[HAL][SMBUS] Update HAL SMBUS driver to prefetch data before starting the transmission: implementation of errata sheet workaround I2C2-190208 : Transmission stalled after first byte

Src/stm32f0xx_hal_smbus.c

diff --git a/Src/stm32f0xx_hal_smbus.c b/Src/stm32f0xx_hal_smbus.c
index bca284c..f871857 100644
--- a/Src/stm32f0xx_hal_smbus.c
+++ b/Src/stm32f0xx_hal_smbus.c
@@ -926,6 +926,7 @@
                                                uint8_t *pData, uint16_t Size, uint32_t XferOptions)
 {
   uint32_t tmp;
+  uint32_t sizetoxfer = 0U;
 
   /* Check the parameters */
   assert_param(IS_SMBUS_TRANSFER_OPTIONS_REQUEST(XferOptions));
@@ -958,11 +959,28 @@
       hsmbus->XferSize = Size;
     }
 
+    sizetoxfer = hsmbus->XferSize;
+    if ((hsmbus->XferSize > 0U) && ((XferOptions == SMBUS_FIRST_FRAME) ||
+                                    (XferOptions == SMBUS_FIRST_AND_LAST_FRAME_NO_PEC) ||
+                                    (XferOptions == SMBUS_FIRST_FRAME_WITH_PEC) ||
+                                    (XferOptions == SMBUS_FIRST_AND_LAST_FRAME_WITH_PEC)))
+    {
+      /* Preload TX register */
+      /* Write data to TXDR */
+      hsmbus->Instance->TXDR = *hsmbus->pBuffPtr;
+
+      /* Increment Buffer pointer */
+      hsmbus->pBuffPtr++;
+
+      hsmbus->XferCount--;
+      hsmbus->XferSize--;
+    }
+
     /* Send Slave Address */
     /* Set NBYTES to write and reload if size > MAX_NBYTE_SIZE and generate RESTART */
-    if ((hsmbus->XferSize < hsmbus->XferCount) && (hsmbus->XferSize == MAX_NBYTE_SIZE))
+    if ((sizetoxfer < hsmbus->XferCount) && (sizetoxfer == MAX_NBYTE_SIZE))
     {
-      SMBUS_TransferConfig(hsmbus, DevAddress, (uint8_t)hsmbus->XferSize,
+      SMBUS_TransferConfig(hsmbus, DevAddress, (uint8_t)sizetoxfer,
                            SMBUS_RELOAD_MODE | (hsmbus->XferOptions & SMBUS_SENDPEC_MODE),
                            SMBUS_GENERATE_START_WRITE);
     }
@@ -977,7 +995,7 @@
       if ((hsmbus->PreviousState == HAL_SMBUS_STATE_MASTER_BUSY_TX) && \
           (IS_SMBUS_TRANSFER_OTHER_OPTIONS_REQUEST(tmp) == 0))
       {
-        SMBUS_TransferConfig(hsmbus, DevAddress, (uint8_t)hsmbus->XferSize, hsmbus->XferOptions,
+        SMBUS_TransferConfig(hsmbus, DevAddress, (uint8_t)sizetoxfer, hsmbus->XferOptions,
                              SMBUS_NO_STARTSTOP);
       }
       /* Else transfer direction change, so generate Restart with new transfer direction */
@@ -987,7 +1005,7 @@
         SMBUS_ConvertOtherXferOptions(hsmbus);
 
         /* Handle Transfer */
-        SMBUS_TransferConfig(hsmbus, DevAddress, (uint8_t)hsmbus->XferSize,
+        SMBUS_TransferConfig(hsmbus, DevAddress, (uint8_t)sizetoxfer,
                              hsmbus->XferOptions,
                              SMBUS_GENERATE_START_WRITE);
       }