Re: [PATCH 1/2] staging:iio:adc:added space around '-'

From: Jonathan Cameron
Date: Sun Jan 24 2016 - 11:36:25 EST


On 20/01/16 14:21, Dan Carpenter wrote:
> On Fri, Jan 15, 2016 at 09:15:52PM +0100, Lars-Peter Clausen wrote:
>> On 01/15/2016 08:42 PM, Bhumika Goyal wrote:
>>> This patch adds apace around '-' operator.Found using checkpatch.pl
>>>
>>> Signed-off-by: Bhumika Goyal <bhumirks@xxxxxxxxx>
>>> ---
>>> drivers/staging/iio/adc/ad7280a.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/staging/iio/adc/ad7280a.c b/drivers/staging/iio/adc/ad7280a.c
>>> index f45ebed..0c73bce 100644
>>> --- a/drivers/staging/iio/adc/ad7280a.c
>>> +++ b/drivers/staging/iio/adc/ad7280a.c
>>> @@ -744,14 +744,14 @@ out:
>>> }
>>>
>>> static IIO_DEVICE_ATTR_NAMED(in_thresh_low_value,
>>> - in_voltage-voltage_thresh_low_value,
>>> + in_voltage - voltage_thresh_low_value,
>>
>> Hi,
>>
>> Thanks for patch. But when sending cleanup patches like this please make
>> sure that you a) understand what the code does and how your change affects
>> it and b) as a bare minimum of testing perform a compile test, if possible
>> also do functional testing.
>>
>> The patch as it is, is neither semantically nor syntactically correct. As an
>> exercise please make sure you understand why.
>
> Ugh!
>
> It took me a long time to figure out the bug in this patch... Why does
> that filename have a mix of dashes and underscores? Too late to fix it
> now... :/
>
Very deliberately. The - is indicating it is a differential channel!
Literally A minus B.

It's an awfully compact representation for maths ;)
This is obscured partly in this case as it's specifying an attribute
shared by a set of differential channels so it's the generalization
of
in_voltage0-voltage1_thresh_low_value
which does begin to slightly stretch the argument that it is nice and
clear ;(

Jonathan
> regards,
> dan carpenter
>
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