This is a note to let you know that I've just added the patch titled
spi: stm32: properly handle 0 byte transfer
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-stm32-properly-handle-0-byte-transfer.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ae5fafd7811bca57add7f6c407cd255e2d1f2ff9
Author: Alain Volmat <alain.volmat@xxxxxxxxxxx>
Date: Fri Feb 5 19:59:25 2021 +0100
spi: stm32: properly handle 0 byte transfer
[ Upstream commit 2269f5a8b1a7b38651d62676b98182828f29d11a ]
On 0 byte transfer request, return straight from the
xfer function after finalizing the transfer.
Fixes: dcbe0d84dfa5 ("spi: add driver for STM32 SPI controller")
Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/1612551572-495-2-git-send-email-alain.volmat@xxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 6017209c6d2f7..6eeb39669a866 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1677,6 +1677,10 @@ static int stm32_spi_transfer_one(struct spi_master *master,
struct stm32_spi *spi = spi_master_get_devdata(master);
int ret;
+ /* Don't do anything on 0 bytes transfers */
+ if (transfer->len == 0)
+ return 0;
+
spi->tx_buf = transfer->tx_buf;
spi->rx_buf = transfer->rx_buf;
spi->tx_len = spi->tx_buf ? transfer->len : 0;
