From: Claudiu Beznea <claudiu.beznea@microchip.com>
To: <eugen.hristev@microchip.com>, <jic23@kernel.org>,
<lars@metafoo.de>, <nicolas.ferre@microchip.com>,
<alexandre.belloni@bootlin.com>, <claudiu.beznea@microchip.com>,
<robh+dt@kernel.org>, <krzk+dt@kernel.org>
Cc: <linux-iio@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>
Subject: [PATCH v2 03/19] iio: adc: at91-sama5d2_adc: lock around oversampling and sample freq
Date: Tue, 28 Jun 2022 18:16:15 +0300 [thread overview]
Message-ID: <20220628151631.3116454-4-claudiu.beznea@microchip.com> (raw)
In-Reply-To: <20220628151631.3116454-1-claudiu.beznea@microchip.com>
.read_raw()/.write_raw() could be called asynchronously from user space
or other in kernel drivers. Without locking on st->lock these could be
called asynchronously while there is a conversion in progress. Read will
be harmless but changing registers while conversion is in progress may
lead to inconsistent results. Thus, to avoid this lock st->lock.
Fixes: 27e177190891 ("iio:adc:at91_adc8xx: introduce new atmel adc driver")
Fixes: 6794e23fa3fe ("iio: adc: at91-sama5d2_adc: add support for oversampling resolution")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
drivers/iio/adc/at91-sama5d2_adc.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index c3301c749164..40a95d2fd5c8 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -1542,10 +1542,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
ret = at91_adc_read_position(st, chan->channel,
&tmp_val);
*val = tmp_val;
- mutex_unlock(&st->lock);
- iio_device_release_direct_mode(indio_dev);
if (ret > 0)
ret = at91_adc_adjust_val_osr(st, val);
+ mutex_unlock(&st->lock);
+ iio_device_release_direct_mode(indio_dev);
return ret;
}
@@ -1558,10 +1558,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
ret = at91_adc_read_pressure(st, chan->channel,
&tmp_val);
*val = tmp_val;
- mutex_unlock(&st->lock);
- iio_device_release_direct_mode(indio_dev);
if (ret > 0)
ret = at91_adc_adjust_val_osr(st, val);
+ mutex_unlock(&st->lock);
+ iio_device_release_direct_mode(indio_dev);
return ret;
}
@@ -1650,16 +1650,20 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
/* if no change, optimize out */
if (val == st->oversampling_ratio)
return 0;
+ mutex_lock(&st->lock);
st->oversampling_ratio = val;
/* update ratio */
at91_adc_config_emr(st);
+ mutex_unlock(&st->lock);
return 0;
case IIO_CHAN_INFO_SAMP_FREQ:
if (val < st->soc_info.min_sample_rate ||
val > st->soc_info.max_sample_rate)
return -EINVAL;
+ mutex_lock(&st->lock);
at91_adc_setup_samp_freq(indio_dev, val);
+ mutex_unlock(&st->lock);
return 0;
default:
return -EINVAL;
--
2.34.1
next prev parent reply other threads:[~2022-06-28 15:14 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 15:16 [PATCH v2 00/19] iio: adc: at91-sama5d2_adc: add support for temperature sensor Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 01/19] iio: adc: at91-sama5d2_adc: fix AT91_SAMA5D2_MR_TRACKTIM_MAX Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 02/19] iio: adc: at91-sama5d2_adc: check return status for pressure and touch Claudiu Beznea
2022-07-16 16:25 ` Jonathan Cameron
2022-07-16 16:26 ` Jonathan Cameron
2022-06-28 15:16 ` Claudiu Beznea [this message]
2022-06-28 15:16 ` [PATCH v2 04/19] iio: adc: at91-sama5d2_adc: disable/prepare buffer on suspend/resume Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 05/19] iio: adc: at91-sama5d2_adc: exit from write_raw() when buffers are enabled Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 06/19] iio: adc: at91-sama5d2_adc: handle different EMR.OSR for different hw versions Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 07/19] iio: adc: at91-sama5d2_adc: move the check of oversampling in its function Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 08/19] iio: adc: at91-sama5d2_adc: drop AT91_OSR_XSAMPLES defines Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 09/19] iio: adc: at91-sama5d2_adc: add .read_avail() chan_info ops Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 10/19] iio: adc: at91-sama5d2_adc: adjust osr based on specific platform data Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 11/19] iio: adc: at91-sama5d2_adc: add 64 and 256 oversampling ratio Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 12/19] iio: adc: at91-sama5d2_adc: move oversampling storage in its function Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 13/19] iio: adc: at91-sama5d2_adc: update trackx on emr Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 14/19] iio: adc: at91-sama5d2_adc: add startup and tracktim as parameter for at91_adc_setup_samp_freq() Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 15/19] iio: adc: at91-sama5d2_adc: lock around at91_adc_read_info_raw() Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 16/19] dt-bindings: iio: adc: at91-sama5d2_adc: add id for temperature channel Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 17/19] iio: adc: at91-sama5d2_adc: add support for temperature sensor Claudiu Beznea
2022-07-16 16:35 ` Jonathan Cameron
2022-06-28 15:16 ` [PATCH v2 18/19] iio: adc: at91-sama5d2_adc: add empty line after functions Claudiu Beznea
2022-06-28 15:16 ` [PATCH v2 19/19] iio: adc: at91-sama5d2_adc: add runtime pm support Claudiu Beznea
2022-07-31 20:11 ` Jonathan Cameron
2022-08-01 9:44 ` Claudiu.Beznea
2022-07-16 16:42 ` [PATCH v2 00/19] iio: adc: at91-sama5d2_adc: add support for temperature sensor Jonathan Cameron
2022-07-31 20:13 ` Jonathan Cameron
2022-08-01 9:46 ` Claudiu.Beznea
2022-08-03 10:30 ` Claudiu.Beznea
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