From: Alain Volmat Date: Fri, 5 Feb 2021 18:59:25 +0000 (+0100) Subject: spi: stm32: properly handle 0 byte transfer X-Git-Tag: v5.12-rc1~116^2^2~12 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2269f5a8b1a7;p=thirdparty%2Fkernel%2Flinux.git spi: stm32: properly handle 0 byte transfer 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 Link: https://lore.kernel.org/r/1612551572-495-2-git-send-email-alain.volmat@foss.st.com Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index db3e305d9ec47..6cdecd1c5ec79 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -1657,6 +1657,10 @@ 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;