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From: Grygorii Strashko <grygorii.strashko@ti.com>
To: Baolin Wang <baolin.wang@linaro.org>, <wsa@the-dreams.de>
Cc: <broonie@kernel.org>, <linux-i2c@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called
Date: Mon, 9 Apr 2018 15:56:52 -0500	[thread overview]
Message-ID: <557074eb-e988-8ff5-bec0-c85bb9dcb8ec@ti.com> (raw)
In-Reply-To: <99031524fa147e72451d26f54b24f36093c0d3fa.1523255712.git.baolin.wang@linaro.org>



On 04/09/2018 01:40 AM, Baolin Wang wrote:
> Add one flag to indicate if the i2c controller has been in suspend state,
> which can prevent i2c accesses after i2c controller is suspended following
> system suspend.

This usually indicates some bigger problem - there should be no i2c access to
 the I2C driver once it's suspended. But if happens - 
it means suspend dependencies between drivers are broken or there some 
scheduling primitives are not disabled properly.
(possible sources - kthreads, delayed works, timers or even threaded irqs)

> 
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
>   drivers/i2c/busses/i2c-sprd.c |   16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
> index 25fcc3c..2fdad63 100644
> --- a/drivers/i2c/busses/i2c-sprd.c
> +++ b/drivers/i2c/busses/i2c-sprd.c
> @@ -86,6 +86,7 @@ struct sprd_i2c {
>   	u32 count;
>   	int irq;
>   	int err;
> +	bool is_suspended;
>   };
>   
>   static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count)
> @@ -283,6 +284,9 @@ static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
>   	struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
>   	int im, ret;
>   
> +	if (i2c_dev->is_suspended)
> +		return -EBUSY;
> +
>   	ret = pm_runtime_get_sync(i2c_dev->dev);
>   	if (ret < 0)
>   		return ret;
> @@ -586,11 +590,23 @@ static int sprd_i2c_remove(struct platform_device *pdev)
>   
>   static int __maybe_unused sprd_i2c_suspend_noirq(struct device *pdev)
>   {
> +	struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev);
> +
> +	i2c_lock_adapter(&i2c_dev->adap);
> +	i2c_dev->is_suspended = true;
> +	i2c_unlock_adapter(&i2c_dev->adap);
> +
>   	return pm_runtime_force_suspend(pdev);
>   }
>   
>   static int __maybe_unused sprd_i2c_resume_noirq(struct device *pdev)
>   {
> +	struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev);
> +
> +	i2c_lock_adapter(&i2c_dev->adap);
> +	i2c_dev->is_suspended = false;
> +	i2c_unlock_adapter(&i2c_dev->adap);
> +
>   	return pm_runtime_force_resume(pdev);
>   }
>   
> 

-- 
regards,
-grygorii

  parent reply	other threads:[~2018-04-09 20:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-09  6:40 Baolin Wang
2018-04-09  6:40 ` [PATCH 2/2] i2c: sprd: Fix the i2c count issue Baolin Wang
2018-04-27 12:14   ` Wolfram Sang
2018-04-09 20:56 ` Grygorii Strashko [this message]
2018-04-10  8:08   ` [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called Baolin Wang
2018-04-27 12:14 ` Wolfram Sang
2018-05-02  3:27   ` Baolin Wang
2018-05-02  5:23     ` Wolfram Sang
2018-05-02  5:48       ` Baolin Wang
2018-05-03 16:26         ` Grygorii Strashko
2018-05-04 12:24           ` I2C PM overhaul needed? (Re: [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called) Wolfram Sang
2018-05-05  1:54             ` Mark Brown
2018-05-05  8:32               ` Wolfram Sang
2018-05-09  8:18                 ` Mark Brown
2018-05-07 17:48             ` Grygorii Strashko
2018-05-08 16:32               ` Wolfram Sang
2018-05-08 18:31                 ` Peter Rosin
2018-05-11 15:14                 ` Grygorii Strashko

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