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Tue, 4 Oct 2022 09:49:04 -0400 From: =?utf-8?q?Nuno_S=C3=A1?= To: , , , , CC: Heiko Stuebner , Martin Blumenstingl , Neil Armstrong , Shawn Guo , "Lars-Peter Clausen" , Jyoti Bhayana , Hans de Goede , Andriy Tryshnivskyy , Pengutronix Kernel Team , Miquel Raynal , Cixi Geng , Baolin Wang , "Ciprian Regus" , Fabio Estevam , =?utf-8?q?Nuno_S=C3=A1?= , Sascha Hauer , Alexandru Ardelean , "Florian Boor" , Michael Hennerich , Orson Zhai , "Chen-Yu Tsai" , Chunyan Zhang , "Vladimir Zapolskiy" , Andy Shevchenko , "Jerome Brunet" , Haibo Chen , Kevin Hilman , Jonathan Cameron Subject: [PATCH v2 10/16] iio: adc: vf610_adc: vf610_adc: do not use internal iio_dev lock Date: Tue, 4 Oct 2022 15:49:03 +0200 Message-ID: <20221004134909.1692021-11-nuno.sa@analog.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221004134909.1692021-1-nuno.sa@analog.com> References: <20221004134909.1692021-1-nuno.sa@analog.com> MIME-Version: 1.0 X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-GUID: k3wrSbYPLdlik_JMrtGFyhbH8mmV20dI X-Proofpoint-ORIG-GUID: k3wrSbYPLdlik_JMrtGFyhbH8mmV20dI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-10-04_06,2022-09-29_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 malwarescore=0 bulkscore=0 mlxscore=0 priorityscore=1501 spamscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 phishscore=0 suspectscore=0 mlxlogscore=684 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210040089 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221004_064929_340340_09BC75F6 X-CRM114-Status: GOOD ( 18.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In order to drop the internal lock usage we needed two different things: 1) The first place where 'mlock' was being used was a typical case where iio_device_claim_direct_mode() fits perfectly. 2) In the second case, it was being used to prevent concurrent accesses to the device and shared data but nothing was being enforced with regards to buffering (i.e, there was nothing preventing from changing the conversion mode while buffering). Hence, in this case, a new lock was introduced in the state structure. Note that the goal is not to introduce any functional change and that is the reason why a new lock was introduced to guarantee 2). While at it, properly include "mutex.h" for mutex related APIs. Signed-off-by: Nuno Sá Reviewed-by: Haibo Chen --- drivers/iio/adc/vf610_adc.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c index a6f9182d7766..ae31aafd2653 100644 --- a/drivers/iio/adc/vf610_adc.c +++ b/drivers/iio/adc/vf610_adc.c @@ -7,6 +7,7 @@ #include #include +#include #include #include #include @@ -156,6 +157,9 @@ struct vf610_adc { void __iomem *regs; struct clk *clk; + /* lock to protect against multiple access to the device */ + struct mutex lock; + u32 vref_uv; u32 value; struct regulator *vref; @@ -467,11 +471,11 @@ static int vf610_set_conversion_mode(struct iio_dev *indio_dev, { struct vf610_adc *info = iio_priv(indio_dev); - mutex_lock(&indio_dev->mlock); + mutex_lock(&info->lock); info->adc_feature.conv_mode = mode; vf610_adc_calculate_rates(info); vf610_adc_hw_init(info); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return 0; } @@ -629,12 +633,11 @@ static int vf610_read_sample(struct iio_dev *indio_dev, unsigned int hc_cfg; int ret; - mutex_lock(&indio_dev->mlock); - if (iio_buffer_enabled(indio_dev)) { - ret = -EBUSY; - goto out_unlock; - } + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + mutex_lock(&info->lock); reinit_completion(&info->completion); hc_cfg = VF610_ADC_ADCHC(chan->channel); hc_cfg |= VF610_ADC_AIEN; @@ -669,7 +672,8 @@ static int vf610_read_sample(struct iio_dev *indio_dev, } out_unlock: - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); + iio_device_release_direct_mode(indio_dev); return ret; } @@ -892,6 +896,8 @@ static int vf610_adc_probe(struct platform_device *pdev) goto error_iio_device_register; } + mutex_init(&info->lock); + ret = iio_device_register(indio_dev); if (ret) { dev_err(&pdev->dev, "Couldn't register the device.\n");