rotaryencoder: Initial implementation

This module implements supoort for the Grove Rotary Encoder, though it
should function with any Rotary Encoder utilizing two GPIOs.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Zion Orent <zorent@ics.com>
Signed-off-by: John Van Drasek <john.r.van.drasek@intel.com>

src/rotaryencoder/CMakeLists.txt

@@ -0,0 +1,5 @@
+set (libname "rotaryencoder")
+set (libdescription "upm grove rotary encoder module")
+set (module_src ${libname}.cxx)
+set (module_h ${libname}.h)
+upm_module_init()

src/rotaryencoder/jsupm_rotaryencoder.i

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+%module jsupm_rotaryencoder
+%include "../upm.i"
+
+%{
+    #include "rotaryencoder.h"
+%}
+
+%include "rotaryencoder.h"

src/rotaryencoder/pyupm_rotaryencoder.i

@@ -0,0 +1,9 @@
+%module pyupm_rotaryencoder
+%include "../upm.i"
+
+%feature("autodoc", "3");
+
+%include "rotaryencoder.h"
+%{
+    #include "rotaryencoder.h"
+%}

src/rotaryencoder/rotaryencoder.cxx

@@ -0,0 +1,91 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * 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 <iostream>
+
+#include "rotaryencoder.h"
+
+using namespace upm;
+using namespace std;
+
+RotaryEncoder::RotaryEncoder(int pinA, int pinB)
+{
+  if ( !(m_gpioA = mraa_gpio_init(pinA)) )
+    {
+      cerr << __FUNCTION__ << ": mraa_gpio_init() failed" << endl;
+      return;
+    }
+
+  mraa_gpio_dir(m_gpioA, MRAA_GPIO_IN);
+
+  if ( !(m_gpioB = mraa_gpio_init(pinB)) )
+    {
+      cerr << __FUNCTION__ << ": mraa_gpio_init() failed" << endl;
+      return;
+    }
+
+  mraa_gpio_dir(m_gpioB, MRAA_GPIO_IN);
+
+  m_position = 0;
+
+  // setup the ISR
+
+  // We would prefer to use MRAA_GPIO_EDGE_BOTH for better resolution,
+  // but that does not appear to be supported
+  mraa_gpio_isr(m_gpioA, MRAA_GPIO_EDGE_RISING, 
+                &signalAISR, this);
+}
+
+RotaryEncoder::~RotaryEncoder()
+{
+  mraa_gpio_isr_exit(m_gpioA);
+
+  mraa_gpio_close(m_gpioA);
+  mraa_gpio_close(m_gpioB);
+}
+
+void RotaryEncoder::initPosition(int count)
+{
+  m_position = count;
+}
+
+int RotaryEncoder::position()
+{
+  return m_position;
+}
+
+void RotaryEncoder::signalAISR(void *ctx)
+{
+  upm::RotaryEncoder *This = (upm::RotaryEncoder *)ctx;
+
+  if (mraa_gpio_read(This->m_gpioA))
+    {
+      if (mraa_gpio_read(This->m_gpioB))
+        This->m_position++;      // CW
+      else
+        This->m_position--;      // CCW
+    }
+}
+
+

src/rotaryencoder/rotaryencoder.h

@@ -0,0 +1,91 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * 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 <string>
+#include <stdint.h>
+#include <sys/time.h>
+#include <mraa/gpio.h>
+
+namespace upm {
+
+  /**
+   * @brief C++ API for the Grove Rotary Encoder
+   *
+   * UPM module for the Grove Rotary Encoder.  A Rotary Encoder
+   * encodes a rotation signal into electronic pulses that can be used
+   * to measure rotation and direction.  It is useful in cases where a
+   * rotary knob is required, but using a potentiometer is not
+   * desireable.  A rotary encoder can turn a full 360 degrees+
+   * without a stop and does not place a resistive load on the
+   * circuit, as is the case with a potentiometer.
+   *
+   * This module maintains a position that is incremented or
+   * decremented according to the rotation on the encoder.
+   *
+   * @ingroup gpio 
+   * @snippet rotaryencoder.cxx Interesting
+   */
+  class RotaryEncoder {
+  public:
+    /**
+     * RotaryEncoder constructor
+     *
+     * @param pinA digital pin to use for signal A
+     * @param pinB digital pin to use for signal B
+     */
+    RotaryEncoder(int pinA, int pinB);
+    /**
+     * RotaryEncoder Destructor
+     */
+    ~RotaryEncoder();
+
+    /**
+     * Reset the position to a given number, default is 0. 
+     *
+     * @param count integer to initialize the position to
+     */
+    void initPosition(int count=0);
+
+    /**
+     * Get the position value
+     *
+     */
+    int position();
+
+    /**
+     * ISR for signal A
+     *
+     * @param ctx user context for the ISR (*this pointer)
+     */
+    static void signalAISR(void *ctx);
+
+  private:
+    volatile int m_position;
+    mraa_gpio_context m_gpioA;
+    mraa_gpio_context m_gpioB;
+  };
+}
+
+