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[PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency

Started byAlison Schofield <amsfield22@gmail.com>
First post2016-05-24 21:20 +0200
Last post2016-05-29 20:40 +0200
Articles 3 — 3 participants

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  [PATCH 3/7] iio: adc: ad7793: claim direct mode when writing  frequency Alison Schofield <amsfield22@gmail.com> - 2016-05-24 21:20 +0200
    Re: [PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency Daniel Baluta <daniel.baluta@gmail.com> - 2016-05-25 12:40 +0200
      Re: [PATCH 3/7] iio: adc: ad7793: claim direct mode when writing  frequency Jonathan Cameron <jic23@kernel.org> - 2016-05-29 20:40 +0200

#1406401 — [PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency

FromAlison Schofield <amsfield22@gmail.com>
Date2016-05-24 21:20 +0200
Subject[PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency
Message-ID<rCq1X-7jq-21@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/ad7793.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
index 7b07bb6..3f41cd8 100644
--- a/drivers/iio/adc/ad7793.c
+++ b/drivers/iio/adc/ad7793.c
@@ -369,13 +369,6 @@ static ssize_t ad7793_write_frequency(struct device *dev,
 	long lval;
 	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 = kstrtol(buf, 10, &lval);
 	if (ret)
 		return ret;
@@ -387,12 +380,14 @@ static ssize_t ad7793_write_frequency(struct device *dev,
 
 	for (i = 0; i < 16; i++)
 		if (lval == st->chip_info->sample_freq_avail[i]) {
-			mutex_lock(&indio_dev->mlock);
+			ret = iio_device_claim_direct_mode(indio_dev);
+			if (ret)
+				return ret;
 			st->mode &= ~AD7793_MODE_RATE(-1);
 			st->mode |= AD7793_MODE_RATE(i);
 			ad_sd_write_reg(&st->sd, AD7793_REG_MODE,
 					 sizeof(st->mode), st->mode);
-			mutex_unlock(&indio_dev->mlock);
+			iio_device_release_direct_mode(indio_dev);
 			ret = 0;
 		}
 
-- 
2.1.4

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#1406823 — Re: [PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency

FromDaniel Baluta <daniel.baluta@gmail.com>
Date2016-05-25 12:40 +0200
SubjectRe: [PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency
Message-ID<rCEoi-8jG-13@gated-at.bofh.it>
In reply to#1406401
On Tue, May 24, 2016 at 10:17 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>

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

> ---
>  drivers/iio/adc/ad7793.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
> index 7b07bb6..3f41cd8 100644
> --- a/drivers/iio/adc/ad7793.c
> +++ b/drivers/iio/adc/ad7793.c
> @@ -369,13 +369,6 @@ static ssize_t ad7793_write_frequency(struct device *dev,
>         long lval;
>         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 = kstrtol(buf, 10, &lval);
>         if (ret)
>                 return ret;
> @@ -387,12 +380,14 @@ static ssize_t ad7793_write_frequency(struct device *dev,
>
>         for (i = 0; i < 16; i++)
>                 if (lval == st->chip_info->sample_freq_avail[i]) {
> -                       mutex_lock(&indio_dev->mlock);
> +                       ret = iio_device_claim_direct_mode(indio_dev);
> +                       if (ret)
> +                               return ret;
>                         st->mode &= ~AD7793_MODE_RATE(-1);
>                         st->mode |= AD7793_MODE_RATE(i);
>                         ad_sd_write_reg(&st->sd, AD7793_REG_MODE,
>                                          sizeof(st->mode), st->mode);
> -                       mutex_unlock(&indio_dev->mlock);
> +                       iio_device_release_direct_mode(indio_dev);
>                         ret = 0;
>                 }
>
> --

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#1408637

FromJonathan Cameron <jic23@kernel.org>
Date2016-05-29 20:40 +0200
Message-ID<rEdN0-1qk-21@gated-at.bofh.it>
In reply to#1406823
On 25/05/16 11:36, Daniel Baluta wrote:
> On Tue, May 24, 2016 at 10:17 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>
> 
> Acked-by: Daniel Baluta <daniel.baluta@gmail.com>
Again, this one is not quite so trivial so I'll wait for Lars to take a look
even though I'm happy with it.

Thanks,

Jonathan
> 
>> ---
>>  drivers/iio/adc/ad7793.c | 13 ++++---------
>>  1 file changed, 4 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
>> index 7b07bb6..3f41cd8 100644
>> --- a/drivers/iio/adc/ad7793.c
>> +++ b/drivers/iio/adc/ad7793.c
>> @@ -369,13 +369,6 @@ static ssize_t ad7793_write_frequency(struct device *dev,
>>         long lval;
>>         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 = kstrtol(buf, 10, &lval);
>>         if (ret)
>>                 return ret;
>> @@ -387,12 +380,14 @@ static ssize_t ad7793_write_frequency(struct device *dev,
>>
>>         for (i = 0; i < 16; i++)
>>                 if (lval == st->chip_info->sample_freq_avail[i]) {
>> -                       mutex_lock(&indio_dev->mlock);
>> +                       ret = iio_device_claim_direct_mode(indio_dev);
>> +                       if (ret)
>> +                               return ret;
>>                         st->mode &= ~AD7793_MODE_RATE(-1);
>>                         st->mode |= AD7793_MODE_RATE(i);
>>                         ad_sd_write_reg(&st->sd, AD7793_REG_MODE,
>>                                          sizeof(st->mode), st->mode);
>> -                       mutex_unlock(&indio_dev->mlock);
>> +                       iio_device_release_direct_mode(indio_dev);
>>                         ret = 0;
>>                 }
>>
>> --
> --
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