linux-kernel - Re: [PATCH] mmc: sdhci-of-arasan: Disable clk

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Date:   Tue, 12 Dec 2017 09:15:14 -0800
From:   Flavio Ceolin <flavio.ceolin@...el.com>
To:     Michal Simek <michal.simek@...inx.com>,
        linux-kernel@...r.kernel.org
Cc:     Michal Simek <michal.simek@...inx.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "moderated list\:ARM\/ZYNQ ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        "open list\:SECURE DIGITAL HOST CONTROLLER INTERFACE \(SDHCI...\)" 
        <linux-mmc@...r.kernel.org>
Subject: Re: [PATCH] mmc: sdhci-of-arasan: Disable clk_xin clock in the remove

Hi Michal,

> On 12.12.2017 09:19, Flavio Ceolin wrote:
>> clk_xin is properly prepared/enabled on sdhci_arasan_probe(), and
>> unprepared/disabled in the error path, but it is not being
>> unprepared/disabled on sdhci_arasan_remove().
>> 
>> Found by Linux Driver Verification project (linuxtesting.org).
>> 
>> Signed-off-by: Flavio Ceolin <flavio.ceolin@...el.com>
>> ---
>>  drivers/mmc/host/sdhci-of-arasan.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>> 
>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>> index 0720ea7..69bd260 100644
>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>> @@ -692,6 +692,7 @@ static int sdhci_arasan_remove(struct platform_device *pdev)
>>  	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>  	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
>>  	struct clk *clk_ahb = sdhci_arasan->clk_ahb;
>> +	struct clk *clk_xin = devm_clk_get(&pdev->dev, "clk_xin");
>
> I don't think this is right. You have already asked for this clock in
> probe. It means you should reuse pltfm_host->clk = clk_xin;
>
> And if you look at sdhci_pltfm_unregister you will find out that
> clk_disable_unprepare(pltfm_host->clk);
> is called there.

Yep, I confirm that. You're right, the patch is wrong, sorry for that :)
>
>>  
>>  	if (!IS_ERR(sdhci_arasan->phy)) {
>>  		if (sdhci_arasan->is_phy_on)
>> @@ -705,6 +706,9 @@ static int sdhci_arasan_remove(struct platform_device *pdev)
>>  
>>  	clk_disable_unprepare(clk_ahb);
>>  
>> +	if (!IS_ERR(clk_xin))
>
> And clk_xin is required property.
>
>> +		clk_disable_unprepare(clk_xin);
>> +
>>  	return ret;
>>  }
>>  
>> 
>
> It means NACK from me.
>
> Thanks,
> Michal

Regards,
Flavio Ceolin