drivers: i2s : enable rx path and correct TRIGGER_DRAIN

In i2s_stm32_isr, remove the errors from SR register
   i2s_stm32_configure, enable the rx path for H7 I2S compatible IP

Correction of the handling of Tx audio samples via DMA

Signed-off-by: Franck Thebault <franck.thebault@st.com>
Signed-off-by: IBEN EL HADJ MESSAOUD Marwa <marwa.ibenelhadjmessaoud-ext@st.con>

drivers/i2s/i2s_ll_stm32.c

@@ -174,9 +174,6 @@ static int i2s_stm32_configure(const struct device *dev, enum i2s_dir dir,
 	int ret;
 
 	if (dir == I2S_DIR_RX) {
-#if DT_HAS_COMPAT_STATUS_OKAY(st_stm32h7_i2s)
-		return -ENOSYS;
-#endif
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
@@ -349,9 +346,20 @@ static int i2s_stm32_trigger(const struct device *dev, enum i2s_dir dir,
 			LOG_ERR("DRAIN trigger: invalid state");
 			return -EIO;
 		}
-		stream->stream_disable(stream, dev);
-		stream->queue_drop(stream);
-		stream->state = I2S_STATE_READY;
+		if (dir == I2S_DIR_TX) {
+			if (stream->state == I2S_STATE_RUNNING) {
+				stream->state = I2S_STATE_STOPPING;
+				/*
+				 * Indicate that the transition to I2S_STATE_STOPPING
+				 * is triggered by DRAIN command
+				 */
+				stream->sample_tx_stop_drain = true;
+			} else {
+				stream->stream_disable(stream, dev);
+				stream->queue_drop(stream);
+				stream->state = I2S_STATE_READY;
+			}
+		}
 		irq_unlock(key);
 		break;
 
@@ -529,6 +537,16 @@ static void dma_rx_callback(const struct device *dma_dev, void *arg,
 
 	mblk_tmp = stream->mem_block;
 
+	if ((stream->state == I2S_STATE_STOPPING) && (status == DMA_STATUS_COMPLETE)) {
+		if (stream->sample_tx_stop_drain == false) {
+			/*
+			 * In case of STOP command, just stop the transmission
+			 * at the current. The transmission can be resumed
+			 */
+			goto rx_handle_block;
+		}
+	}
+
 	/* Prepare to receive the next data block */
 	ret = k_mem_slab_alloc(stream->cfg.mem_slab, &stream->mem_block,
 			       K_NO_WAIT);
@@ -551,6 +569,7 @@ static void dma_rx_callback(const struct device *dma_dev, void *arg,
 		goto rx_disable;
 	}
 
+rx_handle_block:
 	/* Assure cache coherency after DMA write operation */
 	sys_cache_data_invd_range(mblk_tmp, stream->cfg.block_size);
 
@@ -597,12 +616,41 @@ static void dma_tx_callback(const struct device *dma_dev, void *arg,
 	k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 	stream->mem_block = NULL;
 
+	/* Mark the tx sample completion */
+	stream->sample_tx_block_dma_sent++;
+
 	/* Stop transmission if there was an error */
 	if (stream->state == I2S_STATE_ERROR) {
 		LOG_ERR("TX error detected");
 		goto tx_disable;
 	}
 
+	/*
+	 * Check if the tx stop command can be handled
+	 * if True, the tx stop command can be handled
+	 */
+	if ((stream->state == I2S_STATE_STOPPING) && (status == DMA_STATUS_COMPLETE)) {
+		/*
+		 * Check if all tx samples have been completely handled
+		 * as stated in zephyr i2s specification, in case of DRAIN command
+		 * send all data in the transmit queue and stop the transmission.
+		 */
+		if (stream->sample_tx_block_sent == stream->sample_tx_block_dma_sent) {
+			stream->queue_drop(stream);
+			stream->state = I2S_STATE_READY;
+			goto tx_disable;
+		} else {
+			if (stream->sample_tx_stop_drain == false) {
+				/*
+				 * In case of STOP command, just stop the transmission
+				 * at the current. The transmission can be resumed.
+				 */
+				stream->state = I2S_STATE_READY;
+				goto tx_disable;
+			}
+		}
+	}
+
 	/* Stop transmission if we were requested */
 	if (stream->last_block) {
 		stream->state = I2S_STATE_READY;
@@ -652,11 +700,6 @@ static uint32_t i2s_stm32_irq_udr_count;
 static void i2s_stm32_isr(const struct device *dev)
 {
 	const struct i2s_stm32_cfg *cfg = dev->config;
-	struct i2s_stm32_data *const dev_data = dev->data;
-	struct stream *stream = &dev_data->rx;
-
-	LOG_ERR("%s: err=%d", __func__, (int)LL_I2S_ReadReg(cfg->i2s, SR));
-	stream->state = I2S_STATE_ERROR;
 
 	/* OVR error must be explicitly cleared */
 	if (LL_I2S_IsActiveFlag_OVR(cfg->i2s)) {
@@ -677,8 +720,14 @@ static int i2s_stm32_initialize(const struct device *dev)
 {
 	const struct i2s_stm32_cfg *cfg = dev->config;
 	struct i2s_stm32_data *const dev_data = dev->data;
+	struct stream *stream = &dev_data->tx;
 	int ret, i;
 
+	/* Initialize the variables used to handle the TX samples */
+	stream->sample_tx_block_sent = 0;
+	stream->sample_tx_block_dma_sent = 0;
+	stream->sample_tx_stop_drain = false;
+
 	/* Enable I2S clock propagation */
 	ret = i2s_stm32_enable_clock(dev);
 	if (ret < 0) {

drivers/i2s/i2s_ll_stm32.h

@@ -41,6 +41,9 @@ struct stream {
 	bool src_addr_increment;
 	bool dst_addr_increment;
 	uint8_t fifo_threshold;
+	uint8_t sample_tx_block_sent;
+	uint8_t sample_tx_block_dma_sent;
+	bool sample_tx_stop_drain;
 
 	struct i2s_config cfg;
 	struct ring_buf mem_block_queue;