[RFC] spi: sun6i: disable/unprepare clocks on remove

[RFC] spi: sun6i: disable/unprepare clocks on remove

[Tobias Jordan]

sun6i_spi_probe() uses sun6i_spi_runtime_resume() to prepare/enable clocks,
so sun6i_spi_remove() should use sun6i_spi_runtime_suspend() to
disable/unprepare them.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: 3558fe900e8af spi: sunxi: Add Allwinner A31 SPI controller driver
Signed-off-by: Tobias Jordan <Tobias.Jordan@elektrobit.com>
---
This was found by LDV, and it looks very suspicious to me, but I'm not
sure if the fix is that easy. Is suspend() called automatically when the
driver is removed? If not, is it correct to unconditionally call
suspend(), or should there be a check for the PM state instead?

 drivers/spi/spi-sun6i.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
index fb38234249a8..5e5df09e5d04 100644
--- a/drivers/spi/spi-sun6i.c
+++ b/drivers/spi/spi-sun6i.c
@@ -541,6 +541,7 @@ static int sun6i_spi_probe(struct platform_device *pdev)
 
 static int sun6i_spi_remove(struct platform_device *pdev)
 {
+	sun6i_spi_runtime_suspend(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
 	return 0;
-- 
2.11.0

Re: [RFC] spi: sun6i: disable/unprepare clocks on remove

[Maxime Ripard]

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Hi Tobias,

On Wed, Dec 06, 2017 at 01:50:29PM +0100, Tobias Jordan wrote:
> sun6i_spi_probe() uses sun6i_spi_runtime_resume() to prepare/enable clocks,
> so sun6i_spi_remove() should use sun6i_spi_runtime_suspend() to
> disable/unprepare them.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Fixes: 3558fe900e8af spi: sunxi: Add Allwinner A31 SPI controller driver
> Signed-off-by: Tobias Jordan <Tobias.Jordan@elektrobit.com>
> ---
> This was found by LDV, and it looks very suspicious to me, but I'm not
> sure if the fix is that easy. Is suspend() called automatically when the
> driver is removed? If not, is it correct to unconditionally call
> suspend(), or should there be a check for the PM state instead?
> 
>  drivers/spi/spi-sun6i.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
> index fb38234249a8..5e5df09e5d04 100644
> --- a/drivers/spi/spi-sun6i.c
> +++ b/drivers/spi/spi-sun6i.c
> @@ -541,6 +541,7 @@ static int sun6i_spi_probe(struct platform_device *pdev)
>  
>  static int sun6i_spi_remove(struct platform_device *pdev)
>  {
> +	sun6i_spi_runtime_suspend(&pdev->dev);

Yeah, that's not ideal. The best solution would be to call
pm_runtime_force_suspend I guess.

Maxime

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

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