Messages in this thread | | | From | Andy Shevchenko <> | Date | Tue, 27 Dec 2022 20:30:33 +0200 | Subject | Re: drivers/gpio/gpio-exar.c:52 exar_offset_to_sel_addr() warn: replace divide condition 'pin / 8' with 'pin >= 8' |
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On Tue, Dec 27, 2022 at 7:46 PM Dan Carpenter <error27@gmail.com> wrote: > On Sun, Dec 25, 2022 at 12:50:46PM +0100, Andy Shevchenko wrote: > > > Andy Shevchenko <andy.shevchenko@gmail.com> kirjoitti 25.12.2022 kello 12.45: > > >>> Dan Carpenter <error27@gmail.com> kirjoitti 24.12.2022 kello 20.30: > > >>> On Sat, Dec 24, 2022 at 05:19:27PM +0100, Andy Shevchenko wrote: > > >>>> Dan Carpenter <error27@gmail.com> kirjoitti 23.12.2022 kello 11.54:
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> > >>>> smatch warnings: > > >>>> drivers/gpio/gpio-exar.c:52 exar_offset_to_sel_addr() warn: replace divide condition 'pin / 8' with 'pin >= 8' > > >>>> drivers/gpio/gpio-exar.c:62 exar_offset_to_lvl_addr() warn: replace divide condition 'pin / 8' with 'pin >= 8' > > >>> > > >>> I don’t think this is a good advice. If we want to limit that, we need > > >>> to check also upper limit. But. The GPIO framework does that. So, > > >>> changing / to >= is bogus. > > >> > > >> How is checking pin / 8 not mathematically equivalent to pin >= 8? > > > > > > The point is that semantically the / is better in case this code will ever support more than two banks of pins. > > > > On top of that it’s paired with pin % 8. > > I noticed that, but it's a common bug though that a lot of people > accidentally write if (pin / 8) when if ((pin % 8) == 0) is intended.
Probably. Here the pin/8 is the correct approach, it shows the bank number, where each bank is out of 8 pins.
> For example:
Thanks, but it's unrelated to this case.
-- With Best Regards, Andy Shevchenko
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