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Date:   Thu, 25 May 2023 08:05:58 +0300
From:   Dan Carpenter <dan.carpenter@linaro.org>
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc:     Wang Zhang <silver_code@hust.edu.cn>,
        Peter Korsgaard <peter@korsgaard.com>,
        Andrew Lunn <andrew@lunn.ch>,
        hust-os-kernel-patches@googlegroups.com, linux-i2c@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] i2c: ocores: use devm_ managed clks
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References: <5572a733.abc0.18846f13b0b.Coremail.m202171703@hust.edu.cn>
 <20230524154318.2259-1-silver_code@hust.edu.cn>
 <68c4b991-6af9-36e8-354c-7c3b232ba4c2@wanadoo.fr>
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On Wed, May 24, 2023 at 09:21:56PM +0200, Christophe JAILLET wrote:
> > +	if (ret) {
> > +		dev_err(dev,
> > +			"clk_prepare_enable failed: %d\n", ret);
> > +		return ret;
> >   	}
> > +	rate = clk_get_rate(i2c->clk) / 1000;
> 
> Now (because of the devm_clk_get_optional_enabled()), i2c->clk can be NULL,
> so this would deference a NULL pointer.
> 

No, it's fine.  clk_get_rate() checks for NULL.  When a function returns
a mix of error pointers and NULL, like devm_clk_get_optional_enabled(),
then all the functions like this must have NULL checks built it.

regards,
dan carpenter