Date:   Fri, 14 Jan 2022 22:45:38 +0300
From:   Sergey Shtylyov <s.shtylyov@....ru>
To:     Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
        "Mark Brown" <broonie@...nel.org>
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Subject: Re: [PATCH] driver core: platform: Rename platform_get_irq_optional()
 to platform_get_irq_silent()

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... :-)

> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
> ---
> 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@pengutronix.de)
> 
>>> 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...
 
[...]
> 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?
   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...

>  extern int platform_irq_count(struct platform_device *);
>  extern int devm_platform_get_irqs_affinity(struct platform_device *dev,
>  					   struct irq_affinity *affd,
[...]
MBR, Sergey

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