upm/src/wfs/wfs.c

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/*
* Author: Jon Trulson <jtrulson@ics.com>
* Copyright (c) 2017 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 <stdio.h>
#include <string.h>
#include <assert.h>
#include "wfs.h"
// interrupt handler
static void wfs_flow_isr(void *ctx)
{
assert(ctx != NULL);
wfs_context dev = (wfs_context)ctx;
dev->flowCounter++;
}
wfs_context wfs_init(int pin)
{
// make sure MRAA is initialized
int mraa_rv;
if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
{
printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
return NULL;
}
wfs_context dev =
(wfs_context)malloc(sizeof(struct _wfs_context));
if (!dev)
return NULL;
// zero out context
memset((void *)dev, 0, sizeof(struct _wfs_context));
if ( !(dev->gpio = mraa_gpio_init(pin)) )
{
printf("%s: mraa_gpio_init() failed.\n", __FUNCTION__);
wfs_close(dev);
return NULL;
}
mraa_gpio_dir(dev->gpio, MRAA_GPIO_IN);
wfs_init_clock(dev);
return dev;
}
void wfs_close(wfs_context dev)
{
assert(dev != NULL);
if (dev->isrInstalled)
wfs_stop_flow_counter(dev);
if (dev->gpio)
mraa_gpio_close(dev->gpio);
free(dev);
}
void wfs_init_clock(const wfs_context dev)
{
assert(dev != NULL);
upm_clock_init(&dev->clock);
}
uint32_t wfs_get_millis(const wfs_context dev)
{
assert(dev != NULL);
return upm_elapsed_ms(&dev->clock);
}
void wfs_clear_flow_counter(const wfs_context dev)
{
assert(dev != NULL);
dev->flowCounter = 0;
}
upm_result_t wfs_start_flow_counter(const wfs_context dev)
{
assert(dev != NULL);
wfs_init_clock(dev);
// install our interrupt handler
if (mraa_gpio_isr(dev->gpio, MRAA_GPIO_EDGE_RISING,
&wfs_flow_isr, dev))
{
printf("%s: mraa_gpio_isr() failed.\n", __FUNCTION__);
return UPM_ERROR_OPERATION_FAILED;
}
dev->isrInstalled = true;
return UPM_SUCCESS;
}
void wfs_stop_flow_counter(const wfs_context dev)
{
assert(dev != NULL);
// remove the interrupt handler
mraa_gpio_isr_exit(dev->gpio);
dev->isrInstalled = false;
}
uint32_t wfs_flow_counter(const wfs_context dev)
{
assert(dev != NULL);
return dev->flowCounter;
}
float wfs_flow_rate(const wfs_context dev)
{
assert(dev != NULL);
uint32_t millis = wfs_get_millis(dev);
uint32_t flow = wfs_flow_counter(dev);
// 7.5 comes from the seeedstudio page, see the confusing datasheet :)
return ((float)flow * 7.5) / ( ((float)millis / 1000.0) * 60.0);
}