wheelencoder: Initial implementation

This driver was developed for the DFRobot Wheel Encoder, though it
could be used for any counting time-based task using a digital i/o pin
to generate interrupts.

http://www.dfrobot.com/index.php?route=product/product&product_id=98

If you want to use more than one encoder, simply create a class
instance for each one.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: sisinty sasmita patra <sisinty.s.patra@intel.com>

src/wheelencoder/CMakeLists.txt

@@ -0,0 +1,5 @@
+set (libname "wheelencoder")
+set (libdescription "upm DFRobot wheelencoder")
+set (module_src ${libname}.cxx)
+set (module_h ${libname}.h)
+upm_module_init()

src/wheelencoder/javaupm_wheelencoder.i

@@ -0,0 +1,8 @@
+%module javaupm_wheelencoder
+%include "../upm.i"
+
+%{
+    #include "wheelencoder.h"
+%}
+
+%include "wheelencoder.h"

src/wheelencoder/jsupm_wheelencoder.i

@@ -0,0 +1,8 @@
+%module jsupm_wheelencoder
+%include "../upm.i"
+
+%{
+    #include "wheelencoder.h"
+%}
+
+%include "wheelencoder.h"

src/wheelencoder/pyupm_wheelencoder.i

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

src/wheelencoder/wheelencoder.cxx

@@ -0,0 +1,106 @@
+/*
+ * 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 "wheelencoder.h"
+
+using namespace upm;
+using namespace std;
+
+WheelEncoder::WheelEncoder(int pin) :
+  m_gpio(pin)
+{
+  m_gpio.dir(mraa::DIR_IN);
+
+  initClock();
+  m_counter = 0;
+  m_isrInstalled = false;
+}
+
+WheelEncoder::~WheelEncoder()
+{
+  stopCounter();
+}
+
+void WheelEncoder::initClock()
+{
+  gettimeofday(&m_startTime, NULL);
+}
+
+uint32_t WheelEncoder::getMillis()
+{
+  struct timeval elapsed, now;
+  uint32_t elapse;
+
+  // get current time
+  gettimeofday(&now, NULL);
+
+  // compute the delta since m_startTime
+  if( (elapsed.tv_usec = now.tv_usec - m_startTime.tv_usec) < 0 ) 
+    {
+      elapsed.tv_usec += 1000000;
+      elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec - 1;
+    } 
+  else 
+    {
+      elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec;
+    }
+
+  elapse = (uint32_t)((elapsed.tv_sec * 1000) + (elapsed.tv_usec / 1000));
+
+  // never return 0
+  if (elapse == 0)
+    elapse = 1;
+
+  return elapse;
+}
+
+void WheelEncoder::startCounter()
+{
+  initClock();
+  m_counter = 0;
+
+  // install our interrupt handler
+  if (!m_isrInstalled)
+    m_gpio.isr(mraa::EDGE_RISING, &wheelISR, this);
+
+  m_isrInstalled = true;
+}
+
+void WheelEncoder::stopCounter()
+{
+  // remove the interrupt handler
+  if (m_isrInstalled)
+    m_gpio.isrExit();
+
+  m_isrInstalled = false;
+}
+
+void WheelEncoder::wheelISR(void *ctx)
+{
+  upm::WheelEncoder *This = (upm::WheelEncoder *)ctx;
+  This->m_counter++;
+}
+

src/wheelencoder/wheelencoder.h

@@ -0,0 +1,131 @@
+/*
+ * 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.hpp>
+
+namespace upm {
+
+  /**
+   * @brief DFRobot Wheel Encoder library
+   * @defgroup wheelencoder libupm-wheelencoder
+   * @ingroup dfrobot gpio other
+   */
+
+  /**
+   * @library libupm-wheelencoder
+   * @sensor wheelencoder
+   * @comname DFRobot Wheel Encoder
+   * @type other
+   * @man dfrobot
+   * @web http://www.dfrobot.com/index.php?route=product/product&product_id=98
+   * @con gpio
+
+   * @brief API for the DFRobot Wheel Encoder
+   *
+   * This sensor was developed for the DFRobot Wheel Encoder, though
+   * it could be used for any counting time-based task.
+   * 
+   * When you instantiate a class of this type, the gpio pin specified
+   * is connected to an interrupt.  Whenever a low to high transition
+   * occurs on the gpio pin, the internal counter is incremented by
+   * one.
+   *
+   * This class also includes a millisecond counter, so that you can
+   * correlate the number of counts to a time period for calculating
+   * an RPM or other value as needed.
+   *
+   * @snippet wheelencoder.cxx Interesting
+   */
+  class WheelEncoder {
+  public:
+
+    /**
+     * DFRobot Wheel Encoder sensor constructor
+     *
+     * @param pin Digital pin to use
+     */
+    WheelEncoder(int pin);
+
+    /**
+     * WheelEncoder destructor
+     */
+    ~WheelEncoder();
+
+    /**
+     * Returns the number of milliseconds elapsed since initClock()
+     * was last called.
+     *
+     * @return Elapsed milliseconds
+     */
+    uint32_t getMillis();
+
+    /**
+     * Resets the clock
+     *
+     */
+    void initClock();
+
+    /**
+     * Resets the counter to 0. The counter should be
+     * stopped via stopCounter() prior to calling this function.
+     *
+     */
+    void clearCounter() { m_counter = 0; };
+
+    /**
+     * Starts the counter.  This function will also clear the current
+     * count and reset the clock.
+     *
+     */
+    void startCounter();
+
+    /**
+     * Stops the counter
+     *
+     */
+    void stopCounter();
+
+    /**
+     * Gets the current counter value
+     *
+     * @return counter value
+     */
+    uint32_t counter() { return m_counter; };
+
+  protected:
+    mraa::Gpio m_gpio;
+    static void wheelISR(void *ctx);
+
+  private:
+    volatile uint32_t m_counter;
+    struct timeval m_startTime;
+    bool m_isrInstalled;
+  };
+}
+
+