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

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Date:   Tue, 12 Dec 2017 10:37:22 +0100
From:   Michal Simek <michal.simek@...inx.com>
To:     Flavio Ceolin <flavio.ceolin@...el.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

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.

>  
>  	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