drivers: spi: Correct condition for continuing data transfer

When performing polling-based data transfer without enabling interrupts,
the current implementation stops transferring as soon as either the TX or
RX buffer becomes NULL. This causes the transfer to stop prematurely,
even if the other direction still has data to send or receive.

This commit fixes the condition so that data transfer continues
as long as one direction (TX or RX) still has data remaining.

Signed-off-by: Khoa Tran <[email protected]>

Author: khoatranyj

drivers/spi/spi_b_renesas_ra8.c

@@ -161,15 +161,7 @@ static int ra_spi_b_configure(const struct device *dev, const struct spi_config
 
 static bool ra_spi_b_transfer_ongoing(struct ra_spi_data *data)
 {
-#if defined(CONFIG_SPI_B_INTERRUPT)
 	return (spi_context_tx_on(&data->ctx) || spi_context_rx_on(&data->ctx));
-#else
-	if (spi_context_total_tx_len(&data->ctx) < spi_context_total_rx_len(&data->ctx)) {
-		return (spi_context_tx_on(&data->ctx) || spi_context_rx_on(&data->ctx));
-	} else {
-		return (spi_context_tx_on(&data->ctx) && spi_context_rx_on(&data->ctx));
-	}
-#endif
 }
 
 #ifndef CONFIG_SPI_B_INTERRUPT
@@ -241,26 +233,28 @@ static int ra_spi_b_transceive_master(struct ra_spi_data *data)
 
 	while (!p_spi_reg->SPSR_b.SPTEF) {
 	}
-
 	p_spi_reg->SPDR = tx;
 
 	/* Clear Transmit Empty flag */
 	p_spi_reg->SPSRC = R_SPI_B0_SPSRC_SPTEFC_Msk;
 	spi_context_update_tx(&data->ctx, data->dfs, 1);
 
-	/* Rx receive */
-	if (spi_context_rx_on(&data->ctx)) {
+	if (p_spi_reg->SPCR_b.TXMD == 0x0) {
 		while (!p_spi_reg->SPSR_b.SPRF) {
 		}
 		rx = p_spi_reg->SPDR;
 		/* Clear Receive Full flag */
 		p_spi_reg->SPSRC = R_SPI_B0_SPSRC_SPRFC_Msk;
-		if (data->dfs > 2) {
-			UNALIGNED_PUT(rx, (uint32_t *)data->ctx.rx_buf);
-		} else if (data->dfs > 1) {
-			UNALIGNED_PUT(rx, (uint16_t *)data->ctx.rx_buf);
-		} else {
-			UNALIGNED_PUT(rx, (uint8_t *)data->ctx.rx_buf);
+
+		/* Rx receive */
+		if (spi_context_rx_buf_on(&data->ctx)) {
+			if (data->dfs > 2) {
+				UNALIGNED_PUT(rx, (uint32_t *)data->ctx.rx_buf);
+			} else if (data->dfs > 1) {
+				UNALIGNED_PUT(rx, (uint16_t *)data->ctx.rx_buf);
+			} else {
+				UNALIGNED_PUT(rx, (uint8_t *)data->ctx.rx_buf);
+			}
 		}
 		spi_context_update_rx(&data->ctx, data->dfs, 1);
 	}
@@ -349,9 +343,6 @@ static int transceive(const struct device *dev, const struct spi_config *config,
 
 #else
 	p_spi_reg->SPCR_b.TXMD = 0x0; /* tx - rx*/
-	if (!spi_context_tx_on(&data->ctx)) {
-		p_spi_reg->SPCR_b.TXMD = 0x2; /* rx only */
-	}
 	if (!spi_context_rx_on(&data->ctx)) {
 		p_spi_reg->SPCR_b.TXMD = 0x1; /* tx only */
 	}