From patchwork Wed Aug 5 07:02:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alain Volmat X-Patchwork-Id: 11701505 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EEA9C14DD for ; Wed, 5 Aug 2020 07:14:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9A912245C for ; Wed, 5 Aug 2020 07:14:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="mkeC+VtO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725920AbgHEHOT (ORCPT ); Wed, 5 Aug 2020 03:14:19 -0400 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:28436 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725809AbgHEHOT (ORCPT ); Wed, 5 Aug 2020 03:14:19 -0400 X-Greylist: delayed 591 seconds by postgrey-1.27 at vger.kernel.org; Wed, 05 Aug 2020 03:14:17 EDT Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 07573JwB012777; Wed, 5 Aug 2020 09:04:21 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=STMicroelectronics; bh=jqECQj44WsYLYEzqi6QoOeyI+LAhjmK9fRhP1wA1ILU=; b=mkeC+VtORiROhMUOKeGVfpExcYaqMo+6KObfxARlK6zLnEH/F2XyUY5KLi/iVT3DPjL1 y2nKk80f4L1yeqEaJsb9H7Je7HKN5BsmO8D2/sMJ1WX069vQWoiRjUnttvW4HwR5JR1B OfhYLAZv5f9AUTcOmj2QIyoNeElPqEj6m0cU7gQR1CAYzqNDnaKGHqBXDHxW6yiAysSu 3JndZlylCmuJxXrlGFWv6UTRfjhNK9NCa0mth2PWFby6tNcwYbthY9Ah/NQVWNq+UrhG 9+3CtxH2AogLMZkQ3DisM8rdGxsy5CyVdf7RHQko1E8ieEM617UBTxIRBIl2w7AexTwB Pw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 32n6theqj6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 05 Aug 2020 09:04:20 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 91046100038; Wed, 5 Aug 2020 09:04:20 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag3node2.st.com [10.75.127.8]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 85ACF2A4D8E; Wed, 5 Aug 2020 09:04:20 +0200 (CEST) Received: from localhost (10.75.127.51) by SFHDAG3NODE2.st.com (10.75.127.8) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 5 Aug 2020 09:04:20 +0200 From: Alain Volmat To: , CC: , , , , , , , Subject: [PATCH 17/18] spi: stm32: properly handle 0 byte transfer Date: Wed, 5 Aug 2020 09:02:12 +0200 Message-ID: <1596610933-32599-18-git-send-email-alain.volmat@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1596610933-32599-1-git-send-email-alain.volmat@st.com> References: <1596610933-32599-1-git-send-email-alain.volmat@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.51] X-ClientProxiedBy: SFHDAG3NODE2.st.com (10.75.127.8) To SFHDAG3NODE2.st.com (10.75.127.8) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-05_04:2020-08-03,2020-08-05 signatures=0 Sender: linux-spi-owner@vger.kernel.org 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. Signed-off-by: Alain Volmat --- drivers/spi/spi-stm32.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 177f82700de0..b909afd9e99b 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -1658,6 +1658,12 @@ static int stm32_spi_transfer_one(struct spi_master *master, unsigned long timeout; int ret; + /* Don't do anything on 0 bytes transfers */ + if (transfer->len == 0) { + spi->xfer_status = 0; + goto finalize; + } + spi->tx_buf = transfer->tx_buf; spi->rx_buf = transfer->rx_buf; spi->tx_len = spi->tx_buf ? transfer->len : 0; @@ -1702,6 +1708,7 @@ static int stm32_spi_transfer_one(struct spi_master *master, spi->cfg->disable(spi); +finalize: spi_finalize_current_transfer(master); return spi->xfer_status;