Wire ReSTART fix, with others (#1717)

* ReSTART fix, Sequencing fix

pr #1665 introduce a problem with ReSTART, when solving this problem I found an interaction between the TxFifo refill, RxFifo empty and CMD[] fill.  during certain sequences a dataqueue command would be skipped, this skipping resulted in a mismatch between the contents of the TxFifo and the i2c command sequence.  The problem manifested as an ACK error. 
In addition to this required bug fix I propose:
* `Wire.begin()` be changed from a `void` to a `bool` this will allow the reset functionality of `Wire.begin()` to be reported.  Currently `Wire.begin()` attempts to reset the i2c Peripheral, but cannot report success/failure.
* `Wire.busy()` be added. this `bool` function returns the hardware status of the bus. This status can be use in multi-master environments for application level interleaving of commands, also in single master environment, it can be used to detect a 'hung' bus.  With the functional change to `Wire.begin()` this allows app level recover of a hung bus.
* `Wire.lastError()` value updated for all errors, previously when interleaving `Wire.endTransmission(false)` and `Wire.readTransmission(false)`, the 128 byte `Wire.write()` buffer was exhausted without generating and error(very exotic). I discovered this error when I created a sequence of directed reads to a EEPROM. Each directed read used 2 bytes of the 128 byte `write()` buffer, so after 64 consecutive ReSTART writes with ReSTART reads, `Wire()`  had no room to record the directed address bytes.  It generated just a NAK check without setting the EEPROMs internal register address.  The succeeding ReSTART read succeeded at incorrect address.
* Changes to the HAL layer:
** added `i2cGetStatus()` which returns the i2c peripheral status word, used to detect bus_busy currently
** added `i2cDebug()` programmatic control of debug buffer output
** changed `i2cAddQueue()` to allow data_only queue element this will allow a i2c transaction to use multiple data pointers.
** removed direct access to DumpInts(), DumpI2c() from app, use i2cDebug() to set trigger points 
 
*

* Update esp32-hal-i2c.c

* Update Wire.cpp

* ReSTART, Sequencing

pr #1665 introduce a problem with ReSTART, when solving this problem I found an interaction between the TxFifo refill, RxFifo empty and CMD[] fill.  during certain sequences a dataqueue command would be skipped, this skipping resulted in a mismatch between the contents of the TxFifo and the i2c command sequence.  The problem manifested as an ACK error. 
In addition to this required bug fix I propose:
* `Wire.begin()` be changed from a `void` to a `bool` this will allow the reset functionality of `Wire.begin()` to be reported.  Currently `Wire.begin()` attempts to reset the i2c Peripheral, but cannot report success/failure.
* `Wire.busy()` be added. this `bool` function returns the hardware status of the bus. This status can be use in multi-master environments for application level interleaving of commands, also in single master environment, it can be used to detect a 'hung' bus.  With the functional change to `Wire.begin()` this allows app level recover of a hung bus.
* `Wire.lastError()` value updated for all errors, previously when interleaving `Wire.endTransmission(false)` and `Wire.readTransmission(false)`, the 128 byte `Wire.write()` buffer was exhausted without generating and error(very exotic). I discovered this error when I created a sequence of directed reads to a EEPROM. Each directed read used 2 bytes of the 128 byte `write()` buffer, so after 64 consecutive ReSTART writes with ReSTART reads, `Wire()`  had no room to record the directed address bytes.  It generated just a NAK check without setting the EEPROMs internal register address.  The succeeding ReSTART read succeeded at incorrect address.
* Changes to the HAL layer:
** added `i2cGetStatus()` which returns the i2c peripheral status word, used to detect bus_busy currently
** added `i2cDebug()` programmatic control of debug buffer output
** changed `i2cAddQueue()` to allow data_only queue element this will allow a i2c transaction to use multiple data pointers.
** removed direct access to DumpInts(), DumpI2c() from app, use i2cDebug() to set trigger points 
 
*

* Forgot DebugFlags Return

@andriyadi found this, total brain fade on my part.

libraries/Wire/src/Wire.cpp

@@ -58,7 +58,7 @@ TwoWire::~TwoWire()
     }
 }
 
-void TwoWire::begin(int sdaPin, int sclPin, uint32_t frequency)
+bool TwoWire::begin(int sdaPin, int sclPin, uint32_t frequency)
 {
     if(sdaPin < 0) { // default param passed
         if(num == 0) {
@@ -70,7 +70,7 @@ void TwoWire::begin(int sdaPin, int sclPin, uint32_t frequency)
         } else {
             if(sda==-1) {
                 log_e("no Default SDA Pin for Second Peripheral");
-                return; //no Default pin for Second Peripheral
+                return false; //no Default pin for Second Peripheral
             } else {
                 sdaPin = sda;    // reuse prior pin
             }
@@ -87,7 +87,7 @@ void TwoWire::begin(int sdaPin, int sclPin, uint32_t frequency)
         } else {
             if(scl == -1) {
                 log_e("no Default SCL Pin for Second Peripheral");
-                return; //no Default pin for Second Peripheral
+                return false; //no Default pin for Second Peripheral
             } else {
                 sclPin = scl;    // reuse prior pin
             }
@@ -98,10 +98,11 @@ void TwoWire::begin(int sdaPin, int sclPin, uint32_t frequency)
     scl = sclPin;
     i2c = i2cInit(num, sdaPin, sclPin, frequency);
     if(!i2c) {
-        return;
+        return false;
     }
 
     flush();
+    return true;
 
 }
 
@@ -145,6 +146,7 @@ void TwoWire::beginTransmission(uint16_t address)
     txAddress = address;
     txIndex = txQueued; // allow multiple beginTransmission(),write(),endTransmission(false) until endTransmission(true)
     txLength = txQueued;
+    last_error = I2C_ERROR_OK;
 }
 
 /*stickbreaker isr
@@ -202,6 +204,7 @@ size_t TwoWire::write(uint8_t data)
 {
     if(transmitting) {
         if(txLength >= I2C_BUFFER_LENGTH) {
+            last_error = I2C_ERROR_MEMORY;
             return 0;
         }
         txBuffer[txIndex] = data;
@@ -209,20 +212,19 @@ size_t TwoWire::write(uint8_t data)
         txLength = txIndex;
         return 1;
     }
+    last_error = I2C_ERROR_NO_BEGIN; // no begin, not transmitting
     return 0;
 }
 
 size_t TwoWire::write(const uint8_t *data, size_t quantity)
 {
-    if(transmitting) {
-        for(size_t i = 0; i < quantity; ++i) {
-            if(!write(data[i])) {
-                return i;
-            }
+    for(size_t i = 0; i < quantity; ++i) {
+        if(!write(data[i])) {
+            return i;
         }
-        return quantity;
     }
-    return 0;
+    return quantity;
+
 }
 
 int TwoWire::available(void)
@@ -353,14 +355,13 @@ char * TwoWire::getErrorText(uint8_t err)
 
 /*stickbreaker Dump i2c Interrupt buffer, i2c isr Debugging
  */
-void TwoWire::dumpInts()
-{
-    i2cDumpInts(num);
+ 
+uint32_t TwoWire::setDebugFlags( uint32_t setBits, uint32_t resetBits){
+  return i2cDebug(i2c,setBits,resetBits);
 }
 
-void TwoWire::dumpI2C()
-{
-    i2cDumpI2c(i2c);
+bool TwoWire::busy(void){
+  return ((i2cGetStatus(i2c) & 16 )==16);
 }
 
 TwoWire Wire = TwoWire(0);