Re: [PATCH] i2c: designware: balance clk enable/disable on removal

From	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] i2c: designware: balance clk enable/disable on removal
Date	2016-02-01 15:50 +0100
Message-ID	<qXnXL-4fD-111@gated-at.bofh.it> (permalink)
References	<qWpRT-1uc-5@gated-at.bofh.it> <qXnEp-45e-81@gated-at.bofh.it>
Organization	Intel Finland Oy

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On Mon, 2016-02-01 at 16:21 +0200, Jarkko Nikula wrote:
> On 01/30/2016 12:31 AM, Alexey Khoroshilov wrote:
> > It seems clk_disable_unprepare() is missed in dw_i2c_plat_remove(),
> > so the patch adds it.
> > 
> > Found by Linux Driver Verification project (linuxtesting.org).
> > 
> > Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
> > ---
> >   drivers/i2c/busses/i2c-designware-platdrv.c | 1 +
> >   1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
> > b/drivers/i2c/busses/i2c-designware-platdrv.c
> > index 438f1b4964c0..8f19b7b81fe0 100644
> > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > @@ -267,6 +267,7 @@ static int dw_i2c_plat_remove(struct
> > platform_device *pdev)
> >   	i2c_del_adapter(&dev->adapter);
> > 
> >   	i2c_dw_disable(dev);
> > +	i2c_dw_plat_prepare_clk(dev, false);
> > 
> I tried this quickly and it appears more work is needed. When 
> CONFIG_PM_SLEEP is set then autosuspending will do the unprepare and 
> this patch causes double unprepare at remove. But when
> CONFIG_PM_SLEEP 
> is not set then indeed those clk calls are out of sync.

Besides that I would suggest to check carefully error patch in the
probe(), i.e. handling error from i2c_dw_probe(). There maybe similar
issue is hidden.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

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[PATCH] i2c: designware: balance clk enable/disable on removal Alexey Khoroshilov <khoroshilov@ispras.ru> - 2016-01-29 23:40 +0100
  Re: [PATCH] i2c: designware: balance clk enable/disable on removal Jarkko Nikula <jarkko.nikula@linux.intel.com> - 2016-02-01 15:30 +0100
    Re: [PATCH] i2c: designware: balance clk enable/disable on removal Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-02-01 15:50 +0100

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