wfs: C port; C++ wraps C

Signed-off-by: Jon Trulson <jtrulson@ics.com>

src/wfs/wfs.h

@@ -0,0 +1,134 @@
+/*
+ * 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.
+ */
+#pragma once
+
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <upm.h>
+#include <upm_utilities.h>
+#include <mraa/gpio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    /**
+     * @file wfs.h
+     * @library wfs
+     * @brief WFS (Water Flow Sensor)
+     *
+     */
+
+    /**
+     * Device context
+     */
+    typedef struct _wfs_context {
+        mraa_gpio_context gpio;
+
+        volatile uint32_t flowCounter;
+        upm_clock_t       clock;
+        bool              isrInstalled;
+    } *wfs_context;
+
+    /**
+     * Initialize a WFS device
+     *
+     * @param pin GPIO pin to use.  This must be an interrupt capable
+     * pin.
+     * @return Device context, or NULL on error
+     */
+    wfs_context wfs_init(int pin);
+
+    /**
+     * WFS close function
+     *
+     * @param dev Device context
+     */
+    void wfs_close(wfs_context dev);
+
+    /**
+     * Returns the number of milliseconds elapsed since wfs_init_clock()
+     * was last called.
+     *
+     * @param dev Device context
+     * @return Elapsed milliseconds
+     */
+    uint32_t wfs_get_millis(const wfs_context dev);
+
+    /**
+     * Resets the clock
+     *
+     * @param dev Device context
+     */
+    void wfs_init_clock(const wfs_context dev);
+
+    /**
+     * Resets the flow counter to 0. The flow counter should be
+     * stopped via stopFlowCounter() prior to calling this function.
+     *
+     * @param dev Device context
+     */
+    void wfs_clear_flow_counter(const wfs_context dev);
+
+    /**
+     * Starts the flow counter
+     *
+     * @param dev Device context
+     * @return UPM result
+     */
+    upm_result_t wfs_start_flow_counter(const wfs_context dev);
+
+    /**
+     * Stops the flow counter
+     *
+     * @param dev Device context
+     */
+    void wfs_stop_flow_counter(const wfs_context dev);
+
+    /**
+     * Gets the flow counter
+     *
+     * @param dev Device context
+     * @return Flow counter
+     */
+    uint32_t wfs_flow_counter(const wfs_context dev);
+
+    /**
+     * Computes the flow rate in liters per minute (LPM).  Note, this
+     * is for the Grove WFS.  If you are using some other WFS, you
+     * should compute the flow rate on your own based on the data for
+     * your sensor.
+     *
+     * @param dev Device context
+     * @return Computed flow rate in liters per minute
+     */
+    float wfs_flow_rate(const wfs_context dev);
+
+
+#ifdef __cplusplus
+}
+#endif