From patchwork Wed Sep 15 15:51:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 12496437 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=-16.7 required=3.0 tests=BAYES_00, 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 1F11AC433F5 for ; Wed, 15 Sep 2021 15:52:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0880D606A5 for ; Wed, 15 Sep 2021 15:52:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238758AbhIOPxT (ORCPT ); Wed, 15 Sep 2021 11:53:19 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:53463 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238257AbhIOPxF (ORCPT ); Wed, 15 Sep 2021 11:53:05 -0400 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 78650200010; Wed, 15 Sep 2021 15:51:25 +0000 (UTC) From: Miquel Raynal To: Jonathan Cameron , Lars-Peter Clausen , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Thomas Petazzoni , Nuno Sa , Miquel Raynal Subject: [PATCH v3 10/14] iio: adc: max1027: Prevent single channel accesses during buffer reads Date: Wed, 15 Sep 2021 17:51:13 +0200 Message-Id: <20210915155117.475962-11-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210915155117.475962-1-miquel.raynal@bootlin.com> References: <20210915155117.475962-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org When hardware buffers are enabled (the cnvst pin being the trigger), one should not mess with the device state by requesting a single channel read. There is already a iio_buffer_enabled() check in *_read_single_value() to merely prevent this situation but the check is inconsistent since buffers can be enabled after the if clause anyway. Instead, use the core mutex by calling iio_device_claim/release_direct_mode(). Signed-off-by: Miquel Raynal --- drivers/iio/adc/max1027.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c index 254df6a28cd8..c7663e5dd38a 100644 --- a/drivers/iio/adc/max1027.c +++ b/drivers/iio/adc/max1027.c @@ -310,10 +310,9 @@ static int max1027_read_single_value(struct iio_dev *indio_dev, int ret; struct max1027_state *st = iio_priv(indio_dev); - if (iio_buffer_enabled(indio_dev)) { - dev_warn(&indio_dev->dev, "trigger mode already enabled"); - return -EBUSY; - } + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; /* Configure conversion register with the requested chan */ st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) | @@ -324,6 +323,7 @@ static int max1027_read_single_value(struct iio_dev *indio_dev, if (ret < 0) { dev_err(&indio_dev->dev, "Failed to configure conversion register\n"); + iio_device_release_direct_mode(indio_dev); return ret; } @@ -336,6 +336,9 @@ static int max1027_read_single_value(struct iio_dev *indio_dev, /* Read result */ ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2); + + iio_device_release_direct_mode(indio_dev); + if (ret < 0) return ret;