fix(wire): ensure i2c bus is ready

Previously, i2c_master_write and i2c_master_read returned I2C_OK if
first HAL call returned HAL_BUSY which was not correct.
Now make sure the i2c is ready, which guarantees a good
initialization of the read or write sequence.

Fixes stm32duino#1774

Signed-off-by: Frederic Pillon <[email protected]>

Author: fpistm

libraries/Wire/src/utility/twi.c

@@ -848,6 +848,7 @@ i2c_status_e i2c_master_write(i2c_t *obj, uint8_t dev_address,
   uint32_t tickstart = HAL_GetTick();
   uint32_t delta = 0;
   uint32_t err = 0;
+  HAL_StatusTypeDef status = HAL_OK;
 
   /* When size is 0, this is usually an I2C scan / ping to check if device is there and ready */
   if (size == 0) {
@@ -856,12 +857,26 @@ i2c_status_e i2c_master_write(i2c_t *obj, uint8_t dev_address,
 #if defined(I2C_OTHER_FRAME)
     uint32_t XferOptions = obj->handle.XferOptions; // save XferOptions value, because handle can be modified by HAL, which cause issue in case of NACK from slave
 #endif
-
+    do {
 #if defined(I2C_OTHER_FRAME)
-    if (HAL_I2C_Master_Seq_Transmit_IT(&(obj->handle), dev_address, data, size, XferOptions) == HAL_OK) {
+      status = HAL_I2C_Master_Seq_Transmit_IT(&(obj->handle), dev_address, data, size, XferOptions);
 #else
-    if (HAL_I2C_Master_Transmit_IT(&(obj->handle), dev_address, data, size) == HAL_OK) {
+      status = HAL_I2C_Master_Transmit_IT(&(obj->handle), dev_address, data, size);
 #endif
+      // Ensure i2c ready
+      if (status == HAL_BUSY) {
+        delta = (HAL_GetTick() - tickstart);
+        if (delta > I2C_TIMEOUT_TICK) {
+          ret = I2C_BUSY;
+          break;
+        }
+      } else {
+        ret = (status == HAL_OK) ? I2C_OK : I2C_ERROR;
+      }
+    } while (status == HAL_BUSY);
+
+    if (ret == I2C_OK) {
+      tickstart = HAL_GetTick();
       // wait for transfer completion
       while ((HAL_I2C_GetState(&(obj->handle)) != HAL_I2C_STATE_READY) && (delta < I2C_TIMEOUT_TICK)) {
         delta = (HAL_GetTick() - tickstart);
@@ -926,16 +941,31 @@ i2c_status_e i2c_master_read(i2c_t *obj, uint8_t dev_address, uint8_t *data, uin
   uint32_t tickstart = HAL_GetTick();
   uint32_t delta = 0;
   uint32_t err = 0;
+  HAL_StatusTypeDef status = HAL_OK;
 
 #if defined(I2C_OTHER_FRAME)
   uint32_t XferOptions = obj->handle.XferOptions; // save XferOptions value, because handle can be modified by HAL, which cause issue in case of NACK from slave
 #endif
-
+  do {
 #if defined(I2C_OTHER_FRAME)
-  if (HAL_I2C_Master_Seq_Receive_IT(&(obj->handle), dev_address, data, size, XferOptions) == HAL_OK) {
+    status = HAL_I2C_Master_Seq_Receive_IT(&(obj->handle), dev_address, data, size, XferOptions);
 #else
-  if (HAL_I2C_Master_Receive_IT(&(obj->handle), dev_address, data, size) == HAL_OK) {
+    status = HAL_I2C_Master_Receive_IT(&(obj->handle), dev_address, data, size);
 #endif
+    // Ensure i2c ready
+    if (status == HAL_BUSY) {
+      delta = (HAL_GetTick() - tickstart);
+      if (delta > I2C_TIMEOUT_TICK) {
+        ret = I2C_BUSY;
+        break;
+      }
+    } else {
+      ret = (status == HAL_OK) ? I2C_OK : I2C_ERROR;
+    }
+  } while (status == HAL_BUSY);
+
+  if (ret == I2C_OK) {
+    tickstart = HAL_GetTick();
     // wait for transfer completion
     while ((HAL_I2C_GetState(&(obj->handle)) != HAL_I2C_STATE_READY) && (delta < I2C_TIMEOUT_TICK)) {
       delta = (HAL_GetTick() - tickstart);