From patchwork Wed Sep 16 09:23:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Ardelean X-Patchwork-Id: 11779421 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 665036CA for ; Wed, 16 Sep 2020 09:24:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5568722208 for ; Wed, 16 Sep 2020 09:24:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726696AbgIPJYN (ORCPT ); Wed, 16 Sep 2020 05:24:13 -0400 Received: from mx0a-00128a01.pphosted.com ([148.163.135.77]:63740 "EHLO mx0a-00128a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726369AbgIPJYM (ORCPT ); Wed, 16 Sep 2020 05:24:12 -0400 Received: from pps.filterd (m0167089.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08G97XOM027922; Wed, 16 Sep 2020 05:23:59 -0400 Received: from nwd2mta4.analog.com ([137.71.173.58]) by mx0a-00128a01.pphosted.com with ESMTP id 33k5q51vsh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 16 Sep 2020 05:23:59 -0400 Received: from ASHBMBX8.ad.analog.com (ashbmbx8.ad.analog.com [10.64.17.5]) by nwd2mta4.analog.com (8.14.7/8.14.7) with ESMTP id 08G9NvSn049529 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=FAIL); Wed, 16 Sep 2020 05:23:57 -0400 Received: from ASHBCASHYB5.ad.analog.com (10.64.17.133) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Wed, 16 Sep 2020 05:24:05 -0400 Received: from ASHBMBX8.ad.analog.com (10.64.17.5) by ASHBCASHYB5.ad.analog.com (10.64.17.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Wed, 16 Sep 2020 05:24:05 -0400 Received: from zeus.spd.analog.com (10.66.68.11) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server id 15.1.1779.2 via Frontend Transport; Wed, 16 Sep 2020 05:24:05 -0400 Received: from localhost.localdomain ([10.48.65.12]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 08G9NnPn021992; Wed, 16 Sep 2020 05:23:50 -0400 From: Alexandru Ardelean To: , , , CC: , , , , , Sergiu Cuciurean , Alexandru Ardelean Subject: [PATCH v2] iio: stm32-dac: Replace indio_dev->mlock with own device lock Date: Wed, 16 Sep 2020 12:23:49 +0300 Message-ID: <20200916092349.75647-1-alexandru.ardelean@analog.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200826063850.47625-1-alexandru.ardelean@analog.com> References: <20200826063850.47625-1-alexandru.ardelean@analog.com> MIME-Version: 1.0 X-ADIRoutedOnPrem: True X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-16_02:2020-09-15,2020-09-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 clxscore=1011 impostorscore=0 mlxscore=0 malwarescore=0 phishscore=0 mlxlogscore=545 lowpriorityscore=0 suspectscore=0 priorityscore=1501 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009160068 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Sergiu Cuciurean As part of the general cleanup of indio_dev->mlock, this change replaces it with a local lock. The lock protects against potential races when reading the CR reg and then updating, so that the state of pm_runtime is consistent between the two operations. This is part of a bigger cleanup. Link: https://lore.kernel.org/linux-iio/CA+U=Dsoo6YABe5ODLp+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@mail.gmail.com/ Signed-off-by: Sergiu Cuciurean Signed-off-by: Alexandru Ardelean Reviewed-by: Fabrice Gasnier --- drivers/iio/dac/stm32-dac.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c index 092c796fa3d9..12dec68c16f7 100644 --- a/drivers/iio/dac/stm32-dac.c +++ b/drivers/iio/dac/stm32-dac.c @@ -26,9 +26,12 @@ /** * struct stm32_dac - private data of DAC driver * @common: reference to DAC common data + * @lock: lock to protect against potential races when reading + * and update CR, to keep it in sync with pm_runtime */ struct stm32_dac { struct stm32_dac_common *common; + struct mutex lock; }; static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel) @@ -58,10 +61,10 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch, int ret; /* already enabled / disabled ? */ - mutex_lock(&indio_dev->mlock); + mutex_lock(&dac->lock); ret = stm32_dac_is_enabled(indio_dev, ch); if (ret < 0 || enable == !!ret) { - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&dac->lock); return ret < 0 ? ret : 0; } @@ -69,13 +72,13 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch, ret = pm_runtime_get_sync(dev); if (ret < 0) { pm_runtime_put_noidle(dev); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&dac->lock); return ret; } } ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&dac->lock); if (ret < 0) { dev_err(&indio_dev->dev, "%s failed\n", en ? "Enable" : "Disable"); @@ -327,6 +330,8 @@ static int stm32_dac_probe(struct platform_device *pdev) indio_dev->info = &stm32_dac_iio_info; indio_dev->modes = INDIO_DIRECT_MODE; + mutex_init(&dac->lock); + ret = stm32_dac_chan_of_init(indio_dev); if (ret < 0) return ret;