lkml.org 
[lkml]   [2018]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/2] i2c: sprd: Prevent i2c accesses after suspend is called
From
Date


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

\
 
 \ /
  Last update: 2018-04-09 22:57    [W:0.100 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site