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      1 /*
      2  * Author: Jon Trulson <jtrulson (at) ics.com>
      3  * Copyright (c) 2015 Intel Corporation.
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining
      6  * a copy of this software and associated documentation files (the
      7  * "Software"), to deal in the Software without restriction, including
      8  * without limitation the rights to use, copy, modify, merge, publish,
      9  * distribute, sublicense, and/or sell copies of the Software, and to
     10  * permit persons to whom the Software is furnished to do so, subject to
     11  * the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be
     14  * included in all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     17  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     21  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 #include <iostream>
     26 #include <string>
     27 #include <stdexcept>
     28 
     29 #include "rotaryencoder.h"
     30 
     31 using namespace upm;
     32 using namespace std;
     33 
     34 RotaryEncoder::RotaryEncoder(int pinA, int pinB)
     35 {
     36   if ( !(m_gpioA = mraa_gpio_init(pinA)) )
     37     {
     38       throw std::invalid_argument(std::string(__FUNCTION__) +
     39                                   ": mraa_gpio_init(pinA) failed, invalid pin?");
     40       return;
     41     }
     42 
     43   mraa_gpio_dir(m_gpioA, MRAA_GPIO_IN);
     44 
     45   if ( !(m_gpioB = mraa_gpio_init(pinB)) )
     46     {
     47       throw std::invalid_argument(std::string(__FUNCTION__) +
     48                                   ": mraa_gpio_init(pinB) failed, invalid pin?");
     49       return;
     50     }
     51 
     52   mraa_gpio_dir(m_gpioB, MRAA_GPIO_IN);
     53 
     54   m_position = 0;
     55 
     56   // setup the ISR
     57 
     58   // We would prefer to use MRAA_GPIO_EDGE_BOTH for better resolution,
     59   // but that does not appear to be supported
     60   mraa_gpio_isr(m_gpioA, MRAA_GPIO_EDGE_RISING,
     61                 &signalAISR, this);
     62 }
     63 
     64 RotaryEncoder::~RotaryEncoder()
     65 {
     66   mraa_gpio_isr_exit(m_gpioA);
     67 
     68   mraa_gpio_close(m_gpioA);
     69   mraa_gpio_close(m_gpioB);
     70 }
     71 
     72 void RotaryEncoder::initPosition(int count)
     73 {
     74   m_position = count;
     75 }
     76 
     77 int RotaryEncoder::position()
     78 {
     79   return m_position;
     80 }
     81 
     82 void RotaryEncoder::signalAISR(void *ctx)
     83 {
     84   upm::RotaryEncoder *This = (upm::RotaryEncoder *)ctx;
     85 
     86   if (mraa_gpio_read(This->m_gpioA))
     87     {
     88       if (mraa_gpio_read(This->m_gpioB))
     89         This->m_position++;      // CW
     90       else
     91         This->m_position--;      // CCW
     92     }
     93 }
     94 
     95 
     96