mpr121: Initial implementation

This module implements support for the Grove I2C touch sensor
(mpr121).

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/mpr121/mpr121.h

@@ -0,0 +1,108 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2014 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 <mraa/i2c.h>
+
+#define MPR121_I2C_BUS     0
+#define MPR121_DEFAULT_I2C_ADDR    0x5a
+
+namespace upm {
+
+  /**
+   * @brief C++ API for the MPR121 I2C touch sensor
+   *
+   * UPM module for the MPR121 touch sensor
+   *
+   * @ingroup i2c mpr121
+   * @snippet mpr121.cxx Interesting
+   */
+  class MPR121 {
+  public:
+    /**
+     * mpr121 touch sensor constructor
+     *
+     * @param bus i2c bus to use
+     */
+    MPR121(int bus, uint8_t address = MPR121_DEFAULT_I2C_ADDR);
+
+    /**
+     * MPR121 Destructor
+     */
+    ~MPR121();
+
+    /**
+     * Setup a default configuration, based on Application Note 3944
+     * (AN3944):
+     * http://cache.freescale.com/files/sensors/doc/app_note/AN3944.pdf
+     *
+     * After configuration, the sensor will be left in the Run State.
+     *
+     * @return True if configuration succeeded
+     */
+    bool configAN3944();
+
+    /**
+     * Read the button states into the m_buttonStates member variable.  Also
+     * set the m_overCurrentFault variable if an over current is detected.
+     */
+    void readButtons();
+
+    /**
+     * Write value(s) into registers
+     *
+     * @param reg register location to start writing into
+     * @param buffer buffer for data storage
+     * @param len number of bytes to write
+     * @return mraa_result_t
+     */
+    mraa_result_t writeBytes(uint8_t reg, uint8_t *buffer, unsigned int len);
+
+    /**
+     * Read value(s) from registers
+     *
+     * @param reg register location to start reading from
+     * @param buffer buffer for data storage
+     * @param len number of bytes to read
+     */
+    void readBytes(uint8_t reg, uint8_t *buffer, unsigned int len);
+
+    /**
+     * button states
+     */
+    uint16_t m_buttonStates;
+
+    /**
+     * Over current fault detected
+     */
+    bool m_overCurrentFault;
+
+  private:
+    mraa_i2c_context m_i2c;
+    uint8_t m_addr;
+  };
+}
+
+