linux-kernel - Re: [PATCH] i2c: designwear: Fix clk warning on suspend/resume

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Date:   Mon, 6 Feb 2017 11:32:46 +0200
From:   Jarkko Nikula <jarkko.nikula@...ux.intel.com>
To:     John Stultz <john.stultz@...aro.org>,
        lkml <linux-kernel@...r.kernel.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org
Subject: Re: [PATCH] i2c: designwear: Fix clk warning on suspend/resume

Hi

On 04.02.2017 01:01, John Stultz wrote:
> On my HiKey board, I'm seeing clk warnings on suspend/resume, which
> seem to be caused by runtime pm suspending the device, then the same
> suspend hook being called again on suspend time.
>
> Thus this patch adds suspend state tracking to avoid runtime pm and
> suspend causing double suspend calls on i2c-designware-platdrv.
>
> Feedback would be greatly appreciated!
>
> Cc: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Cc: Wolfram Sang <wsa@...-dreams.de>
> Cc: linux-i2c@...r.kernel.org
> Signed-off-by: John Stultz <john.stultz@...aro.org>
> ---
>  drivers/i2c/busses/i2c-designware-core.h    | 1 +
>  drivers/i2c/busses/i2c-designware-platdrv.c | 9 +++++++++
>  2 files changed, 10 insertions(+)
>
...
> @@ -340,8 +340,12 @@ static int dw_i2c_plat_suspend(struct device *dev)
>  	struct platform_device *pdev = to_platform_device(dev);
>  	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
>
> +	if (i_dev->suspended)
> +		return 0;
> +
>  	i2c_dw_disable(i_dev);
>  	i2c_dw_plat_prepare_clk(i_dev, false);
> +	i_dev->suspended = true;
>
This feels a band-aid fix. At quick look some drivers appear to use 
SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 
pm_runtime_force_resume) in their dev_pm_ops.

Could you try does it help in your case and I'll check our platforms.

-- 
Jarkko