linux-kernel - Re: [PATCH] ASoC: samsung: i2s: Check before clk

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Date:   Fri, 10 Jun 2022 21:52:55 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Yihao Han <hanyihao@...o.com>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: samsung: i2s: Check before clk_unregister() not
 needed

On 10/06/2022 18:15, Christophe JAILLET wrote:
> Le 29/05/2022 à 10:06, Krzysztof Kozlowski a écrit :
>> On 27/05/2022 08:54, Yihao Han wrote:
>>> clk_unregister() already checks the clk ptr using
>>> !clk || WARN_ON_ONCE(IS_ERR(clk)) so there is no need to check it
>>> again before calling it.
>>>
>>
>> No, this explanation does not make sense. clk_unregister() warns and
>> this code is not equivalent.
>>
>>
>>
>> Best regards,
>> Krzysztof
>>
> 
> Hi,
> 
> Moreover, as pointed out by greg in [1] on some plateform the assertion 
> in the commit description is wrong. His message is about clk_disable() 
> but, IIUC, it makes sense for clk_unregister() as well. See [2] on the 
> sh plateform.
> 

Yes, this is true as well, although does not have the practical impact
on this driver as it uses platforms with common clock framework.


Best regards,
Krzysztof