lm35: add C driver and example; FTI; C++ wraps C

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

src/lm35/lm35.h

@@ -0,0 +1,104 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2016 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 <stdlib.h>
+#include <stdio.h>
+#include <upm.h>
+#include <mraa/aio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    /**
+     * @file lm35.h
+     * @library lm35
+     * @brief C API for the LM35 Temperature Sensor
+     *
+     * @include lm35.c
+     */
+
+    /**
+     * device context
+     */
+    typedef struct _lm35_context
+    {
+        mraa_aio_context    aio;
+
+        // ADC reference voltage
+        float               aref;
+        // ADC resolution
+        float               ares;
+
+        // scale and offset
+        float               scale;
+        float               offset;
+    } *lm35_context;
+
+    /**
+     * LM35 initialization.
+     *
+     * @param pin Analog pin to use
+     * @param aref Analog reference voltage
+     */
+    lm35_context lm35_init(int pin, float aref);
+
+    /**
+     * LM35 close.
+     */
+    void lm35_close(lm35_context dev);
+
+    /**
+     * Returns the temperature in degrees Celsius
+     *
+     * @param temperature A pointer to a float that will contain the
+     * measured temperature.
+     * @return UPM status
+     */
+    upm_result_t lm35_get_temperature(const lm35_context dev,
+                                      float *temperature);
+
+    /**
+     * Set sensor offset.  This offset is applied to the return values
+     * before scaling.  Default is 0.0.
+     *
+     * @param dev sensor context pointer
+     * @param offset Offset to apply.
+     */
+    void lm35_set_offset(const lm35_context dev, float offset);
+
+    /**
+     * Set sensor scale.  This scale is applied to the return values
+     * before the offset is applied.  Default is 1.0.
+     *
+     * @param dev sensor context pointer
+     * @param scale Scale to apply.
+     */
+    void lm35_set_scale(const lm35_context dev, float scale);
+
+
+#ifdef __cplusplus
+}
+#endif