linux-kernel - Re: [PATCH] spi: sun4i: disable clocks in the remove function

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Message-ID: <20171206152005.yfbyylu6tbe5gnnv@flea.lan>
Date:   Wed, 6 Dec 2017 16:20:05 +0100
From:   Maxime Ripard <maxime.ripard@...e-electrons.com>
To:     Takuo Koguchi <takuo.koguchi@...il.com>
Cc:     lkml@...r.kernel.org, khoroshilov@...ras.ru,
        takuo.koguchi.sw@...il.com,
        Takuo Koguchi <takuo.koguchi.sw@...achi.com>,
        Mark Brown <broonie@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        linux-spi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: sun4i: disable clocks in the remove function

Hi,

On Thu, Dec 07, 2017 at 12:22:13AM +0900, Takuo Koguchi wrote:
> mclk and hclk need to be disabled explicitly since pm_runtime_disable does
> not disable the clocks.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Takuo Koguchi <takuo.koguchi.sw@...achi.com>
> ---
>  drivers/spi/spi-sun4i.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
> index c5cd635..9011c09 100644
> --- a/drivers/spi/spi-sun4i.c
> +++ b/drivers/spi/spi-sun4i.c
> @@ -525,6 +525,11 @@ static int sun4i_spi_probe(struct platform_device *pdev)
>  
>  static int sun4i_spi_remove(struct platform_device *pdev)
>  {
> +	struct spi_master *master = dev_get_drvdata(&pdev->dev);
> +	struct sun4i_spi *sspi = spi_master_get_devdata(master);
> +
> +	clk_disable_unprepare(sspi->mclk);
> +	clk_disable_unprepare(sspi->hclk);

And that will in turn create an unbalanced disable call if suspend was
called before the remove, which is very likely.

Why are you not calling pm_runtime_force_suspend? How did you test
that patch?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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