Re: [PATCH v2] ARM: OMAP: i2c: fix interrupt flood during resume

[Kalle Jokiniemi <kalle.jokiniemi-4y2FMlU5MS8onNqTyK5kxQ@public.gmane.org>]

ke, 2012-10-10 kello 14:54 +0300, Kalle Jokiniemi kirjoitti:
> ke, 2012-10-10 kello 14:46 +0300, Kalle Jokiniemi kirjoitti:
> > The resume_noirq enables interrupts one-by-one starting from
> > first one. Now if the wake up event for suspend came from i2c
> > device, the i2c bus irq gets enabled before the threaded
> > i2c device irq, causing a flood of i2c bus interrupts as the
> > threaded irq that should clear the event is not enabled yet.
> > 
> > Fixed the issue by adding suspend_late and resume_early
> > functions that keep i2c bus interrupts disabled until
> > resume_noirq has run completely.

Ugh, forgot to update commit message. Version 3 coming shortly...

- Kalle


> > 
> > Issue was detected doing a wake up from autosleep with
> > twl4030 power key on N9. Patch tested on N9.
> 
> I did this now on top of latest linux-omap, should apply also to Jean's
> staging tree. Let me know if something more is needed.
> 
> - Kalle
> 
> > 
> > Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi-4y2FMlU5MS8onNqTyK5kxQ@public.gmane.org>
> > ---
> >  drivers/i2c/busses/i2c-omap.c |   34 ++++++++++++++++++++++++++++++++++
> >  1 files changed, 34 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> > index a0e49f6..991341b 100644
> > --- a/drivers/i2c/busses/i2c-omap.c
> > +++ b/drivers/i2c/busses/i2c-omap.c
> > @@ -1132,6 +1132,36 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev)
> >  }
> >  
> >  #ifdef CONFIG_PM
> > +#ifdef CONFIG_PM_SLEEP
> > +static int omap_i2c_suspend_noirq(struct device *dev)
> > +{
> > +
> > +	struct platform_device *pdev = to_platform_device(dev);
> > +	struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
> > +
> > +	/* Disabling irq here to balance the enable in resume_early */
> > +	disable_irq(_dev->irq);
> > +	return 0;
> > +}
> > +
> > +static int omap_i2c_resume_early(struct device *dev)
> > +{
> > +
> > +	struct platform_device *pdev = to_platform_device(dev);
> > +	struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
> > +
> > +	/*
> > +	 * The noirq_resume enables the interrupts one by one,
> > +	 * this causes a interrupt flood if the SW irq actually reading
> > +	 * event from i2c device is enabled only after i2c bus irq, as the
> > +	 * irq that should clear the event is still disabled. We have to
> > +	 * keep the bus irq disabled until all other irqs have been enabled.
> > +	 */
> > +	enable_irq(_dev->irq);
> > +
> > +	return 0;
> > +}
> > +#endif
> >  #ifdef CONFIG_PM_RUNTIME
> >  static int omap_i2c_runtime_suspend(struct device *dev)
> >  {
> > @@ -1183,6 +1213,10 @@ static int omap_i2c_runtime_resume(struct device *dev)
> >  #endif /* CONFIG_PM_RUNTIME */
> >  
> >  static struct dev_pm_ops omap_i2c_pm_ops = {
> > +#ifdef CONFIG_PM_SLEEP
> > +	.suspend_noirq = omap_i2c_suspend_noirq,
> > +	.resume_early = omap_i2c_resume_early,
> > +#endif
> >  	SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
> >  			   omap_i2c_runtime_resume, NULL)
> >  };
> 
> 
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