[Outreachy kernel] Re: [PATCH] Staging: iio: adc: Added Space around binary op.

[Julia Lawall]

On Fri, 8 Sep 2017, Lars-Peter Clausen wrote:

> On 09/08/2017 11:32 AM, Jonathan Cameron wrote:
> > On Fri, 8 Sep 2017 07:29:06 +0100
> > Jonathan Cameron <jic23 at jic23.retrosnub.co.uk> wrote:
> >
> >> On 8 September 2017 05:47:52 BST, Himanshi Jain <himshijain.hj at gmail.com> wrote:
> >>> Added space around(one on each side of) binary
> >>> operator(-) as preferred according to kernel
> >>> coding style.
> >>>
> >>> Signed-off-by: Himanshi Jain <himshijain.hj at gmail.com>
> >>
> >> Take a closer look at that macro. It isn't doing what you think...
> >> To give a hint, changing this breaks userspace.
> >
> > Ok, I'm bored of this particular one coming up. When you have
> > worked out what is going on Himanshi, would you mind putting
> > together a patch adding a comment describing why it is a bad
> > idea to 'fix' this?  That would be a very useful patch as
> > far as I'm concerned :)
> >
> > There aren't that many cases of this in IIO so adding a comment
> > on each of them is probably reasonable just to avoid wasting
> > people's time on fixing them! (I think we have had more than
> > 5 such goes this year so far...)
> >
>
> I'd much rather fix this API so that you have to put "" around the name so
> that it is clear that it is a string, rather than doing the implicit
> conversion to string using preprocessor magic. Better to have a
> self-documenting API then having to add a comment to each user of the API.

All the DEVICE_ATTR macros use the same strategy.  And the non-IIO ones,
eg DEVICE_ATTR_RW, also use the provided name to construct the names of
the show and store functions, so I don't think a string would be
appropriate.

julia

>
> > Jonathan
> >
> >>
> >> Jonathan
> >>
> >>
> >>> ---
> >>> drivers/staging/iio/adc/ad7192.c | 2 +-
> >>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/staging/iio/adc/ad7192.c
> >>> b/drivers/staging/iio/adc/ad7192.c
> >>> index d11c6de..1aee662 100644
> >>> --- a/drivers/staging/iio/adc/ad7192.c
> >>> +++ b/drivers/staging/iio/adc/ad7192.c
> >>> @@ -341,7 +341,7 @@ static int ad7192_setup(struct ad7192_state *st,
> >>> }
> >>>
> >>> static IIO_DEVICE_ATTR_NAMED(in_v_m_v_scale_available,
> >>> -			     in_voltage-voltage_scale_available,
> >>> +			     in_voltage - voltage_scale_available,
> >>> 			     0444, ad7192_show_scale_available, NULL, 0);
> >>>
> >>> static IIO_DEVICE_ATTR(in_voltage_scale_available, 0444,
> >>
> >
>
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