[PATCH v3 02/14] mfd: max77686: Allow the max77686 rtc to wakeup the system

[Doug Anderson]

Hi,

On Wed, Jun 25, 2014 at 3:29 AM, Javier Martinez Canillas
<javier.martinez at collabora.co.uk> wrote:
> Yes, the original Chrome OS 3.8 max77xxx also called the irq worker thread to
> ack the interrupt.
>
> So the real problem is that an interrupt occurs before the I2C bus controller is
> resumed and so the interrupt handler is not able to access the registers over I2C.
>
> Doug posted the following patches [0,1] that AFAIU solves the issue by making
> I2C controllers to be resumed in the noirq time to ensure that drivers will be
> able to use the I2C bus to handler their wakeup.

Yup, that's the solution as far as I know.  I know that in ChromeOS we
still have the extra call to the worker thread (despite the controller
waking up early), but that might be related to some other problem?

I was able to successfully suspend/resume multiple times once I woke
the i2c controller up earlier.

If you feel like adding Reviewed-by / Tested-by to my i2c patch then
feel free!  ;)


> In fact, Doug's original patch had this as a part of the commit message:
>
> NOTE: due to wakeup ordering problems this patch alone doesn't work so
> well on exynos5250-snow.  You also need something that brings the i2c
> bus up before the max77686 wakeup runs.
>
> I removed that note since I (probably wrong) thought that he didn't mean it to
> be part of the commit message but just was side information.

I probably would have left that in the patch, but I'm not objecting to
you taking it out.  :)