[PATCH] iio: core: Avoid double minus in sysfs output

[PATCH] iio: core: Avoid double minus in sysfs output

[Oleksandr Kravchenko]

From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>

This patch fixes the issue with double minus in output when
reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
both are negatives output string contains "--" before
digits. It is result of "-%d..." in sprintf() format.

Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
---
 drivers/iio/industrialio-core.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index d56d122..455c24b 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -383,14 +383,14 @@ static ssize_t iio_read_channel_info(struct device *dev,
 		scale_db = true;
 	case IIO_VAL_INT_PLUS_MICRO:
 		if (val2 < 0)
-			return sprintf(buf, "-%d.%06u%s\n", val, -val2,
-				scale_db ? " dB" : "");
+			return sprintf(buf, "-%d.%06u%s\n", (int)abs(val),
+				-val2, scale_db ? " dB" : "");
 		else
 			return sprintf(buf, "%d.%06u%s\n", val, val2,
 				scale_db ? " dB" : "");
 	case IIO_VAL_INT_PLUS_NANO:
 		if (val2 < 0)
-			return sprintf(buf, "-%d.%09u\n", val, -val2);
+			return sprintf(buf, "-%d.%09u\n", (int)abs(val), -val2);
 		else
 			return sprintf(buf, "%d.%09u\n", val, val2);
 	case IIO_VAL_FRACTIONAL:
-- 
1.7.9.5

Re: [PATCH] iio: core: Avoid double minus in sysfs output

[Jonathan Cameron]

On 07/22/13 12:16, Oleksandr Kravchenko wrote:
> From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
> 
> This patch fixes the issue with double minus in output when
> reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
> IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
> both are negatives output string contains "--" before
> digits. It is result of "-%d..." in sprintf() format.
> 
> Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Applied to the togreg branch of iio.git

Not taken this as a fix as I don't know of any current drivers where this will
be a problem.

Thanks.
> ---
>  drivers/iio/industrialio-core.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index d56d122..97f0297 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -383,14 +383,14 @@ static ssize_t iio_read_channel_info(struct device *dev,
>  		scale_db = true;
>  	case IIO_VAL_INT_PLUS_MICRO:
>  		if (val2 < 0)
> -			return sprintf(buf, "-%d.%06u%s\n", val, -val2,
> +			return sprintf(buf, "-%ld.%06u%s\n", abs(val), -val2,
>  				scale_db ? " dB" : "");
>  		else
>  			return sprintf(buf, "%d.%06u%s\n", val, val2,
>  				scale_db ? " dB" : "");
>  	case IIO_VAL_INT_PLUS_NANO:
>  		if (val2 < 0)
> -			return sprintf(buf, "-%d.%09u\n", val, -val2);
> +			return sprintf(buf, "-%ld.%09u\n", abs(val), -val2);
>  		else
>  			return sprintf(buf, "%d.%09u\n", val, val2);
>  	case IIO_VAL_FRACTIONAL:
> 

[PATCH] iio: core: Avoid double minus in sysfs output

[Oleksandr Kravchenko]

From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>

This patch fixes the issue with double minus in output when
reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
both are negatives output string contains "--" before
digits. It is result of "-%d..." in sprintf() format.

Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
---
 drivers/iio/industrialio-core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index d56d122..97f0297 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -383,14 +383,14 @@ static ssize_t iio_read_channel_info(struct device *dev,
 		scale_db = true;
 	case IIO_VAL_INT_PLUS_MICRO:
 		if (val2 < 0)
-			return sprintf(buf, "-%d.%06u%s\n", val, -val2,
+			return sprintf(buf, "-%ld.%06u%s\n", abs(val), -val2,
 				scale_db ? " dB" : "");
 		else
 			return sprintf(buf, "%d.%06u%s\n", val, val2,
 				scale_db ? " dB" : "");
 	case IIO_VAL_INT_PLUS_NANO:
 		if (val2 < 0)
-			return sprintf(buf, "-%d.%09u\n", val, -val2);
+			return sprintf(buf, "-%ld.%09u\n", abs(val), -val2);
 		else
 			return sprintf(buf, "%d.%09u\n", val, val2);
 	case IIO_VAL_FRACTIONAL:
-- 
1.7.9.5

Re: [PATCH] iio: core: Avoid double minus in sysfs output

[Oleksandr Kravchenko]

Please ignore this patch for now. I'll rework it soon. It issues
warnings when compiling.

On Sat, Jul 20, 2013 at 12:06 AM, Jonathan Cameron <jic23@kernel.org> wrote:
> On 07/19/2013 07:15 AM, Oleksandr Kravchenko wrote:
>> On Thu, Jul 18, 2013 at 7:24 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>>> On 07/18/2013 05:47 PM, Oleksandr Kravchenko wrote:
>>>> From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
>>>>
>>>> This patch fixes the issue with double minus in output when
>>>> reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
>>>> IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
>>>> both are negatives output string contains "--" before
>>>> digits. It is result of "-%d..." in sprintf() format.
>>>>
>>>
>>> Hm, this might be a bug in a driver that is triggering this. The idea is
>>> that val2 is only allowed to be negative if val is 0.
>>>
>>> - Lars
>>>
>> If I calculate val and val2 in next way:
>> *val = adc / 1000000;
>> *val2 = adc % 1000000;
>> both val and val2 could by negative. Do I have to check it in my driver?
>>
> I guess it is will happen occasionally.  In the c89 standard, module for a negative
> is implementation specific.  Anyone know if we can assume this will work in all cases
> within the kernel?



-- 
Oleksandr Kravchenko
GlobalLogic
P +380633213187
P +380994930248
www.globallogic.com

http://www.globallogic.com/email_disclaimer.txt

Re: [PATCH] iio: core: Avoid double minus in sysfs output

[Jonathan Cameron]

On 07/19/2013 07:15 AM, Oleksandr Kravchenko wrote:
> On Thu, Jul 18, 2013 at 7:24 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>> On 07/18/2013 05:47 PM, Oleksandr Kravchenko wrote:
>>> From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
>>>
>>> This patch fixes the issue with double minus in output when
>>> reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
>>> IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
>>> both are negatives output string contains "--" before
>>> digits. It is result of "-%d..." in sprintf() format.
>>>
>>
>> Hm, this might be a bug in a driver that is triggering this. The idea is
>> that val2 is only allowed to be negative if val is 0.
>>
>> - Lars
>>
> If I calculate val and val2 in next way:
> *val = adc / 1000000;
> *val2 = adc % 1000000;
> both val and val2 could by negative. Do I have to check it in my driver?
> 
I guess it is will happen occasionally.  In the c89 standard, module for a negative
is implementation specific.  Anyone know if we can assume this will work in all cases
within the kernel?

Re: [PATCH] iio: core: Avoid double minus in sysfs output

[Oleksandr Kravchenko]

On Thu, Jul 18, 2013 at 7:24 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 07/18/2013 05:47 PM, Oleksandr Kravchenko wrote:
>> From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
>>
>> This patch fixes the issue with double minus in output when
>> reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
>> IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
>> both are negatives output string contains "--" before
>> digits. It is result of "-%d..." in sprintf() format.
>>
>
> Hm, this might be a bug in a driver that is triggering this. The idea is
> that val2 is only allowed to be negative if val is 0.
>
> - Lars
>
If I calculate val and val2 in next way:
*val = adc / 1000000;
*val2 = adc % 1000000;
both val and val2 could by negative. Do I have to check it in my driver?

Re: [PATCH] iio: core: Avoid double minus in sysfs output

[Lars-Peter Clausen]

On 07/18/2013 05:47 PM, Oleksandr Kravchenko wrote:
> From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
> 
> This patch fixes the issue with double minus in output when
> reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
> IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
> both are negatives output string contains "--" before
> digits. It is result of "-%d..." in sprintf() format.
> 

Hm, this might be a bug in a driver that is triggering this. The idea is
that val2 is only allowed to be negative if val is 0.

- Lars

> Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
> ---
>  drivers/iio/industrialio-core.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index d56d122..b3d3959 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -383,14 +383,14 @@ static ssize_t iio_read_channel_info(struct device *dev,
>  		scale_db = true;
>  	case IIO_VAL_INT_PLUS_MICRO:
>  		if (val2 < 0)
> -			return sprintf(buf, "-%d.%06u%s\n", val, -val2,
> +			return sprintf(buf, "-%d.%06u%s\n", abs(val), -val2,
>  				scale_db ? " dB" : "");
>  		else
>  			return sprintf(buf, "%d.%06u%s\n", val, val2,
>  				scale_db ? " dB" : "");
>  	case IIO_VAL_INT_PLUS_NANO:
>  		if (val2 < 0)
> -			return sprintf(buf, "-%d.%09u\n", val, -val2);
> +			return sprintf(buf, "-%d.%09u\n", abs(val), -val2);
>  		else
>  			return sprintf(buf, "%d.%09u\n", val, val2);
>  	case IIO_VAL_FRACTIONAL:
> 

[PATCH] iio: core: Avoid double minus in sysfs output

[Oleksandr Kravchenko]

From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>

This patch fixes the issue with double minus in output when
reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
both are negatives output string contains "--" before
digits. It is result of "-%d..." in sprintf() format.

Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
---
 drivers/iio/industrialio-core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index d56d122..b3d3959 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -383,14 +383,14 @@ static ssize_t iio_read_channel_info(struct device *dev,
 		scale_db = true;
 	case IIO_VAL_INT_PLUS_MICRO:
 		if (val2 < 0)
-			return sprintf(buf, "-%d.%06u%s\n", val, -val2,
+			return sprintf(buf, "-%d.%06u%s\n", abs(val), -val2,
 				scale_db ? " dB" : "");
 		else
 			return sprintf(buf, "%d.%06u%s\n", val, val2,
 				scale_db ? " dB" : "");
 	case IIO_VAL_INT_PLUS_NANO:
 		if (val2 < 0)
-			return sprintf(buf, "-%d.%09u\n", val, -val2);
+			return sprintf(buf, "-%d.%09u\n", abs(val), -val2);
 		else
 			return sprintf(buf, "%d.%09u\n", val, val2);
 	case IIO_VAL_FRACTIONAL:
-- 
1.7.9.5