Add smbus support and the writeQuick function (#43)

Author: jp-bennett

ArduinoCore-API/api/HardwareI2C.h

@@ -41,6 +41,8 @@ class HardwareI2C : public Stream
 
     virtual void onReceive(void(*)(int)) = 0;
     virtual void onRequest(void(*)(void)) = 0;
+
+    virtual int writeQuick(uint8_t toWrite) = 0;
 };
 
 }

cores/portduino/linux/LinuxHardwareI2C.cpp

@@ -9,6 +9,14 @@
 #include <iostream>
 #include <linux/i2c.h>
 
+
+extern "C"
+{
+    #include<linux/i2c-dev.h>
+    #include <i2c/smbus.h>
+}
+
+
 namespace arduino {
     char buf[100] = {0};
     int requestedBytes = 0;
@@ -46,6 +54,10 @@ namespace arduino {
 
     }
 
+    int LinuxHardwareI2C::writeQuick(uint8_t toWrite) {
+        int a = i2c_smbus_write_quick(i2c_file, toWrite);
+        return a;
+    }
 
     size_t LinuxHardwareI2C::write(uint8_t toWrite) {
         buf[requestedBytes] = toWrite; // todo: alloc and copy

cores/portduino/linux/LinuxHardwareI2C.h

@@ -53,6 +53,8 @@ class LinuxHardwareI2C : public HardwareI2C {
   // Methods from Print
 
   virtual size_t write(uint8_t toWrite);
+  
+  int writeQuick(uint8_t toWrite);
 
   virtual size_t write(const uint8_t *buffer, size_t size);
 

cores/portduino/simulated/SimHardwareI2C.h

@@ -22,6 +22,7 @@ enum ResultI2c {
 class SimHardwareI2C : public HardwareI2C {
 public:
   virtual void begin() NOT_IMPLEMENTED("i2cbegin");
+  virtual int writeQuick(uint8_t toWrite) NOT_IMPLEMENTED("writeQuick");
 
   virtual void begin(uint8_t address) NOT_IMPLEMENTED("i2cslave begin");