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.h

@@ -0,0 +1,151 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include "upm.h"
+#include "mraa/aio.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * device context
+ */
+typedef struct _joystick12_context {
+    /* mraa ai_x pin context */
+    mraa_aio_context ai_x;
+    /* mraa ai_y pin context */
+    mraa_aio_context ai_y;
+    /* Raw count offset - x axis */
+    float m_count_offset_x;
+    /* Raw count offset - y axis */
+    float m_count_offset_y;
+    /* Raw count scale - x axis */
+    float m_count_scale_x;
+    /* Raw count scale - y axis */
+    float m_count_scale_y;
+} *joystick12_context;
+
+/**
+ * Initialize analog sensor
+ * @param pin is Analog pin
+ * @return sensor context as void pointer
+ */
+joystick12_context joystick12_init(int16_t apin_x, int16_t apin_y);
+
+/**
+ * Analog sensor destructor
+ * @param sensor context pointer deallocate memory
+ */
+void joystick12_close(joystick12_context dev);
+
+/**
+ * Generic read joystick data method
+ * @param dev sensor device context pointer
+ * @param value pointer to an int[2] in which data is returned
+ */
+upm_result_t joystick12_read_data(const joystick12_context dev, int* values);
+
+/**
+ * Set sensor offset.  This offset is applied to the return value:
+ *     counts = counts + offset
+ * @param dev sensor context pointer
+ * @param offset count offset value used
+ * @return Function result code
+ */
+upm_result_t joystick12_set_offset_x(const joystick12_context dev,
+                                     float offset);
+
+/**
+ * Set sensor offset.  This offset is applied to the return value:
+ *     counts = counts + offset
+ * @param dev sensor context pointer
+ * @param offset count offset value used
+ * @return Function result code
+ */
+upm_result_t joystick12_set_offset_y(const joystick12_context dev,
+                                     float offset);
+
+/**
+ * Set sensor scale.  This scale is applied to the return value:
+ *     counts = counts * scale
+ * @param dev sensor context pointer
+ * @param scale count scale value used
+ * @return Function result code
+ */
+upm_result_t joystick12_set_scale_x(const joystick12_context dev, float scale);
+
+/**
+ * Set sensor scale.  This scale is applied to the return value:
+ *     counts = counts * scale
+ * @param dev sensor context pointer
+ * @param scale count scale value used
+ * @return Function result code
+ */
+upm_result_t joystick12_set_scale_y(const joystick12_context dev, float scale);
+
+/**
+ * Read value from sensor
+ * @param dev sensor context pointer
+ * @param *value normalized value from sensor, units depend on unit enum
+ * @param unit Enum which specifies units returned in *value
+ * @return Function result code
+ */
+upm_result_t joystick12_get_value_x(const joystick12_context dev, float *value);
+
+/**
+ * Read value from sensor
+ * @param dev sensor context pointer
+ * @param *value normalized value from sensor, units depend on unit enum
+ * @param unit Enum which specifies units returned in *value
+ * @return Function result code
+ */
+upm_result_t joystick12_get_value_y(const joystick12_context dev, float *value);
+
+/**
+ * Zero out the sensor x and y axis
+ * @param dev sensor context pointer
+ * @return Function result code
+ */
+upm_result_t joystick12_zero(const joystick12_context dev);
+
+/**
+ * Set x scale.  Move joystick to min or max x and call calibrate
+ * @param dev sensor context pointer
+ * @return Function result code
+ */
+upm_result_t joystick12_calibrate_x(const joystick12_context dev);
+
+/**
+ * Set y scale.  Move joystick to min or max y and call calibrate
+ * @param dev sensor context pointer
+ * @return Function result code
+ */
+upm_result_t joystick12_calibrate_y(const joystick12_context dev);
+
+#ifdef __cplusplus
+}
+#endif