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Fri, 05 Feb 2021 19:59:46 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id B54B6100034; Fri, 5 Feb 2021 19:59:45 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id A88612C38D3; Fri, 5 Feb 2021 19:59:45 +0100 (CET) Received: from localhost (10.75.127.46) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 5 Feb 2021 19:59:45 +0100 From: Alain Volmat To: , Subject: [PATCH v2 1/8] spi: stm32: properly handle 0 byte transfer Date: Fri, 5 Feb 2021 19:59:25 +0100 Message-ID: <1612551572-495-2-git-send-email-alain.volmat@foss.st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1612551572-495-1-git-send-email-alain.volmat@foss.st.com> References: <1612551572-495-1-git-send-email-alain.volmat@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG1NODE3.st.com (10.75.127.3) To SFHDAG2NODE3.st.com (10.75.127.6) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.737 definitions=2021-02-05_10:2021-02-05, 2021-02-05 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210205_135952_815128_21C82CEB X-CRM114-Status: GOOD ( 16.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, alexandre.torgue@foss.st.com, fabrice.gasnier@foss.st.com, mcoquelin.stm32@gmail.com, alain.volmat@foss.st.com, linux-spi@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 --- v2: remove useless spi_finalize_current_transfer 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 db3e305d9ec4..6cdecd1c5ec7 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;