Opps...with ELDK-2.1.0 (ppc_4xx)

[Eugene Surovegin]

At 10:18 AM 4/23/2003, Montgomery, Tim wrote:

>[Wolfgang]
> > >
> > >This means you have a RTC on the I2C bus, right? Same here. It  works
> > >fine on all baords except those with a I2C based RTC. Which is why we
> > >detected the problem so late.
> >
>
>[Eugene]
> > It looks like a bug in m41t00_set_rtc_time.
> >
> > Generic I2C layer is very high-level subsystem and can not be
> > used from the interrupt context.
> >
>
>If the i2c layer cannot be used in the (e.g. timer) interrupt context,
>wouldn't that preclude the use of the i2c layer to provide support (i.e.
>clock updates) to an i2c-based rtc?

Unfortunately, it looks so

>Any suggestions on how to work around this?

We can start kernel thread and call i2c from it (or maybe use one which is
already available in the kernel?) .
<foo>_set_rtc_time will notify this thread when it needs to update RTC from
interrupt.

If you worry about accuracy, we may also remember "jiffies" at the time of
<foo>_set_rtc_time and adjust time accordingly when calling i2c (but I
doubt it's worth it).

Eugene


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