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: dcbe0d84df ("spi: add driver for STM32 SPI controller")
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-2-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Alain Volmat 2021-02-05 19:59:25 +01:00 committed by Greg Kroah-Hartman
parent 3cb8510625
commit 046a815898
1 changed files with 4 additions and 0 deletions

View File

@ -1668,6 +1668,10 @@ 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;