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Subject: Re: [PATCH] driver core: platform: Rename platform_get_irq_optional()
 to platform_get_irq_silent()
To:     =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>
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From:   Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <cd89d952-b7a6-cd37-9df3-f3565cb2f802@omp.ru>
Date:   Sat, 15 Jan 2022 16:08:52 +0300
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Precedence: bulk

On 1/14/22 11:29 PM, Uwe Kleine-K?nig 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.

  Ah! OK then. :-)

>>> Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.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-K?nig 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...
> 
> Yes, I didn't count you to the three people signaling agreement.

   :-D

>> [...]
>>> 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.

   Not sure I share the sentiment but good to know about that.

> Best regards
> Uwe

MBR, Sergey