bh1750: Initial implementation

This driver was developed with the DFRobot Light Sensor based on the
BH1750.  It has a sensitivity of .5 to 65535 Lux.  It supports
voltages from 3-5vdc and is connected via I2C.

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

src/bh1750/bh1750.hpp

@@ -0,0 +1,134 @@
+/*
+ * 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 <string>
+#include <iostream>
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "bh1750.h"
+
+namespace upm {
+    /**
+     * @brief DFRobot Light Sensor (BH1750)
+     * @defgroup bh1750 libupm-bh1750
+     * @ingroup dfrobot i2c
+     */
+
+    /**
+     * @library bh1750
+     * @sensor bh1750
+     * @comname DFRobot Light Sensor
+     * @type light
+     * @man dfrobot
+     * @con i2c
+     * @web http://www.dfrobot.com/index.php?route=product/product&product_id=531
+     *
+     * @brief UPM C API for the DFRobot I2C BH1750 Light Sensor
+     *
+     * This driver was developed with the DFRobot Light Sensor based on
+     * the BH1750.  It has a sensitivity of .5 10 65535 Lux.  It supports
+     * voltages from 3-5vdc and is connected via I2C.
+     *
+     * @snippet bh1750.cxx Interesting
+     */
+
+  class BH1750 {
+  public:
+
+    /**
+     * BH1750 object constructor (Analog mode)
+     *
+     * @param bus The I2C bus to use 
+     * @param addr The I2C address of the device
+     * @param mode The mode to start operation under.  One of the
+     * BH1750_OPMODES_T values.  The default is the highest precision,
+     * lowest power mode.
+     */
+    BH1750(int bus=BH1750_DEFAULT_I2C_BUS, int addr=BH1750_DEFAULT_I2C_ADDR,
+           BH1750_OPMODES_T mode=BH1750_OPMODE_H2_ONCE);
+
+    /**
+     * BH1750 object destructor
+     */
+    ~BH1750();
+
+    /**
+     * Reset the device.  This doesn't really have much purpose.  The
+     * device must be powered up for this command to work.  In
+     * addition, this command will simply clear the measurement
+     * register to 0.
+     */
+    void reset();
+
+    /**
+     * Get the measured light intensity in Lux.
+     *
+     * @return The measured light intensity in Lux.
+     */
+    float getLux();
+
+    /**
+     * Power up the device.
+     */
+    void powerUp();
+
+    /**
+     * Power down the device.
+     */
+    void powerDown();
+
+    /**
+     * Setup the device to match the selected operating mode.
+     *
+     * @param mode operating mode, one of the BH1750_OPMODES_T values
+     */
+    void setOpmode(BH1750_OPMODES_T mode);
+
+  protected:
+    // bh1750 device context
+    bh1750_context m_bh1750;
+
+    /**
+     * Sends a command to the device via I2C.
+     *
+     * @param cmd The command to write, one of the BH1750_CMD* values
+     */
+    void sendCommand(uint8_t cmd);
+
+    /**
+     * Read the 2 result bytes from the device via I2C.
+     *
+     * @return Data read in from the device as a uint16_t
+     */
+    uint16_t readData();
+
+  private:
+  };
+}
+
+