From patchwork Fri Feb 5 18:59:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alain Volmat X-Patchwork-Id: 377370 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 038A9C433DB for ; Fri, 5 Feb 2021 19:03:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A38F064E33 for ; Fri, 5 Feb 2021 19:02:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233689AbhBERUZ (ORCPT ); Fri, 5 Feb 2021 12:20:25 -0500 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:36876 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233725AbhBERS3 (ORCPT ); Fri, 5 Feb 2021 12:18:29 -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 115Ior36012827; Fri, 5 Feb 2021 19:59:46 +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=LjFrx5maoRvFpfTyBMerZ3asifVa9A9Yul9IroNU2aQ=; b=HJs9LqBdv9dd3pTqKh6Vmp/F+GKuIPKWR1CXU2NmDEFqMnWU72GEbtSv2CJk2j/b+1Wv SHRUUO+bF/9TkyEmrqCGFm2QNkn0KvCnkjs6LjqlaLiYQj6pgJTCu6EJ0ToUjd9orAkS CQPxbPjBY+GDJ76NA3L/ommC27aU4odGz9SBiA3ZTK1J8ZhSy1ELD7nTnN0OUmEQlXMb feu0JFrzexrZEdNkRbDGSM0zrKuNE3S459n1fXafVahEs6chCiXDYUB60WLjlMxLwqcM iE/oILeTXfNo1HxMUAgrNzrk17mxyjpHaMPenpU8VYP+zf+Pcz0QTonsBd8E7eRKPrwb AQ== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 36ey7hj46s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); 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: , CC: , , , , , , , 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 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 --- 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;