diff mbox series

[17/18] spi: stm32: properly handle 0 byte transfer

Message ID 1596610933-32599-18-git-send-email-alain.volmat@st.com (mailing list archive)
State New, archived
Headers show
Series spi: stm32: various driver enhancements | expand

Commit Message

Alain Volmat Aug. 5, 2020, 7:02 a.m. UTC 
On 0 byte transfer request, return straight from the
xfer function after finalizing the transfer.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
 drivers/spi/spi-stm32.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff mbox series

Patch

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 177f82700de0..b909afd9e99b 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1658,6 +1658,12 @@  static int stm32_spi_transfer_one(struct spi_master *master,
 	unsigned long timeout;
 	int ret;
 
+	/* Don't do anything on 0 bytes transfers */
+	if (transfer->len == 0) {
+		spi->xfer_status = 0;
+		goto finalize;
+	}
+
 	spi->tx_buf = transfer->tx_buf;
 	spi->rx_buf = transfer->rx_buf;
 	spi->tx_len = spi->tx_buf ? transfer->len : 0;
@@ -1702,6 +1708,7 @@  static int stm32_spi_transfer_one(struct spi_master *master,
 
 	spi->cfg->disable(spi);
 
+finalize:
 	spi_finalize_current_transfer(master);
 
 	return spi->xfer_status;