AT42QT1070: Add string based constructor for QTouch

Signed-off-by: Adelin Dobre <adelin.dobre@rinftech.com>

src/at42qt1070/at42qt1070.cxx

@@ -62,6 +62,32 @@ AT42QT1070::AT42QT1070(int bus, uint8_t address)
     m_overflow = false;
 }
 
+AT42QT1070::AT42QT1070(std::string initStr) : mraaIo(initStr)
+{
+    mraa_io_descriptor* descs = mraaIo.getMraaDescriptors();
+
+    if(!descs->i2cs) {
+      throw std::invalid_argument(std::string(__FUNCTION__) +
+                                    ": mraa_i2c_init() failed");
+    }
+    else {
+      if( !(m_i2c = descs->i2cs[0]) ) {
+        throw std::invalid_argument(std::string(__FUNCTION__) +
+                                ": mraa_i2c_init() failed");
+
+      }
+    }
+
+    if (readChipID() != 0x2E) {
+        throw std::runtime_error("Chip ID does not match the expected value (2Eh)");
+    }
+
+    m_buttonStates = 0;
+    m_calibrating = false;
+    m_overflow = false;
+
+}
+
 AT42QT1070::~AT42QT1070()
 {
     mraa_i2c_stop(m_i2c);

src/at42qt1070/at42qt1070.hpp

@@ -28,6 +28,7 @@
 
 #include <string>
 #include <mraa/i2c.h>
+#include <mraa/initio.hpp>
 
 #define AT42QT1070_I2C_BUS 0
 #define AT42QT1070_DEFAULT_I2C_ADDR 0x1b
@@ -149,6 +150,13 @@ class AT42QT1070
      */
     AT42QT1070(int bus, uint8_t address = AT42QT1070_DEFAULT_I2C_ADDR);
 
+    /**
+     * Instantiates AT42QT1070 QTouch Sensor based on a given string.
+     *
+     * @param initStr string containing specific information for AT42QT1070 initialization.
+     */
+    AT42QT1070(std::string initStr);
+
     /**
      * AT42QT1070 destructor
      */
@@ -309,6 +317,7 @@ class AT42QT1070
     bool m_overflow;
 
     mraa_i2c_context m_i2c;
+    mraa::MraaIo mraaIo;
     uint8_t m_addr;
 };
 }