Re: [PATCH] irqchip/renesas-irqc: Use platform_get_irq_optional() to get the interrupt

[Geert Uytterhoeven]

Hi Andy,

On Sun, Dec 26, 2021 at 9:49 AM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
> On Sun, Dec 26, 2021 at 1:59 AM Lad, Prabhakar
> <prabhakar.csengg@xxxxxxxxx> wrote:
> > On Sat, Dec 25, 2021 at 5:40 PM Andy Shevchenko
> > <andy.shevchenko@xxxxxxxxx> wrote:
> > > On Sat, Dec 25, 2021 at 7:28 PM Lad, Prabhakar
> > > <prabhakar.csengg@xxxxxxxxx> wrote:
> > > > On Sat, Dec 25, 2021 at 4:46 PM Andy Shevchenko
> > > > <andy.shevchenko@xxxxxxxxx> wrote:
> > > > > On Thu, Dec 16, 2021 at 9:52 AM Lad Prabhakar
> > > > > <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> wrote:
> > >
> > > > > ret = platform_get_irq_optional(...);
> > > > > if (ret < 0 && ret != -ENXIO)
> > > > >   return ret;
> > > > > if (ret > 0)
> > > > >   ...we got it...
> > > > >
> > > > > It will allow the future API fix of platform_get_irq_optional() to be
> > > > > really optional.
> > > > >
> > > > Later patch [0] (merged into -next) does check for -ENXIO first.
> > > >
> > > > [0] https://lore.kernel.org/lkml/20211216182121.5323-1-prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx/t/
> > >
> > > The problem is that it doesn't consider 0 as no IRQ.
> > >
> > Can you please point me to the discussion/patch where this API change
> > is considered/discussed. Just to clarify now the new API for
> > platform_get_irq_optional() will return "0" in case there is no
> > interrupt and not not -ENXIO anymore?
>
> The longest one happened here:
> https://lore.kernel.org/linux-ide/20211209145937.77719-1-andriy.shevchenko@xxxxxxxxxxxxxxx/T/#u
>
> It has links to some other discussions on the topic.
>
> > When will this patch be merged for the new api, so that I can base my
> > patches on top of it to avoid more changes?
>
> You can simply imply that, I dunno when it gets merged (from my point
> of view the users should be fixed first, and since you are adding
> users, the burden is increasing).

Not only users (drivers), but also providers (architecture-specific code).
IRQ zero is still valid on some architectures, e.g. on SH[1].

[1] https://lore.kernel.org/linux-renesas-soc/CAMuHMdUg3=q7gyaVHP0XcYUOo3PQUUv8Hc8wp5faVQ+bTBpg4A@xxxxxxxxxxxxxx/

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds