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

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Date:   Fri, 10 Jun 2022 18:15:25 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        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

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.

CJ

[1]: https://lore.kernel.org/all/YqMIUOTU%2Fk5XpW3I@kroah.com/
[2]: 
https://elixir.bootlin.com/linux/v5.18.3/source/drivers/sh/clk/core.c#L452