drivers: spi: spi_mcux_lpspi: enable CONFIG_SPI_ASYNC mode with DMA

add DMA async support.

Signed-off-by: Derek Snell <[email protected]>

drivers/spi/spi_mcux_lpspi.c

@@ -322,26 +322,64 @@ static void spi_mcux_dma_callback(const struct device *dev, void *arg,
 		}
 	}
 #if CONFIG_SPI_ASYNC
+	int ret;
+
 	if (data->ctx.asynchronous &&
 	((data->status_flags & SPI_MCUX_LPSPI_DMA_DONE_FLAG)  ==
 	SPI_MCUX_LPSPI_DMA_DONE_FLAG)) {
+		/* dma_size of completed transfers were the same for TX and RX */
+		size_t dma_size = data->ctx.tx_len;
+
+		spi_context_update_tx(&data->ctx, 1, dma_size);
+		spi_context_update_rx(&data->ctx, 1, dma_size);
+
+		if (data->ctx.tx_len == 0 && data->ctx.rx_len == 0) {
+			spi_context_complete(&data->ctx, spi_dev, 0);
+			return;
+		}
+
+		/* Restart DMA for next buffer */
 		/* Load dma blocks of equal length */
-		size_t dma_size = MIN(data->ctx.tx_len, data->ctx.rx_len);
+		dma_size = MIN(data->ctx.tx_len, data->ctx.rx_len);
 
 		if (dma_size == 0) {
 			dma_size = MAX(data->ctx.tx_len, data->ctx.rx_len);
 		}
 
-		spi_context_update_tx(&data->ctx, 1, dma_size);
-		spi_context_update_rx(&data->ctx, 1, dma_size);
+		/* Clear status flags */
+		data->status_flags = 0U;
 
-		if (data->ctx.tx_len == 0 && data->ctx.rx_len == 0) {
-			spi_context_complete(&data->ctx, spi_dev, 0);
+		/* Restart the RX DMA */
+		ret = dma_reload(dev,
+				 data->dma_rx.channel,
+				 data->dma_rx.dma_blk_cfg.source_address,
+				 (uint32_t) data->ctx.rx_buf,
+				 dma_size);
+		if (ret != 0) {
+			LOG_ERR("RX dma_reload() failed with error %x.", ret);
+			data->status_flags |= SPI_MCUX_LPSPI_DMA_ERROR_FLAG;
+		}
+
+		/* Restart the TX DMA */
+		ret = dma_reload(dev,
+				 data->dma_tx.channel,
+				 (uint32_t) data->ctx.tx_buf,
+				 data->dma_tx.dma_blk_cfg.dest_address,
+				 dma_size);
+		if (ret != 0) {
+			LOG_ERR("TX dma_reload() failed with error %x.", ret);
+			data->status_flags |= SPI_MCUX_LPSPI_DMA_ERROR_FLAG;
 		}
+
 		return;
 	}
-#endif
+
+	if (!data->ctx.asynchronous) {
+		spi_context_complete(&data->ctx, spi_dev, 0);
+	}
+#else
 	spi_context_complete(&data->ctx, spi_dev, 0);
+#endif /* CONFIG_SPI_ASYNC */
 }
 
 static int spi_mcux_dma_tx_load(const struct device *dev, const uint8_t *buf, size_t len)