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* [PATCH v2 2/7] iio: adc: ad7791: claim direct mode when writing frequency
@ 2016-06-01  4:35 Alison Schofield
  2016-06-01 19:10 ` Lars-Peter Clausen
  0 siblings, 1 reply; 3+ messages in thread
From: Alison Schofield @ 2016-06-01  4:35 UTC (permalink / raw)
  To: jic23; +Cc: lars, Michael.Hennerich, knaack.h, pmeerw, linux-iio, linux-kernel

Driver was checking for direct mode and trying to lock it, but
left a gap where mode could change before the desired operation.
Use iio_device_claim_direct_mode() to guarantee device stays in
direct mode.

Refactor function to clarify look-up followed by lock sequence.

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
---
Changes in v2
Refactored function per reviewers comments
Updated changelog

 drivers/iio/adc/ad7791.c | 36 ++++++++++++++----------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
index cf172d58..1dfe641 100644
--- a/drivers/iio/adc/ad7791.c
+++ b/drivers/iio/adc/ad7791.c
@@ -272,30 +272,22 @@ static ssize_t ad7791_write_frequency(struct device *dev,
 	struct ad7791_state *st = iio_priv(indio_dev);
 	int i, ret;
 
-	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_enabled(indio_dev)) {
-		mutex_unlock(&indio_dev->mlock);
-		return -EBUSY;
-	}
-	mutex_unlock(&indio_dev->mlock);
-
-	ret = -EINVAL;
-
-	for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
-		if (sysfs_streq(ad7791_sample_freq_avail[i], buf)) {
-
-			mutex_lock(&indio_dev->mlock);
-			st->filter &= ~AD7791_FILTER_RATE_MASK;
-			st->filter |= i;
-			ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
-					 sizeof(st->filter), st->filter);
-			mutex_unlock(&indio_dev->mlock);
-			ret = 0;
+	for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++)
+		if (sysfs_streq(ad7791_sample_freq_avail[i], buf))
 			break;
-		}
-	}
+	if (i == ARRAY_SIZE(ad7791_sample_freq_avail))
+		return -EINVAL;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+	st->filter &= ~AD7791_FILTER_RATE_MASK;
+	st->filter |= i;
+	ad_sd_write_reg(&st->sd, AD7791_REG_FILTER, sizeof(st->filter),
+			st->filter);
+	iio_device_release_direct_mode(indio_dev);
 
-	return ret ? ret : len;
+	return len;
 }
 
 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
-- 
2.1.4

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v2 2/7] iio: adc: ad7791: claim direct mode when writing frequency
  2016-06-01  4:35 [PATCH v2 2/7] iio: adc: ad7791: claim direct mode when writing frequency Alison Schofield
@ 2016-06-01 19:10 ` Lars-Peter Clausen
  2016-06-03 12:13   ` Jonathan Cameron
  0 siblings, 1 reply; 3+ messages in thread
From: Lars-Peter Clausen @ 2016-06-01 19:10 UTC (permalink / raw)
  To: Alison Schofield, jic23
  Cc: Michael.Hennerich, knaack.h, pmeerw, linux-iio, linux-kernel

On 06/01/2016 06:35 AM, Alison Schofield wrote:
> Driver was checking for direct mode and trying to lock it, but
> left a gap where mode could change before the desired operation.
> Use iio_device_claim_direct_mode() to guarantee device stays in
> direct mode.
> 
> Refactor function to clarify look-up followed by lock sequence.
> 
> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
> Cc: Daniel Baluta <daniel.baluta@gmail.com>

Looks good, thanks.

Acked-by: Lars-Peter Clausen <lars@metafoo.de>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2 2/7] iio: adc: ad7791: claim direct mode when writing frequency
  2016-06-01 19:10 ` Lars-Peter Clausen
@ 2016-06-03 12:13   ` Jonathan Cameron
  0 siblings, 0 replies; 3+ messages in thread
From: Jonathan Cameron @ 2016-06-03 12:13 UTC (permalink / raw)
  To: Lars-Peter Clausen, Alison Schofield
  Cc: Michael.Hennerich, knaack.h, pmeerw, linux-iio, linux-kernel

On 01/06/16 20:10, Lars-Peter Clausen wrote:
> On 06/01/2016 06:35 AM, Alison Schofield wrote:
>> Driver was checking for direct mode and trying to lock it, but
>> left a gap where mode could change before the desired operation.
>> Use iio_device_claim_direct_mode() to guarantee device stays in
>> direct mode.
>>
>> Refactor function to clarify look-up followed by lock sequence.
>>
>> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
>> Cc: Daniel Baluta <daniel.baluta@gmail.com>
> 
> Looks good, thanks.
> 
> Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Applied - thanks.
> 
> --
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> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2016-06-03 12:13 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2016-06-01  4:35 [PATCH v2 2/7] iio: adc: ad7791: claim direct mode when writing frequency Alison Schofield
2016-06-01 19:10 ` Lars-Peter Clausen
2016-06-03 12:13   ` Jonathan Cameron

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