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

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Message-ID: <1454337845.32507.20.camel@linux.intel.com>
Date:	Mon, 01 Feb 2016 16:44:05 +0200
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
	Alexey Khoroshilov <khoroshilov@...ras.ru>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:	Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, ldv-project@...uxtesting.org
Subject: Re: [PATCH] i2c: designware: balance clk enable/disable on removal

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@...ras.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@...ux.intel.com>
Intel Finland Oy