Commit 2f6f38cb authored Feb 05, 2021 by Alain Volmat Committed by Greg Kroah-Hartman Mar 04, 2021

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: dcbe0d84 ("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>

parent fd5560b4

drivers/spi/spi-stm32.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;