Add Wire:setPins(sda, scl)

Fixes: #3779

Author: me-no-dev

Diff for: libraries/Wire/src/Wire.cpp

@@ -58,6 +58,17 @@ TwoWire::~TwoWire()
     }
 }
 
+bool TwoWire::setPins(int sdaPin, int sclPin)
+{
+    if(i2c) {
+        log_e("can not set pins if begin was already called");
+        return false;
+    }
+    sda = sdaPin;
+    scl = sclPin;
+    return true;
+}
+
 bool TwoWire::begin(int sdaPin, int sclPin, uint32_t frequency)
 {
     if(sdaPin < 0) { // default param passed

Diff for: libraries/Wire/src/Wire.h

@@ -67,6 +67,10 @@ class TwoWire: public Stream
 public:
     TwoWire(uint8_t bus_num);
     ~TwoWire();
+    
+    //call setPins() first, so that begin() can be called without arguments from libraries
+    bool setPins(int sda, int scl);
+    
     bool begin(int sda=-1, int scl=-1, uint32_t frequency=0); // returns true, if successful init of i2c bus
       // calling will attemp to recover hung bus