drivers: i2c_ll_stm32_v2: don't use while loops in interrupt mode

Waiting for transfer complete and stop condition uses while loops
even when interrupt mode is enabled.
Implement use of TC, TCR and STOP interrupt for interrupt mode.
msg_done is not needed in interrupt mode anymore, so move it
to non-interrupt section
Tested with stm32f3_disco board.

Signed-off-by: Daniel Wagenknecht <[email protected]>

Author: Daniel Wagenknecht

drivers/i2c/i2c_ll_stm32_v2.c

@@ -54,56 +54,68 @@ static inline void msg_init(struct device *dev, struct i2c_msg *msg,
 	}
 }
 
-static inline void msg_done(struct device *dev, unsigned int current_msg_flags)
-{
-	const struct i2c_stm32_config *cfg = DEV_CFG(dev);
-	I2C_TypeDef *i2c = cfg->i2c;
-
-	/* Wait for transfer to complete */
-	while (!LL_I2C_IsActiveFlag_TC(i2c) && !LL_I2C_IsActiveFlag_TCR(i2c)) {
-		;
-	}
-	/* Issue stop condition if necessary */
-	if (current_msg_flags & I2C_MSG_STOP) {
-		LL_I2C_GenerateStopCondition(i2c);
-		while (!LL_I2C_IsActiveFlag_STOP(i2c)) {
-			;
-		}
-		LL_I2C_ClearFlag_STOP(i2c);
-		LL_I2C_DisableReloadMode(i2c);
-	}
-}
-
 #ifdef CONFIG_I2C_STM32_INTERRUPT
 void stm32_i2c_event_isr(void *arg)
 {
 	const struct i2c_stm32_config *cfg = DEV_CFG((struct device *)arg);
 	struct i2c_stm32_data *data = DEV_DATA((struct device *)arg);
 	I2C_TypeDef *i2c = cfg->i2c;
 
-	if (data->current.is_write) {
-		if (data->current.len && LL_I2C_IsActiveFlag_TXIS(i2c)) {
+	if (data->current.len) {
+		/* Interrupts for sending/receiving next byte */
+
+		if (data->current.is_write && LL_I2C_IsActiveFlag_TXIS(i2c)) {
+			/* Send next byte */
 			LL_I2C_TransmitData8(i2c, *data->current.buf);
+		} else if (!(data->current.is_write) &&
+			   LL_I2C_IsActiveFlag_RXNE(i2c)) {
+			/* Receive next byte */
+			*data->current.buf = LL_I2C_ReceiveData8(i2c);
 		} else {
-			LL_I2C_DisableIT_TX(i2c);
 			goto error;
 		}
+
+		data->current.buf++;
+		data->current.len--;
+		if (!data->current.len) {
+			LL_I2C_EnableIT_TC(i2c);
+		}
+
 	} else {
-		if (data->current.len && LL_I2C_IsActiveFlag_RXNE(i2c)) {
-			*data->current.buf = LL_I2C_ReceiveData8(i2c);
+		/* Interrupts to process end of message */
+
+		if (LL_I2C_IsActiveFlag_TC(i2c) ||
+		    LL_I2C_IsActiveFlag_TCR(i2c)) {
+			/* Interrupt after last byte of message
+			 * was transferred
+			 */
+			LL_I2C_DisableIT_TC(i2c);
+
+			/* Issue stop condition if necessary */
+			if (data->current.msg->flags & I2C_MSG_STOP) {
+				LL_I2C_GenerateStopCondition(i2c);
+				LL_I2C_EnableIT_STOP(i2c);
+			} else {
+				k_sem_give(&data->device_sync_sem);
+			}
+
+		} else if (LL_I2C_IsActiveFlag_STOP(i2c)) {
+			/* Interrupt after stop condition was
+			 * successfully issued
+			 */
+			LL_I2C_DisableIT_STOP(i2c);
+			LL_I2C_ClearFlag_STOP(i2c);
+			LL_I2C_DisableReloadMode(i2c);
+			k_sem_give(&data->device_sync_sem);
 		} else {
-			LL_I2C_DisableIT_RX(i2c);
 			goto error;
 		}
 	}
 
-	data->current.buf++;
-	data->current.len--;
-	if (!data->current.len) {
-		k_sem_give(&data->device_sync_sem);
-	}
 	return;
 error:
+	LL_I2C_DisableIT_TX(i2c);
+	LL_I2C_DisableIT_RX(i2c);
 	data->current.is_err = 1;
 	k_sem_give(&data->device_sync_sem);
 }
@@ -136,6 +148,7 @@ int stm32_i2c_msg_write(struct device *dev, struct i2c_msg *msg,
 	data->current.is_write = 1;
 	data->current.is_nack = 0;
 	data->current.is_err = 0;
+	data->current.msg = msg;
 
 	msg_init(dev, msg, next_msg_flags, slave, LL_I2C_REQUEST_WRITE);
 	LL_I2C_EnableIT_TX(i2c);
@@ -149,8 +162,6 @@ int stm32_i2c_msg_write(struct device *dev, struct i2c_msg *msg,
 		goto error;
 	}
 
-	msg_done(dev, msg->flags);
-
 	return 0;
 error:
 	if (data->current.is_nack) {
@@ -178,6 +189,7 @@ int stm32_i2c_msg_read(struct device *dev, struct i2c_msg *msg,
 	data->current.buf = msg->buf;
 	data->current.is_write = 0;
 	data->current.is_err = 0;
+	data->current.msg = msg;
 
 	msg_init(dev, msg, next_msg_flags, slave, LL_I2C_REQUEST_READ);
 	LL_I2C_EnableIT_RX(i2c);
@@ -189,8 +201,6 @@ int stm32_i2c_msg_read(struct device *dev, struct i2c_msg *msg,
 		goto error;
 	}
 
-	msg_done(dev, msg->flags);
-
 	return 0;
 error:
 	SYS_LOG_DBG("%s: ERR %d", __func__, data->current.is_err);
@@ -200,6 +210,26 @@ int stm32_i2c_msg_read(struct device *dev, struct i2c_msg *msg,
 }
 
 #else /* !CONFIG_I2C_STM32_INTERRUPT */
+static inline void msg_done(struct device *dev, unsigned int current_msg_flags)
+{
+	const struct i2c_stm32_config *cfg = DEV_CFG(dev);
+	I2C_TypeDef *i2c = cfg->i2c;
+
+	/* Wait for transfer to complete */
+	while (!LL_I2C_IsActiveFlag_TC(i2c) && !LL_I2C_IsActiveFlag_TCR(i2c)) {
+		;
+	}
+	/* Issue stop condition if necessary */
+	if (current_msg_flags & I2C_MSG_STOP) {
+		LL_I2C_GenerateStopCondition(i2c);
+		while (!LL_I2C_IsActiveFlag_STOP(i2c)) {
+			;
+		}
+		LL_I2C_ClearFlag_STOP(i2c);
+		LL_I2C_DisableReloadMode(i2c);
+	}
+}
+
 int stm32_i2c_msg_write(struct device *dev, struct i2c_msg *msg,
 			u8_t *next_msg_flags, uint16_t slave)
 {