max44009: Initial Implementation Maxim 44009 light sensor

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Abhishek Malik <abhishek.malik@intel.com>

src/max44009/max44009.cxx

@@ -0,0 +1,99 @@
+/*
+ * Author: Scott Ware <scott.r.ware@intel.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.
+ */
+
+#include <iostream>
+#include <unistd.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include "max44009.h"
+
+using namespace upm;
+
+MAX44009::MAX44009 (int bus, int devAddr) {
+
+    m_maxControlAddr = devAddr;
+    i2c = new mraa::I2c(bus);
+    i2c->address(m_maxControlAddr);
+
+    // Reset chip to defaults
+    status = mraa::SUCCESS;
+    reset();
+    if (!isConfigured())
+        UPM_THROW("config failure");
+}
+
+MAX44009::~MAX44009() {
+    delete i2c;
+}
+
+mraa::Result
+MAX44009::reset() {
+    uint8_t address[5] = {MAX44009_INT_ENABLE_ADDR, MAX44009_CONFIG_ADDR, \
+                                   MAX44009_THR_HIGH_ADDR, MAX44009_THR_LOW_ADDR, \
+                                   MAX44009_THR_TIMER_ADDR};
+    uint8_t value[5]   = {MAX44009_INT_DISABLED, MAX44009_DEFAULT_CONFIGURATION, \
+                                   0xFF, 0x00, 0xFF};
+    uint8_t i;
+    for (i = 0; i < sizeof(address) && status == mraa::SUCCESS; i++) {
+        status = i2c->writeReg(address[i], value[i]);
+    }
+    return status;
+}
+
+uint16_t
+MAX44009::getVisibleRaw() {
+    uint8_t exponent, mantissa;
+    uint8_t data[MAX44009_LUX_LENGTH];
+    uint16_t* value = reinterpret_cast<uint16_t*>(&data[0]);
+
+    int length = i2c->readBytesReg(MAX44009_LUX_START_ADDR, data, MAX44009_LUX_LENGTH);
+
+    if(length != MAX44009_LUX_LENGTH)
+        UPM_THROW("Read error");
+
+    return *value;
+}
+
+
+double
+MAX44009::getVisibleLux() {
+    uint16_t rawValue = getVisibleRaw();
+    uint8_t rawValueMsb = rawValue >> 8;
+    uint8_t rawValueLsb = rawValue & 0xFF;    
+    uint8_t exponent = (( rawValueMsb & 0xF0 ) >> 4);
+    uint8_t mantissa = (( rawValueMsb & 0x0F ) << 4 ) | ( rawValueLsb & 0x0F );
+
+    // Check for overrange condition
+    if(exponent == MAX44009_OVERRANGE_CONDITION) 
+        UPM_THROW("Overrange error");        
+
+    return pow((double)2,(double)exponent) * mantissa * 0.045;
+}
+
+
+bool
+MAX44009::isConfigured() {
+    return  status == mraa::SUCCESS;
+}