From: Alain Volmat alain.volmat@foss.st.com
[ 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@foss.st.com Link: https://lore.kernel.org/r/1612551572-495-2-git-send-email-alain.volmat@foss.... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-stm32.c | 4 ++++ 1 file changed, 4 insertions(+)
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;