grovewfs: Initial implementation

This driver implements support for the Grove Water Flow sensor.  It
uses an integrated hall effect sensor, connected to a GPIO configured
as an interrupt, to compute water flow in LPM (Liters Per Minute).

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/grovewfs/CMakeLists.txt

@@ -0,0 +1,5 @@
+set (libname "grovewfs")
+set (libdescription "upm grove water flow sensor module")
+set (module_src ${libname}.cxx)
+set (module_h ${libname}.h)
+upm_module_init()

src/grovewfs/grovewfs.cxx

@@ -0,0 +1,121 @@
+/*
+ * 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 "grovewfs.h"
+
+using namespace upm;
+using namespace std;
+
+GroveWFS::GroveWFS(int pin)
+{
+  if ( !(m_gpio = mraa_gpio_init(pin)) )
+    {
+      cerr << __FUNCTION__ << ": mraa_gpio_init() failed" << endl;
+      return;
+    }
+
+  mraa_gpio_dir(m_gpio, MRAA_GPIO_IN);
+
+  initClock();
+  m_flowCounter = 0;
+  m_isrInstalled = false;
+}
+
+GroveWFS::~GroveWFS()
+{
+  if (m_isrInstalled)
+    stopFlowCounter();
+
+  mraa_gpio_close(m_gpio);
+}
+
+void GroveWFS::initClock()
+{
+  gettimeofday(&m_startTime, NULL);
+}
+
+uint32_t GroveWFS::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 GroveWFS::startFlowCounter()
+{
+  initClock();
+  // install our interrupt handler
+  mraa_gpio_isr(m_gpio, MRAA_GPIO_EDGE_RISING, 
+                &flowISR, this);
+
+  m_isrInstalled = true;
+}
+
+void GroveWFS::stopFlowCounter()
+{
+  // remove the interrupt handler
+  mraa_gpio_isr_exit(m_gpio);
+
+  m_isrInstalled = false;
+}
+
+void GroveWFS::flowISR(void *ctx)
+{
+  upm::GroveWFS *This = (upm::GroveWFS *)ctx;
+  This->m_flowCounter++;
+}
+
+float GroveWFS::flowRate()
+{
+  uint32_t millis = getMillis();
+  uint32_t flow = flowCounter();
+  
+  // 7.5 comes from the seeedstudio page, see the confusing datasheet :)
+  float flowRate = (float(flow) * 7.5) / ((float(millis) / 1000.0) * 60.0);
+
+  return flowRate;
+}

src/grovewfs/grovewfs.h

@@ -0,0 +1,137 @@
+/*
+ * 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 UPM module for the Grove Water Flow sensor
+   * @defgroup grovewfs libupm-grovewfs
+   * @ingroup seeed gpio liquid
+   */
+
+  /**
+   * @sensor grovewfs
+   * @comname Grove Water Flow Sensor
+   * @type liquid
+   * @man seeed
+   * @con gpio
+
+   * @brief C++ API for the Grove Water Flow Sensor
+   *
+   * This sensor is used to measure water flow, in LPM (Liters Per
+   * Minute).  It incorporates a Hall Effect Sensor.  The UPM module
+   * defines an interrupt routine to be triggered on each low pulse,
+   * keeping count.  This device requires a 10K pullup resistor for
+   * the signal line (yellow wire).  There is a schematic diagram on
+   * the seeedstudio site (3/2015):
+   * http://www.seeedstudio.com/wiki/index.php?title=G1/2_Water_Flow_sensor
+   *
+   * However, be careful in wiring this up - the schematic appears to
+   * have a bug in it: the lower left connection of the signal line
+   * (yellow) to Vcc (red) should not be there.  The sensor may work
+   * with this connection, but probably not for very long.
+   *
+   *
+   * @snippet grovewfs.cxx Interesting
+   */
+  class GroveWFS {
+  public:
+    /**
+     * GroveWFS constructor
+     *
+     * @param pin digital pin to use
+     */
+    GroveWFS(int pin);
+    /**
+     * GroveWFS Destructor
+     */
+    ~GroveWFS();
+    /**
+     * Return the number of milliseconds elapsed since initClock()
+     * was last called.
+     *
+     * @return elapsed milliseconds
+     */
+    uint32_t getMillis();
+
+    /**
+     * Reset the Clock
+     *
+     */
+    void initClock();
+
+    /**
+     * Reset the flow counter to 0.  The flow Counter should be
+     * stopped via stopFlowCounter() prior to calling this function.
+     *
+     */
+    void clearFlowCounter() { m_flowCounter = 0; };
+
+    /**
+     * Start the flow counter
+     *
+     */
+    void startFlowCounter();
+
+    /**
+     * Stop the flow counter
+     *
+     */
+    void stopFlowCounter();
+
+    /**
+     * Get the flow Counter
+     *
+     * @return the flow counter
+     */
+    uint32_t flowCounter() { return m_flowCounter; };
+
+    /**
+     * Flow Interrupt Service Routine
+     *
+     */
+    static void flowISR(void *ctx);
+
+    /**
+     * Compute the flow rate in liters per minute (LPM)
+     *
+     * @return the computed flow rate
+     */
+    float flowRate();
+
+  private:
+    volatile uint32_t m_flowCounter;
+    struct timeval m_startTime;
+    mraa_gpio_context m_gpio;
+    bool m_isrInstalled;
+  };
+}
+
+

src/grovewfs/jsupm_grovewfs.i

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

src/grovewfs/pyupm_grovewfs.i

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