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From: Gregory CLEMENT <gregory.clement@free-electrons.com>
To: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
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        Adrian Hunter <adrian.hunter@intel.com>,
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Subject: Re: [PATCH v2] mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock
References: <20170929130435.6805-1-gregory.clement@free-electrons.com>
        <20170930104109.60853202@xhacker.debian>
        <20170930080710.119c0258@windsurf>
        <20170930141753.7c4e34ea@xhacker.debian>
Date: Mon, 02 Oct 2017 16:32:23 +0200
In-Reply-To: <20170930141753.7c4e34ea@xhacker.debian> (Jisheng Zhang's message
        of "Sat, 30 Sep 2017 14:17:53 +0800")
Message-ID: <87fub1mxhk.fsf@free-electrons.com>
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Sender: stable-owner@vger.kernel.org
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Hi Jisheng,
 
 On sam., sept. 30 2017, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote:

> Hi Thomas,
>
> On Sat, 30 Sep 2017 08:07:10 +0200 Thomas Petazzoni wrote:
>
>> Hello,
>> 
>> On Sat, 30 Sep 2017 10:41:09 +0800, Jisheng Zhang wrote:
>> 
>> > > +	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
>> > > +	if (IS_ERR(priv->axi_clk)) {
>> > > +		err = PTR_ERR(priv->axi_clk);
>> > > +		if (err == -EPROBE_DEFER)
>> > > +			goto err_clk;
>> > > +		priv->axi_clk = NULL;    
>> > 
>> > IMHO, this assignment could be removed. What do you think?  
>> 
>> No, because if the clock is not present in the Device Tree,
>> priv->axi_clk will contain an error code encoded as a pointer, so
>> priv->axi_clk will not be NULL. Hence the rest of the code that will
>
> FWICT, the clk_disable_unprepare() could also check whether the clk
> is err, am I wrong?

You're right, I've jsut checked it.
So I will remove it to have a smaller fix.

Thanks,

Gregory

>
>> operate on this clock will believe there is a valid clock pointed by
>> priv->axi_clk. So we really want to reset it to NULL when there was an
>> error getting the clock.
>> 
>> Best regards,
>> 
>> Thomas
>

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com