Bugfix for HardWire/I2C + configured/compiled dfu-util to work on Linux again

- Fixed 0 byte payload bug, stopping HardWire from sending only addresses to scan for devices
 - Fixed I2C bug accessing wrong status register for error flags
 - Improved Hardwire endTransmission() return flags to correspond with the actual I2C failure status
 - Removed dos endings from dfu-util autogen script breaking compilation

STM32F1/cores/maple/libmaple/i2c.c

@@ -235,7 +235,7 @@ int32 i2c_master_xfer(i2c_dev *dev,
 
     i2c_enable_irq(dev, I2C_IRQ_EVENT);
     i2c_start_condition(dev);
-
+    
     rc = wait_for_state_change(dev, I2C_STATE_XFER_DONE, timeout);
     if (rc < 0) {
         goto out;
@@ -347,9 +347,20 @@ void _i2c_irq_handler(i2c_dev *dev) {
              * register.  We should get another TXE interrupt
              * immediately to fill DR again.
              */
-            if (msg->length != 1) {
+            if (msg->length > 1) {
                 i2c_write(dev, msg->data[msg->xferred++]);
-            }
+            } else if (msg->length == 0){ /* We're just sending an address */
+                i2c_stop_condition(dev);
+              /*
+               * Turn off event interrupts to keep BTF from firing until
+               * the end of the stop condition. Why on earth they didn't
+               * have a start/stop condition request clear BTF is beyond
+               * me.
+               */
+              i2c_disable_irq(dev, I2C_IRQ_EVENT);
+              I2C_CRUMB(STOP_SENT, 0, 0);
+              dev->state = I2C_STATE_XFER_DONE;
+            } /* else we're just sending one byte */
         }
         sr1 = sr2 = 0;
     }
@@ -456,7 +467,7 @@ void _i2c_irq_handler(i2c_dev *dev) {
 void _i2c_irq_error_handler(i2c_dev *dev) {
     I2C_CRUMB(ERROR_ENTRY, dev->regs->SR1, dev->regs->SR2);
 
-    dev->error_flags = dev->regs->SR2 & (I2C_SR1_BERR |
+    dev->error_flags = dev->regs->SR1 & (I2C_SR1_BERR |
                                          I2C_SR1_ARLO |
                                          I2C_SR1_AF |
                                          I2C_SR1_OVR);

STM32F1/libraries/Wire/HardWire.cpp

@@ -40,11 +40,16 @@
 
 uint8 HardWire::process() {
     int8 res = i2c_master_xfer(sel_hard, &itc_msg, 1, 0);
-    if (res != 0) {
+    if (res == I2C_ERROR_PROTOCOL) {
+        if (sel_hard->error_flags & I2C_SR1_AF)
+            res = (sel_hard->error_flags & I2C_SR1_ADDR ? ENACKADDR : 
+                                                           ENACKTRNS);
+        else if (sel_hard->error_flags & I2C_SR1_OVR) res = EDATA;
+        else res = EOTHER;
         i2c_disable(sel_hard);
         i2c_master_enable(sel_hard, (I2C_BUS_RESET | dev_flags));
     }
-    return 0;
+    return res;
 }
 
 // TODO: Add in Error Handling if devsel is out of range for other Maples
@@ -56,7 +61,7 @@ HardWire::HardWire(uint8 dev_sel, uint8 flags) {
     } else {
         ASSERT(1);
     }
-    dev_flags=flags;
+    dev_flags = flags;
 }
 
 HardWire::~HardWire() {

STM32F1/libraries/Wire/HardWire.h

@@ -67,5 +67,5 @@ public:
 
     void begin(uint8 = 0x00);
 };
-
+extern HardWire HWire;
 #endif // _HARDWIRE_H_

STM32F1/libraries/Wire/WireBase.cpp

@@ -61,11 +61,10 @@ void WireBase::beginTransmission(int slave_address) {
 
 uint8 WireBase::endTransmission(void) {
     uint8 retVal;
-	
-	if (tx_buf_overflow) {
+    if (tx_buf_overflow) {
         return EDATA;
     }
-    retVal=process();// Changed so that the return value from process is returned by this function see also the return line below
+    retVal = process();// Changed so that the return value from process is returned by this function see also the return line below
     tx_buf_idx = 0;
     tx_buf_overflow = false;
     return retVal;//SUCCESS;

tools/src/dfu-util/autogen.sh

@@ -1,2 +1,2 @@
-#! /bin/sh
-autoreconf -v -i
+#! /bin/sh
+autoreconf -v -i