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Thu, 6 Mar 2025 16:02:09 -0500 Received: from ASHBCASHYB4.ad.analog.com (10.64.17.132) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.14; Thu, 6 Mar 2025 16:02:08 -0500 Received: from ASHBMBX8.ad.analog.com (10.64.17.5) by ASHBCASHYB4.ad.analog.com (10.64.17.132) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.14; Thu, 6 Mar 2025 16:02:08 -0500 Received: from zeus.spd.analog.com (10.66.68.11) by ashbmbx8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server id 15.2.986.14 via Frontend Transport; Thu, 6 Mar 2025 16:02:08 -0500 Received: from JSANTO12-L01.ad.analog.com ([10.65.60.206]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 526L1qVI011510; Thu, 6 Mar 2025 16:01:54 -0500 From: Jonathan Santos To: , , , CC: Jonathan Santos , , , , , , , , , , , , , , Subject: [PATCH v4 07/17] iio: adc: ad7768-1: remove unnecessary locking Date: Thu, 6 Mar 2025 18:01:51 -0300 Message-ID: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-GUID: 2XHgFoqEQ0PJ5UHhy0kVqwuQ-NmtFO90 X-Proofpoint-ORIG-GUID: 2XHgFoqEQ0PJ5UHhy0kVqwuQ-NmtFO90 X-Authority-Analysis: v=2.4 cv=E4w3pbdl c=1 sm=1 tr=0 ts=67ca0d52 cx=c_pps a=PpDZqlmH/M8setHirZLBMw==:117 a=PpDZqlmH/M8setHirZLBMw==:17 a=Vs1iUdzkB0EA:10 a=IpJZQVW2AAAA:8 a=gAnH3GRIAAAA:8 a=YKUZDo64jDh34TQBkAoA:9 a=IawgGOuG5U0WyFbmm1f5:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-06_07,2025-03-06_04,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 suspectscore=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 lowpriorityscore=0 malwarescore=0 impostorscore=0 phishscore=0 clxscore=1015 mlxscore=0 spamscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2502100000 definitions=main-2503060160 The current locking is only preventing a triggered buffer Transfer and a debugfs register access from happening at the same time. If a register access happens during a buffered read, the action is doomed to fail anyway, since we need to write a magic value to exit continuous read mode. Remove locking from the trigger handler and use iio_device_claim_direct_mode() instead in the register access function. Reviewed-by: David Lechner Signed-off-by: Jonathan Santos --- v4 Changes: * None. v3 Changes: * Also removed the mutex_init and lock variable. v2 Changes: * New patch in v2. It replaces the guard(mutex) patch. --- drivers/iio/adc/ad7768-1.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c index 2e2d50ccb744..f5509a0a36ab 100644 --- a/drivers/iio/adc/ad7768-1.c +++ b/drivers/iio/adc/ad7768-1.c @@ -154,7 +154,6 @@ static const struct iio_chan_spec ad7768_channels[] = { struct ad7768_state { struct spi_device *spi; struct regulator *vref; - struct mutex lock; struct clk *mclk; unsigned int mclk_freq; unsigned int samp_freq; @@ -256,18 +255,21 @@ static int ad7768_reg_access(struct iio_dev *indio_dev, struct ad7768_state *st = iio_priv(indio_dev); int ret; - mutex_lock(&st->lock); + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + if (readval) { ret = ad7768_spi_reg_read(st, reg, 1); if (ret < 0) - goto err_unlock; + goto err_release; *readval = ret; ret = 0; } else { ret = ad7768_spi_reg_write(st, reg, writeval); } -err_unlock: - mutex_unlock(&st->lock); +err_release: + iio_device_release_direct_mode(indio_dev); return ret; } @@ -471,18 +473,15 @@ static irqreturn_t ad7768_trigger_handler(int irq, void *p) struct ad7768_state *st = iio_priv(indio_dev); int ret; - mutex_lock(&st->lock); - ret = spi_read(st->spi, &st->data.scan.chan, 3); if (ret < 0) - goto err_unlock; + goto out; iio_push_to_buffers_with_timestamp(indio_dev, &st->data.scan, iio_get_time_ns(indio_dev)); -err_unlock: +out: iio_trigger_notify_done(indio_dev->trig); - mutex_unlock(&st->lock); return IRQ_HANDLED; } @@ -611,8 +610,6 @@ static int ad7768_probe(struct spi_device *spi) st->mclk_freq = clk_get_rate(st->mclk); - mutex_init(&st->lock); - indio_dev->channels = ad7768_channels; indio_dev->num_channels = ARRAY_SIZE(ad7768_channels); indio_dev->name = spi_get_device_id(spi)->name;