Neo Freerunner PMU Status

Andy Green andy at
Fri Feb 8 16:51:53 CET 2008

Hash: SHA1

Somebody in the thread at some point said:
> On Fri, Feb 08, 2008 at 09:53:06AM +0000, Andy Green wrote:
>> Basically the MBC decides to power itself from the nonexistant battery
>> for a period, leading to death on VB_SYS and then everywhere else.  The
>> overall effect is --> "off" partway through boot.  It isn't a matter of
>> increasing VB_SYS cap, it has pulled power for a long period.
> Please make sure somebody pushes this observation up to OM's excellent
> nxp PMU contacts in the netherlands (don't go through the FAE).  Werner
> knows the contacts, Sean too.

Well, after fixing the LOWBAT / init kill thing this behaviour seems to
have gone away, instead with no battery in we get 30s period attempts to
charge a "FULL" battery that then is understood to be a (NO)BAT, but no
death.  That is fine.

> The 'monster' comment was referring to the many different things that
> all happen in one driver.  It was actually put in the pcf50606 driver
> when I originally wrote it.    Now given the nature of the complexity of
> those PMU's, the amount of functionality is not going to get any
> smaller.  I'd probably split parts into separate files if the code is
> getting too long, but that's a pure source code reorganization thing.

I am all for trading off beauty against shipping products.  The
situation is immensely complicated by the pretty much uncontrolled I2C
probing aspect.

> With regard to #ifdef's: They are nice temporary hacks.  If something
> like you've described above is really necessary, then a proper
> abstraction interface via platform_data or maybe a notifier_chain should
> be implemented, breaking the board (Gta02) dependent code out of that
> driver.

It seems the need went away, currently my device acts well with or
without a battery after the LOWBAT / NOBAT patch.  I even put the case
on the thing :-)  So I left the original GTA02 #ifdefs as I found them.

- -Andy
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