = {0,0};
+
+    /* Read counts from the generic read method */
+    joystick12_read_data(dev, counts);
+
+    /* Get max adc value range 1023, 2047, 4095, etc... */
+    float max_adc = (1 << mraa_aio_get_bit(dev->ai_y)) - 1;
+
+    /* Apply raw offset */
+    *value = counts[1] + dev->m_count_offset_y;
+
+    // Scale to +/- 1.0
+    *value =  -2.0 * (((max_adc/2.0 - *value))/max_adc * dev->m_count_scale_y);
+
+    // Clip to +/- 1.0
+    if (*value > 1.0) *value = 1.0;
+    else if (*value < -1.0) *value = -1.0;
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_zero(const joystick12_context dev)
+{
+    int counts[2] = {0, 0};
+
+    /* Read counts from the generic read method */
+    joystick12_read_data(dev, counts);
+
+    /* Get max adc value range 1023, 2047, 4095, etc... */
+    float max_adc = (1 << mraa_aio_get_bit(dev->ai_y)) - 1;
+
+    dev->m_count_offset_x = max_adc/2.0 - counts[0];
+    dev->m_count_offset_y = max_adc/2.0 - counts[1];
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_calibrate_x(const joystick12_context dev)
+{
+    int counts[2] = {0, 0};
+
+    /* Read counts from the generic read method */
+    joystick12_read_data(dev, counts);
+
+    /* Get max adc value range 1023, 2047, 4095, etc... */
+    float max_adc = (1 << mraa_aio_get_bit(dev->ai_y)) - 1;
+
+    float fcounts = counts[0];
+
+    /* no need to scale if counts is a max or min value */
+    if ((fcounts == 0) || (fcounts == max_adc)) return UPM_SUCCESS;
+
+    dev->m_count_scale_x =
+      1.0 / (1.0 - 2.0 * fcounts/max_adc);
+    dev->m_count_scale_x = fabs(dev->m_count_scale_x);
+
+    return UPM_SUCCESS;
+}
+
+upm_result_t joystick12_calibrate_y(const joystick12_context dev)
+{
+    int counts[2] = {0, 0};
+
+    /* Read counts from the generic read method */
+    joystick12_read_data(dev, counts);
+
+    /* Get max adc value range 1023, 2047, 4095, etc... */
+    float max_adc = (1 << mraa_aio_get_bit(dev->ai_y)) - 1;
+
+    float fcounts = counts[1];
+
+    /* no need to scale if counts is a max or min value */
+    if ((fcounts == 0) || (fcounts == max_adc)) return UPM_SUCCESS;
+
+    dev->m_count_scale_y =
+      1.0 / (1.0 - 2.0 * fcounts/max_adc);
+    dev->m_count_scale_y = fabs(dev->m_count_scale_y);
+
+    return UPM_SUCCESS;
+}