1 /*
2 * Author: Jon Trulson <jtrulson@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 "grovewfs.h"
30
31 using namespace upm;
32 using namespace std;
33
GroveWFS(int pin)34 GroveWFS::GroveWFS(int pin)
35 {
36 if ( !(m_gpio = mraa_gpio_init(pin)) )
37 {
38 throw std::invalid_argument(std::string(__FUNCTION__) +
39 ": mraa_gpio_init() failed, invalid pin?");
40 return;
41 }
42
43 mraa_gpio_dir(m_gpio, MRAA_GPIO_IN);
44
45 initClock();
46 m_flowCounter = 0;
47 m_isrInstalled = false;
48 }
49
~GroveWFS()50 GroveWFS::~GroveWFS()
51 {
52 if (m_isrInstalled)
53 stopFlowCounter();
54
55 mraa_gpio_close(m_gpio);
56 }
57
initClock()58 void GroveWFS::initClock()
59 {
60 gettimeofday(&m_startTime, NULL);
61 }
62
getMillis()63 uint32_t GroveWFS::getMillis()
64 {
65 struct timeval elapsed, now;
66 uint32_t elapse;
67
68 // get current time
69 gettimeofday(&now, NULL);
70
71 // compute the delta since m_startTime
72 if( (elapsed.tv_usec = now.tv_usec - m_startTime.tv_usec) < 0 )
73 {
74 elapsed.tv_usec += 1000000;
75 elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec - 1;
76 }
77 else
78 {
79 elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec;
80 }
81
82 elapse = (uint32_t)((elapsed.tv_sec * 1000) + (elapsed.tv_usec / 1000));
83
84 // never return 0
85 if (elapse == 0)
86 elapse = 1;
87
88 return elapse;
89 }
90
startFlowCounter()91 void GroveWFS::startFlowCounter()
92 {
93 initClock();
94 // install our interrupt handler
95 mraa_gpio_isr(m_gpio, MRAA_GPIO_EDGE_RISING,
96 &flowISR, this);
97
98 m_isrInstalled = true;
99 }
100
stopFlowCounter()101 void GroveWFS::stopFlowCounter()
102 {
103 // remove the interrupt handler
104 mraa_gpio_isr_exit(m_gpio);
105
106 m_isrInstalled = false;
107 }
108
flowISR(void * ctx)109 void GroveWFS::flowISR(void *ctx)
110 {
111 upm::GroveWFS *This = (upm::GroveWFS *)ctx;
112 This->m_flowCounter++;
113 }
114
flowRate()115 float GroveWFS::flowRate()
116 {
117 uint32_t millis = getMillis();
118 uint32_t flow = flowCounter();
119
120 // 7.5 comes from the seeedstudio page, see the confusing datasheet :)
121 float flowRate = (float(flow) * 7.5) / ((float(millis) / 1000.0) * 60.0);
122
123 return flowRate;
124 }
125