From patchwork Fri Feb 5 11:08:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alain Volmat X-Patchwork-Id: 12069983 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6495C433DB for ; Fri, 5 Feb 2021 11:17:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 601FF64DB2 for ; Fri, 5 Feb 2021 11:17:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231311AbhBELQ1 (ORCPT ); Fri, 5 Feb 2021 06:16:27 -0500 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:53238 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232025AbhBELKg (ORCPT ); Fri, 5 Feb 2021 06:10:36 -0500 Received: from pps.filterd (m0241204.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 115AojUa021324; Fri, 5 Feb 2021 12:09:44 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=selector1; bh=FCkDrTxbZDwU9CwRDiOr3Qlvt+6CQ9SFda6Q14KRmtE=; b=AjNDAZ4Tbg5BNwegVqNxY5TyOVFFJXz6OlNZGrZyQ60+NP4YBrjW6NlS9WsX4d6mjV8+ YWXYOZNfwJjULdfC9AAjWJVCNCh4fYC3RTu7rVeiDLSLpfj88Pnhm8HmEVTre8mTKXUq VKmgSNa1THWYkcuDYIPoFRYpHWCAS1BD6LtzYAqM4husMsyaU+rHuXR3rBd3cNtZDfM/ /SNeqFysEM4GmrUJB9O0ihjbm6nGq18cLji9ZVY/psL0Vylg+pfysYHBpSXca0wZFFPF IbpgIC4+xc3cBvmixVmSYDJlfetFWdJDFYc2ftNVJcw8l5pUR9F8ZI7CJTWDHAJocDha /A== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 36ey7hfu2j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 05 Feb 2021 12:09:44 +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 762C4100034; Fri, 5 Feb 2021 12:09:44 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 66AA4229F3C; Fri, 5 Feb 2021 12:09:44 +0100 (CET) Received: from localhost (10.75.127.50) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 5 Feb 2021 12:09:44 +0100 From: Alain Volmat To: , CC: , , , , , , , Subject: [PATCH 1/8] spi: stm32: properly handle 0 byte transfer Date: Fri, 5 Feb 2021 12:08:55 +0100 Message-ID: <1612523342-10466-2-git-send-email-alain.volmat@foss.st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1612523342-10466-1-git-send-email-alain.volmat@foss.st.com> References: <1612523342-10466-1-git-send-email-alain.volmat@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.50] X-ClientProxiedBy: SFHDAG2NODE1.st.com (10.75.127.4) 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_06:2021-02-05,2021-02-05 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.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 --- drivers/spi/spi-stm32.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index db3e305d9ec4..137213633e6d 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -1657,6 +1657,12 @@ 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) { + spi_finalize_current_transfer(master); + return 0; + } + spi->tx_buf = transfer->tx_buf; spi->rx_buf = transfer->rx_buf; spi->tx_len = spi->tx_buf ? transfer->len : 0;