linux-kernel - Re: [RFC PATCH 4/5] iio: accel: Support Kionix/ROHM KX022A accelerometer

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Message-ID: <e3abc0a9-ad5b-f6ef-8cba-0b4c6c8325c0@gmail.com>
Date:   Wed, 28 Sep 2022 19:23:06 +0300
From:   Matti Vaittinen <mazziesaccount@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>,
        Cosmin Tanislav <demonsingur@...il.com>,
        Jagath Jog J <jagathjog1996@...il.com>,
        linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Mutanen, Mikko" <Mikko.Mutanen@...rohmeurope.com>,
        "Haikola, Heikki" <Heikki.Haikola@...rohmeurope.com>
Subject: Re: [RFC PATCH 4/5] iio: accel: Support Kionix/ROHM KX022A
 accelerometer

Hi Andy,

On 9/28/22 17:06, Andy Shevchenko wrote:
> On Wed, Sep 28, 2022 at 02:14:14PM +0300, Matti Vaittinen wrote:
>> On 9/22/22 20:03, Jonathan Cameron wrote:
>>> On Wed, 21 Sep 2022 14:45:35 +0300
> 
> ...
> 
>>>> +		dev_err(dev, "no regmap\n");
>>>
>>> Use dev_err_probe() for all dev_err() stuff in probe paths.
>>> It ends up cleaner and we don't care about the tiny overhead
>>> of checking for deferred.
>>
>> This one bothers me a bit. It just does not feel correct to pass -EINVAL for
>> the dev_err_probe() so the dev_err_probe() can check if -EINVAL !=
>> -EPROBE_DEFER. I do understand perfectly well the consistent use of
>> dev_err_probe() for all cases where we get an error-code from a function and
>> return it - but using dev_err_probe() when we hard-code the return value in
>> code calling the dev_err_probe() does not feel like "the right thing to do"
>> (tm).
>>
>> Eg, I agree that
>> return dev_err_probe(dev, ret, "bar");
>> is nice even if we know the function that gave us the "ret" never requests
>> defer (as that can change some day).
>>
>> However, I don't like issuing:
>> return dev_err_probe(dev, -EINVAL, "bar");
> 
> This case specifically was added into documentation by 7065f92255bb ("driver
> core: Clarify that dev_err_probe() is OK even w/out -EPROBE_DEFER").

Yes. And this is exactly what I meant with:
 >> Eg, I agree that
 >> return dev_err_probe(dev, ret, "bar");
 >> is nice even if we know the function that gave us the "ret" never 
requests
 >> defer

There is still (in my opinion) a significant difference if we call:
 >> return dev_err_probe(dev, -EINVAL, "bar");

- where we really hard-code the -EINVAL as a parameter to the 
dev_err_probe()

>> Well, please let me know if you think the dev_err_probe() should be used
>> even in cases where we hard code the return to something...
> 
> And this should be, of course, maintainer's decision.

Ultimately, yes.

Best Regards
	--Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~