Re: [Outreachy kernel] [PATCH 3/3] staging: iio: adc: ad7192: Reformat lines crossing 80 columns

[Stefano Brivio <sbrivio@redhat.com>]

On Thu, 19 Mar 2020 00:40:02 +0530
Deepak R Varma <mh12gx2825@gmail.com> wrote:

> Macro arguments are computed at the time of calling the macro. This
> makes the lines cross 80 column width. Add variables to perform the
> calculations before hand and use these variable in the macro calls instead.
> 
> Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
> ---
>  drivers/staging/iio/adc/ad7192.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
> index a5b6cc1fc375..2a9c68aa8260 100644
> --- a/drivers/staging/iio/adc/ad7192.c
> +++ b/drivers/staging/iio/adc/ad7192.c
> @@ -480,14 +480,15 @@ static void ad7192_get_available_filter_freq(struct ad7192_state *st,
>  						    int *freq)
>  {
>  	unsigned int fadc;
> +	unsigned int sinc3_filter, sinc4_filter;
>  
>  	/* Formulas for filter at page 25 of the datasheet */
> -	fadc = DIV_ROUND_CLOSEST(st->fclk,
> -				 AD7192_SINC4_FILTER * AD7192_MODE_RATE(st->mode));
> +	sinc4_filter = AD7192_SINC4_FILTER * AD7192_MODE_RATE(st->mode);
> +	fadc = DIV_ROUND_CLOSEST(st->fclk, sinc4_filter);

The name sinc4_filter is at least not derived from another typo anymore,
but it still doesn't make sense to me. Is it a filtering... factor,
as the name would suggest? No. It comes from a "mode" register and it
becomes a divisor of the output data rate.

Besides, you don't need separate variables (why two, even?). As I
already mentioned to you offline, DIV_ROUND_CLOSEST() is used. If '/'
is the DIV_ROUND_CLOSEST() operation, then, I guess:

	a = b / (x * y) <=> a = b / x / y

-- 
Stefano