mlx90614: added new sensor (ir temperature), there is an issue with repeated start bit in i2c thus the sensor return incorrect data

Signed-off-by: Kiveisha Yevgeniy <yevgeniy.kiveisha@intel.com>

src/mlx90614/mlx90614.cxx

@@ -0,0 +1,129 @@
+/*
+ * Author: Yevgeniy Kiveisha <yevgeniy.kiveisha@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 "mlx90614.h"
+
+using namespace upm;
+
+struct MLX90614Exception : public std::exception {
+    std::string message;
+    MLX90614Exception (std::string msg) : message (msg) { }
+    ~MLX90614Exception () throw () { }
+    const char* what() const throw () { return message.c_str(); }
+};
+
+MLX90614::MLX90614 (int bus, int devAddr) {
+    m_name = "MLX90614";
+
+    m_i2cAddr = devAddr;
+    m_bus = bus;
+
+    m_i2Ctx = mraa_i2c_init(m_bus);
+
+    mraa_result_t ret = mraa_i2c_address(m_i2Ctx, m_i2cAddr);
+    if (ret != MRAA_SUCCESS) {
+        throw MLX90614Exception ("Couldn't initilize I2C.");
+    }
+}
+
+MLX90614::~MLX90614() {
+    mraa_i2c_stop(m_i2Ctx);
+}
+
+float
+MLX90614::readObjectTempF(void) {
+    return (readTemperature (MLX90614_TOBJ1) * 9 / 5) + 32;
+}
+
+float
+MLX90614::readAmbientTempF(void) {
+    return (readTemperature (MLX90614_TA) * 9 / 5) + 32;
+}
+
+float
+MLX90614::readObjectTempC(void) {
+    return readTemperature (MLX90614_TOBJ1);
+}
+
+float
+MLX90614::readAmbientTempC(void) {
+    return readTemperature (MLX90614_TA);
+}
+
+/*
+ * **************
+ *  private area
+ * **************
+ */
+uint16_t
+MLX90614::i2cReadReg_N (int reg, unsigned int len, uint8_t * buffer) {
+    int readByte = 0;
+
+    if (m_i2Ctx == NULL) {
+        throw MLX90614Exception ("Couldn't find initilized I2C.");
+    }
+
+    mraa_i2c_address(m_i2Ctx, m_i2cAddr);
+    mraa_i2c_write_byte(m_i2Ctx, reg);
+
+    readByte = mraa_i2c_read(m_i2Ctx, buffer, len);
+    return readByte;
+}
+
+mraa_result_t
+MLX90614::i2cWriteReg_N (uint8_t reg, unsigned int len, uint8_t * buffer) {
+    mraa_result_t error = MRAA_SUCCESS;
+
+    if (m_i2Ctx == NULL) {
+        throw MLX90614Exception ("Couldn't find initilized I2C.");
+    }
+
+    error = mraa_i2c_address (m_i2Ctx, m_i2cAddr);
+    error = mraa_i2c_write (m_i2Ctx, buffer, len);
+
+    return error;
+}
+
+float
+MLX90614::readTemperature (uint8_t address) {
+    uint8_t     buffer[3];
+    float       temperature = 0;
+
+    /*  Reading temperature from sensor.
+        Answer contained of 3 bytes (TEMP_LSB | TEMP_MSB | PEC)
+     */
+    if (i2cReadReg_N (address, 3, buffer) > 2) {
+        temperature = buffer[0];
+        temperature = buffer[1] << 8;
+
+        temperature *= .02;
+        temperature -= 273.15;
+    }
+
+    return temperature;
+}