From patchwork Fri Jan 5 14:34:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 10146643 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1A3F360244 for ; Fri, 5 Jan 2018 14:36:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0911C287B5 for ; Fri, 5 Jan 2018 14:36:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F1CBA287BA; Fri, 5 Jan 2018 14:36:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A24E9287B5 for ; Fri, 5 Jan 2018 14:36:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788AbeAEOgQ (ORCPT ); Fri, 5 Jan 2018 09:36:16 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:25679 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751609AbeAEOgQ (ORCPT ); Fri, 5 Jan 2018 09:36:16 -0500 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id w05EYX8d030085; Fri, 5 Jan 2018 15:35:30 +0100 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 2f9hfsnq4a-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Fri, 05 Jan 2018 15:35:30 +0100 Received: from zeta.dmz-eu.st.com (zeta.dmz-eu.st.com [164.129.230.9]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id BBAA431; Fri, 5 Jan 2018 14:35:28 +0000 (GMT) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by zeta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 97A9313DE; Fri, 5 Jan 2018 14:35:28 +0000 (GMT) Received: from localhost (10.75.127.48) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 5 Jan 2018 15:35:28 +0100 From: Fabrice Gasnier To: CC: , , , , , , , , Subject: [PATCH] iio: adc: stm32: fix scan of multiple channels with DMA Date: Fri, 5 Jan 2018 15:34:54 +0100 Message-ID: <1515162894-11637-1-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 X-Originating-IP: [10.75.127.48] X-ClientProxiedBy: SFHDAG1NODE2.st.com (10.75.127.2) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-01-05_07:, , signatures=0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP By default, watermark is set to '1'. Watermark is used to fine tune cyclic dma buffer period. In case watermark is left untouched (e.g. 1) and several channels are being scanned, buffer period is wrongly set (e.g. to 1 sample). As a consequence, data is never pushed to upper layer. Fix buffer period size, by taking scan channels number into account. Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support") Signed-off-by: Fabrice Gasnier --- drivers/iio/adc/stm32-adc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index c9d96f9..cecf1e5 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1315,6 +1315,7 @@ static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val) { struct stm32_adc *adc = iio_priv(indio_dev); unsigned int watermark = STM32_DMA_BUFFER_SIZE / 2; + unsigned int rx_buf_sz = STM32_DMA_BUFFER_SIZE; /* * dma cyclic transfers are used, buffer is split into two periods. @@ -1323,7 +1324,7 @@ static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val) * - one buffer (period) driver can push with iio_trigger_poll(). */ watermark = min(watermark, val * (unsigned)(sizeof(u16))); - adc->rx_buf_sz = watermark * 2; + adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv); return 0; }