Add separate flags for I2C slave transfer in progress

Fixes ARMmbed#15498

Adds 2 boolean flags to the STM32 `i2c_s` object
to indicate whether a transfer is in progress,
separate from the existing "transfer pending" flags.

`i2c_slave_write`, `i2c_slave_read` and their associated callbacks
are modified to use these flags in addition to the pending flags.
The original behavior of the pending flags is preserved.

targets/TARGET_STM/TARGET_STM32F1/objects.h

@@ -99,6 +99,8 @@ struct i2c_s {
     uint8_t slave;
     volatile uint8_t pending_slave_tx_master_rx;
     volatile uint8_t pending_slave_rx_maxter_tx;
+    volatile uint8_t slave_tx_transfer_in_progress;
+    volatile uint8_t slave_rx_transfer_in_progress;
     uint8_t *slave_rx_buffer;
     volatile uint16_t slave_rx_buffer_size;
     volatile uint16_t slave_rx_count;

targets/TARGET_STM/TARGET_STM32F2/objects.h

@@ -114,6 +114,8 @@ struct i2c_s {
     uint8_t slave;
     volatile uint8_t pending_slave_tx_master_rx;
     volatile uint8_t pending_slave_rx_maxter_tx;
+    volatile uint8_t slave_tx_transfer_in_progress;
+    volatile uint8_t slave_rx_transfer_in_progress;
     uint8_t *slave_rx_buffer;
     volatile uint16_t slave_rx_buffer_size;
     volatile uint16_t slave_rx_count;

targets/TARGET_STM/TARGET_STM32F4/objects.h

@@ -88,6 +88,8 @@ struct i2c_s {
     uint8_t slave;
     volatile uint8_t pending_slave_tx_master_rx;
     volatile uint8_t pending_slave_rx_maxter_tx;
+    volatile uint8_t slave_tx_transfer_in_progress;
+    volatile uint8_t slave_rx_transfer_in_progress;
     uint8_t *slave_rx_buffer;
     volatile uint16_t slave_rx_buffer_size;
     volatile uint16_t slave_rx_count;

targets/TARGET_STM/TARGET_STM32L1/objects.h

@@ -85,6 +85,8 @@ struct i2c_s {
     uint8_t slave;
     volatile uint8_t pending_slave_tx_master_rx;
     volatile uint8_t pending_slave_rx_maxter_tx;
+    volatile uint8_t slave_tx_transfer_in_progress;
+    volatile uint8_t slave_rx_transfer_in_progress;
     uint8_t *slave_rx_buffer;
     volatile uint16_t slave_rx_buffer_size;
     volatile uint16_t slave_rx_count;

targets/TARGET_STM/i2c_api.c

@@ -563,6 +563,8 @@ void i2c_init_internal(i2c_t *obj, const i2c_pinmap_t *pinmap)
     obj_s->slave = 0;
     obj_s->pending_slave_tx_master_rx = 0;
     obj_s->pending_slave_rx_maxter_tx = 0;
+    obj_s->slave_tx_transfer_in_progress = 0;
+    obj_s->slave_rx_transfer_in_progress = 0;
 #endif
 
     obj_s->event = 0;
@@ -1618,6 +1620,7 @@ void HAL_I2C_SlaveTxCpltCallback(I2C_HandleTypeDef *I2cHandle)
     i2c_t *obj = get_i2c_obj(I2cHandle);
     struct i2c_s *obj_s = I2C_S(obj);
     obj_s->pending_slave_tx_master_rx = 0;
+    obj_s->slave_tx_transfer_in_progress = 0;
 }
 
 void HAL_I2C_SlaveRxCpltCallback(I2C_HandleTypeDef *I2cHandle)
@@ -1632,9 +1635,11 @@ void HAL_I2C_SlaveRxCpltCallback(I2C_HandleTypeDef *I2cHandle)
             HAL_I2C_Slave_Seq_Receive_IT(I2cHandle, &(obj_s->slave_rx_buffer[obj_s->slave_rx_count]), 1, I2C_NEXT_FRAME);
         } else {
             obj_s->pending_slave_rx_maxter_tx = 0;
+            obj_s->slave_rx_transfer_in_progress = 0;
         }
     } else {
         obj_s->pending_slave_rx_maxter_tx = 0;
+        obj_s->slave_rx_transfer_in_progress = 0;
     }
 }
 
@@ -1688,12 +1693,13 @@ int i2c_slave_read(i2c_t *obj, char *data, int length)
         _length = length;
     }
 
+    obj_s->slave_rx_transfer_in_progress = 1;
     /*  Always use I2C_NEXT_FRAME as slave will just adapt to master requests */
     ret = HAL_I2C_Slave_Seq_Receive_IT(handle, (uint8_t *) data, _length, I2C_NEXT_FRAME);
 
     if (ret == HAL_OK) {
         timeout = BYTE_TIMEOUT_US * (_length + 1);
-        while (obj_s->pending_slave_rx_maxter_tx && (--timeout != 0)) {
+        while (obj_s->slave_rx_transfer_in_progress && (--timeout != 0)) {
             wait_us(1);
         }
 
@@ -1718,12 +1724,13 @@ int i2c_slave_write(i2c_t *obj, const char *data, int length)
     int ret = 0;
     uint32_t timeout = 0;
 
+    obj_s->slave_tx_transfer_in_progress = 1;
     /*  Always use I2C_NEXT_FRAME as slave will just adapt to master requests */
     ret = HAL_I2C_Slave_Seq_Transmit_IT(handle, (uint8_t *) data, length, I2C_NEXT_FRAME);
 
     if (ret == HAL_OK) {
         timeout = BYTE_TIMEOUT_US * (length + 1);
-        while (obj_s->pending_slave_tx_master_rx && (--timeout != 0)) {
+        while (obj_s->slave_tx_transfer_in_progress && (--timeout != 0)) {
             wait_us(1);
         }
 

targets/TARGET_STM/stm_i2c_api.h

@@ -68,6 +68,8 @@ struct i2c_s {
     uint8_t slave;
     volatile uint8_t pending_slave_tx_master_rx;
     volatile uint8_t pending_slave_rx_maxter_tx;
+    volatile uint8_t slave_tx_transfer_in_progress;
+    volatile uint8_t slave_rx_transfer_in_progress;
     uint8_t *slave_rx_buffer;
     volatile uint16_t slave_rx_buffer_size;
     volatile uint16_t slave_rx_count;