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

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Message-ID: <56AF69D3.4070300@linux.intel.com>
Date:	Mon, 1 Feb 2016 16:21:07 +0200
From:	Jarkko Nikula <jarkko.nikula@...ux.intel.com>
To:	Alexey Khoroshilov <khoroshilov@...ras.ru>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	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 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.

-- 
Jarkko