[U-Boot] i.MX28 AUTO_RESTART, watchdog, battery and poweroff

Marek Vasut marex at denx.de
Wed Jul 24 13:40:00 CEST 2013


Dear Hector Palacios,

> Greetings,
> 
> I'm not sure I understand the function mxs_power_clear_auto_restart() in
> spl_power_init.c

We're on the same board there. According to FSL, this is needed on some versions 
of MX28 (translation from the techsupp language: we have no idea where this code 
came from nor what it does, so we will tell you it's important and you shouldn't 
touch it).

I believe the powercode will need a revision and I'll likely get to it once I'm 
done with my current hacking.

> The name of the function seems to indicate that its purpose is to *clear*
> the AUTO_RESTART bit, but it is actually setting it:
> 
> 	setbits_le32(&rtc_regs->hw_rtc_persistent0,
> 			RTC_PERSISTENT0_AUTO_RESTART);
> 
> I believe though, that setting this bit is OK because it guarantees that
> the target can be reset from a reset button or a watchdog reset even when
> powered from the battery.
> 
> Am I missing something? Otherwise I think this function should be renamed
> to mxs_power_set_auto_restart().

I'd ack the rename. Fabio?

Best regards,
Marek Vasut


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