Re: [PATCH] driver core: platform: Rename platform_get_irq_optional() to platform_get_irq_silent()

[Uwe Kleine-König]

On Fri, Jan 14, 2022 at 10:45:38PM +0300, Sergey Shtylyov wrote:
> On 1/13/22 10:43 PM, Uwe Kleine-König wrote:
> 
> > The subsystems regulator, clk and gpio have the concept of a dummy
> > resource. For regulator, clk and gpio there is a semantic difference
> > between the regular _get() function and the _get_optional() variant.
> > (One might return the dummy resource, the other won't. Unfortunately
> > which one implements which isn't the same for these three.) The
> > difference between platform_get_irq() and platform_get_irq_optional() is
> > only that the former might emit an error message and the later won't.
> > 
> > To prevent people's expectations that there is a semantic difference
> > between these too, rename platform_get_irq_optional() to
> > platform_get_irq_silent() to make the actual difference more obvious.
> > 
> > The #define for the old name can and should be removed once all patches
> > currently in flux still relying on platform_get_irq_optional() are
> > fixed.
> 
>    Hm... I'm afraid that with this #define they would never get fixed... :-)

I will care for it.

> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> > ---
> > Hello,
> > 
> > On Thu, Jan 13, 2022 at 02:45:30PM +0000, Mark Brown wrote:
> >> On Thu, Jan 13, 2022 at 12:08:31PM +0100, Uwe Kleine-König wrote:
> >>
> >>> This is all very unfortunate. In my eyes b) is the most sensible
> >>> sense, but the past showed that we don't agree here. (The most annoying
> >>> part of regulator_get is the warning that is emitted that regularily
> >>> makes customers ask what happens here and if this is fixable.)
> >>
> >> Fortunately it can be fixed, and it's safer to clearly specify things.
> >> The prints are there because when the description is wrong enough to
> >> cause things to blow up we can fail to boot or run messily and
> >> forgetting to describe some supplies (or typoing so they haven't done
> >> that) and people were having a hard time figuring out what might've
> >> happened.
> > 
> > Yes, that's right. I sent a patch for such a warning in 2019 and pinged
> > occationally. Still waiting for it to be merged :-\
> > (https://lore.kernel.org/r/20190625100412.11815-1-u.kleine-koenig@xxxxxxxxxxxxxx)
> > 
> >>> I think at least c) is easy to resolve because
> >>> platform_get_irq_optional() isn't that old yet and mechanically
> >>> replacing it by platform_get_irq_silent() should be easy and safe.
> >>> And this is orthogonal to the discussion if -ENOXIO is a sensible return
> >>> value and if it's as easy as it could be to work with errors on irq
> >>> lookups.
> >>
> >> It'd certainly be good to name anything that doesn't correspond to one
> >> of the existing semantics for the API (!) something different rather
> >> than adding yet another potentially overloaded meaning.
> > 
> > It seems we're (at least) three who agree about this. Here is a patch
> > fixing the name.
> 
>    I can't say I genrally agree with this patch...

Yes, I didn't count you to the three people signaling agreement.

> [...]
> > diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
> > index 7c96f169d274..6d495f15f717 100644
> > --- a/include/linux/platform_device.h
> > +++ b/include/linux/platform_device.h
> > @@ -69,7 +69,14 @@ extern void __iomem *
> >  devm_platform_ioremap_resource_byname(struct platform_device *pdev,
> >  				      const char *name);
> >  extern int platform_get_irq(struct platform_device *, unsigned int);
> > -extern int platform_get_irq_optional(struct platform_device *, unsigned int);
> > +extern int platform_get_irq_silent(struct platform_device *, unsigned int);
> > +
> > +/*
> > + * platform_get_irq_optional was recently renamed to platform_get_irq_silent.
> > + * Fixup users to not break patches that were created before the rename.
> > + */
> > +#define platform_get_irq_optional(pdev, index) platform_get_irq_silent(pdev, index)
> > +
> 
>    Yeah, why bother fixing if it compiles anyway?

The plan is to remove the define in one or two kernel releases. The idea
is only to not break patches that are currently in next.

>    I think an inline wrapper with an indication to gcc that the function is deprecated
> (I just forgot how it should look) would be better instead...

The deprecated function annotation is generally frowned upon. See
771c035372a0.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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