DS2413: Add string based constructor for Switch

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

src/ds2413/ds2413.cxx

@@ -27,6 +27,8 @@
 #include <stdexcept>
 
 #include "ds2413.hpp"
+#include "upm_string_parser.hpp"
+
 
 using namespace upm;
 using namespace std;
@@ -48,6 +50,39 @@ DS2413::DS2413(int uart) :
     }
 }
 
+DS2413::DS2413(std::string initStr) : m_uart(nullptr), mraaIo(initStr)
+{
+  mraa_io_descriptor* descs = mraaIo.getMraaDescriptors();
+  std::vector<std::string> upmTokens;
+  
+  if(!mraaIo.getLeftoverStr().empty()) {
+    upmTokens = UpmStringParser::parse(mraaIo.getLeftoverStr());
+  }
+  
+  m_uart = descs->uart_ows[0];
+  m_devicesFound = 0;
+
+  // check basic access to the 1-wire bus (presence detect)
+  mraa::Result rv;
+
+  if ((rv = m_uart.reset()) != mraa::SUCCESS)
+  {
+    throw std::runtime_error(std::string(__FUNCTION__) +
+                              ": reset() failed, no devices on bus?");
+    return;
+  }
+  
+  for(std::string tok : upmTokens) {
+    if(tok.substr(0, 11) == "writeGpios:") {
+      std::string::size_type sz;
+      int index = std::stoi(tok.substr(11), &sz);
+      tok = tok.substr(11);
+      int value = std::stoi(tok.substr(sz+1), nullptr, 0);
+      writeGpios(index, value);
+    }
+  }
+}
+
 DS2413::~DS2413()
 {
 }

src/ds2413/ds2413.hpp

@@ -26,6 +26,7 @@
 #include <string>
 #include <iostream>
 #include <map>
+#include <vector>
 
 #include <stdlib.h>
 #include <unistd.h>
@@ -33,6 +34,7 @@
 
 #include <mraa/common.hpp>
 #include <mraa/uart_ow.hpp>
+#include <mraa/initio.hpp>
 
 #define DS2413_DEFAULT_UART 0
 
@@ -100,6 +102,13 @@ namespace upm {
      */
     DS2413(int uart=DS2413_DEFAULT_UART);
 
+    /**
+     * Instantiates DS2413 Switch object based on a given string.
+     *
+     * @param initStr string containing specific information for DS2413 Switch initialization.
+     */
+    DS2413(std::string initStr); 
+    
     /**
      * DS2413 object destructor
      */
@@ -164,6 +173,7 @@ namespace upm {
 
   protected:
     mraa::UartOW m_uart;
+    mraa::MraaIo mraaIo;
     
     // the total number of devices found
     int m_devicesFound;