From patchwork Mon Sep 28 13:13:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mircea Caprioru X-Patchwork-Id: 11803829 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 9CCAB139A for ; Mon, 28 Sep 2020 13:14:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EB092076D for ; Mon, 28 Sep 2020 13:14:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726667AbgI1NOV (ORCPT ); Mon, 28 Sep 2020 09:14:21 -0400 Received: from mx0a-00128a01.pphosted.com ([148.163.135.77]:24108 "EHLO mx0a-00128a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726681AbgI1NOU (ORCPT ); Mon, 28 Sep 2020 09:14:20 -0400 Received: from pps.filterd (m0167088.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08SD9Q3D011247; Mon, 28 Sep 2020 09:14:05 -0400 Received: from nwd2mta3.analog.com ([137.71.173.56]) by mx0a-00128a01.pphosted.com with ESMTP id 33syg5ycef-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Sep 2020 09:14:05 -0400 Received: from SCSQMBX10.ad.analog.com (scsqmbx10.ad.analog.com [10.77.17.5]) by nwd2mta3.analog.com (8.14.7/8.14.7) with ESMTP id 08SDE3Ge065282 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=FAIL); Mon, 28 Sep 2020 09:14:04 -0400 Received: from SCSQCASHYB6.ad.analog.com (10.77.17.132) by SCSQMBX10.ad.analog.com (10.77.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Mon, 28 Sep 2020 06:13:57 -0700 Received: from SCSQMBX11.ad.analog.com (10.77.17.10) by SCSQCASHYB6.ad.analog.com (10.77.17.132) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Mon, 28 Sep 2020 06:13:59 -0700 Received: from zeus.spd.analog.com (10.66.68.11) by SCSQMBX11.ad.analog.com (10.77.17.10) with Microsoft SMTP Server id 15.1.1779.2 via Frontend Transport; Mon, 28 Sep 2020 06:13:56 -0700 Received: from localhost.localdomain ([10.48.65.12]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 08SDDuB4030926; Mon, 28 Sep 2020 09:13:57 -0400 From: Mircea Caprioru To: CC: , , , , , , Sergiu Cuciurean , Mircea Caprioru Subject: [PATCH 1/5] iio: adc: spear_adc: Replace indio_dev->mlock with own device lock Date: Mon, 28 Sep 2020 16:13:29 +0300 Message-ID: <20200928131333.36646-1-mircea.caprioru@analog.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-ADIRoutedOnPrem: True X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-28_11:2020-09-28,2020-09-28 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 malwarescore=0 priorityscore=1501 impostorscore=0 suspectscore=0 lowpriorityscore=0 spamscore=0 bulkscore=0 mlxscore=0 clxscore=1011 mlxlogscore=607 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009280104 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 on the device's state structure. 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: Mircea Caprioru --- drivers/iio/adc/spear_adc.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/spear_adc.c b/drivers/iio/adc/spear_adc.c index 1bc986a7009d..d93e580b3dc5 100644 --- a/drivers/iio/adc/spear_adc.c +++ b/drivers/iio/adc/spear_adc.c @@ -75,6 +75,15 @@ struct spear_adc_state { struct adc_regs_spear6xx __iomem *adc_base_spear6xx; struct clk *clk; struct completion completion; + /* + * Lock to protect the device state during a potential concurrent + * read access from userspace. Reading a raw value requires a sequence + * of register writes, then a wait for a completion callback, + * and finally a register read, during which userspace could issue + * another read request. This lock protects a read access from + * ocurring before another one has finished. + */ + struct mutex lock; u32 current_clk; u32 sampling_freq; u32 avg_samples; @@ -146,7 +155,7 @@ static int spear_adc_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: - mutex_lock(&indio_dev->mlock); + mutex_lock(&st->lock); status = SPEAR_ADC_STATUS_CHANNEL_NUM(chan->channel) | SPEAR_ADC_STATUS_AVG_SAMPLE(st->avg_samples) | @@ -159,7 +168,7 @@ static int spear_adc_read_raw(struct iio_dev *indio_dev, wait_for_completion(&st->completion); /* set by ISR */ *val = st->value; - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&st->lock); return IIO_VAL_INT; @@ -187,7 +196,7 @@ static int spear_adc_write_raw(struct iio_dev *indio_dev, if (mask != IIO_CHAN_INFO_SAMP_FREQ) return -EINVAL; - mutex_lock(&indio_dev->mlock); + mutex_lock(&st->lock); if ((val < SPEAR_ADC_CLK_MIN) || (val > SPEAR_ADC_CLK_MAX) || @@ -199,7 +208,7 @@ static int spear_adc_write_raw(struct iio_dev *indio_dev, spear_adc_set_clk(st, val); out: - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&st->lock); return ret; } @@ -271,6 +280,9 @@ static int spear_adc_probe(struct platform_device *pdev) } st = iio_priv(indio_dev); + + mutex_init(&st->lock); + st->np = np; /*