| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 143/247] spi: stm32: properly handle 0 byte transfer | Date | Mon, 1 Mar 2021 17:12:43 +0100 |
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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.st.com 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 8eb2644506dd3..8d692f16d90ac 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -992,6 +992,10 @@ 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; -- 2.27.0
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