Re: [PATCH v2 2/2] iio: light: Add support for APDS9306 Light Sensor

[Matti Vaittinen]

On 10/31/23 15:42, Andy Shevchenko wrote:
> On Tue, Oct 31, 2023 at 02:07:46PM +0200, Matti Vaittinen wrote:
> > On 10/31/23 12:38, Andy Shevchenko wrote:
> > > On Tue, Oct 31, 2023 at 09:11:37AM +0200, Matti Vaittinen wrote:
> > > > On 10/30/23 12:21, Matti Vaittinen wrote:
> > > > > On 10/29/23 17:51, Matti Vaittinen wrote:
> > > > > > On 10/28/23 18:20, Jonathan Cameron wrote:
>
> ...
>
> > > > 	tmp = gts->max_scale;
> > > >
> > > > 	rem = do_div(tmp, total_gain);
> > > > 	if (total_gain > 1 && rem >= total_gain / 2)
> > > > 		tmp += 1ULL;
> > >
> > > ...which is NIH DIV_ROUND_CLOSEST_ULL()
> >
> > There is a difference though. The DIV_ROUND_CLOSEST_ULL() does
> >
> > tmp + total_gain / 2;
> >
> > before division - which in theory may overflow.
>
> Then you can fix it there for everybody, no?

Now that I know of this macro - Maybe. It's just always scary to touch 
things which seem like fundamental building blocks and which may be used 
by many. Odds are something breaks, so I tend to be very conservative 
when suggesting changes to widely used stuff. Especially when I have no 
idea when and why the API has been added - and if the thing I'm trying 
to "fix" has been a deliberate choice.

Yours,
	-- Matti.

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~