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Groups > linux.kernel > #1406400 > unrolled thread

[PATCH 2/7] iio: adc: ad7791: claim direct mode when writing frequency

Started byAlison Schofield <amsfield22@gmail.com>
First post2016-05-24 21:20 +0200
Last post2016-05-29 19:10 +0200
Articles 4 — 3 participants

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  [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing  frequency Alison Schofield <amsfield22@gmail.com> - 2016-05-24 21:20 +0200
    Re: [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing frequency Daniel Baluta <daniel.baluta@gmail.com> - 2016-05-25 12:40 +0200
      Re: [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing  frequency Jonathan Cameron <jic23@kernel.org> - 2016-05-29 19:10 +0200
        Re: [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing  frequency Jonathan Cameron <jic23@kernel.org> - 2016-05-29 19:10 +0200

#1406400 — [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing frequency

FromAlison Schofield <amsfield22@gmail.com>
Date2016-05-24 21:20 +0200
Subject[PATCH 2/7] iio: adc: ad7791: claim direct mode when writing frequency
Message-ID<rCq1X-7jq-1@gated-at.bofh.it>
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.

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
---
 drivers/iio/adc/ad7791.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
index cf172d58..f7edacc 100644
--- a/drivers/iio/adc/ad7791.c
+++ b/drivers/iio/adc/ad7791.c
@@ -272,24 +272,17 @@ 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);
+			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);
-			mutex_unlock(&indio_dev->mlock);
+			iio_device_release_direct_mode(indio_dev);
 			ret = 0;
 			break;
 		}
-- 
2.1.4

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#1406824 — Re: [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing frequency

FromDaniel Baluta <daniel.baluta@gmail.com>
Date2016-05-25 12:40 +0200
SubjectRe: [PATCH 2/7] iio: adc: ad7791: claim direct mode when writing frequency
Message-ID<rCEoi-8jG-17@gated-at.bofh.it>
In reply to#1406400
On Tue, May 24, 2016 at 10:16 PM, Alison Schofield <amsfield22@gmail.com> 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.
>
> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
> Cc: Daniel Baluta <daniel.baluta@gmail.com>

Looks good to me. We could use an Acked-by from Lars here.

Acked-by: Daniel Baluta <daniel.baluta@gmail.com>

> ---
>  drivers/iio/adc/ad7791.c | 15 ++++-----------
>  1 file changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
> index cf172d58..f7edacc 100644
> --- a/drivers/iio/adc/ad7791.c
> +++ b/drivers/iio/adc/ad7791.c
> @@ -272,24 +272,17 @@ 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);
> +                       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);
> -                       mutex_unlock(&indio_dev->mlock);
> +                       iio_device_release_direct_mode(indio_dev);
>                         ret = 0;
>                         break;
>                 }
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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#1408614

FromJonathan Cameron <jic23@kernel.org>
Date2016-05-29 19:10 +0200
Message-ID<rEcnU-Fq-3@gated-at.bofh.it>
In reply to#1406824
On 25/05/16 11:34, Daniel Baluta wrote:
> On Tue, May 24, 2016 at 10:16 PM, Alison Schofield <amsfield22@gmail.com> 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.
>>
>> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
>> Cc: Daniel Baluta <daniel.baluta@gmail.com>
> 
> Looks good to me. We could use an Acked-by from Lars here.
> 
> Acked-by: Daniel Baluta <daniel.baluta@gmail.com>
This one is a little more interesting.  I wonder if we wouldn't be better
off taking the lock for the whole function rather than dropping it for
short periods.

Can apply such a change at a later date however.

Applied to the togreg branch of iio.git - initially pushed out as testing
for the autobuilders to play with it.

Thanks,

Jonathan

> 
>> ---
>>  drivers/iio/adc/ad7791.c | 15 ++++-----------
>>  1 file changed, 4 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
>> index cf172d58..f7edacc 100644
>> --- a/drivers/iio/adc/ad7791.c
>> +++ b/drivers/iio/adc/ad7791.c
>> @@ -272,24 +272,17 @@ 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);
>> +                       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);
>> -                       mutex_unlock(&indio_dev->mlock);
>> +                       iio_device_release_direct_mode(indio_dev);
>>                         ret = 0;
>>                         break;
>>                 }
>> --
>> 2.1.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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#1408617

FromJonathan Cameron <jic23@kernel.org>
Date2016-05-29 19:10 +0200
Message-ID<rEcnU-Fq-13@gated-at.bofh.it>
In reply to#1408614
On 29/05/16 18:06, Jonathan Cameron wrote:
> On 25/05/16 11:34, Daniel Baluta wrote:
>> On Tue, May 24, 2016 at 10:16 PM, Alison Schofield <amsfield22@gmail.com> 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.
>>>
>>> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
>>> Cc: Daniel Baluta <daniel.baluta@gmail.com>
>>
>> Looks good to me. We could use an Acked-by from Lars here.
>>
>> Acked-by: Daniel Baluta <daniel.baluta@gmail.com>
> This one is a little more interesting.  I wonder if we wouldn't be better
> off taking the lock for the whole function rather than dropping it for
> short periods.
> 
> Can apply such a change at a later date however.
> 
> Applied to the togreg branch of iio.git - initially pushed out as testing
> for the autobuilders to play with it.
Actually haven't seen Daniel suggesting an Ack from Lars might be good for this
one I've backed it out for now.

Lars?
> 
> Thanks,
> 
> Jonathan
> 
>>
>>> ---
>>>  drivers/iio/adc/ad7791.c | 15 ++++-----------
>>>  1 file changed, 4 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
>>> index cf172d58..f7edacc 100644
>>> --- a/drivers/iio/adc/ad7791.c
>>> +++ b/drivers/iio/adc/ad7791.c
>>> @@ -272,24 +272,17 @@ 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);
>>> +                       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);
>>> -                       mutex_unlock(&indio_dev->mlock);
>>> +                       iio_device_release_direct_mode(indio_dev);
>>>                         ret = 0;
>>>                         break;
>>>                 }
>>> --
>>> 2.1.4
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

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