[Gta04-owner] Phoenux drained and resuscitated

[Neil Jerram]

On Sat, 22 Oct 2011 11:58:55 +0200, Dr. H. Nikolaus Schaller wrote:
> Hi Neil,

Hi Nikolaus,

> Yes! Linux initializes the USB charger in one of the earlier steps
> and then the system comes up.
>
> As long as your PC supplies enough current (>500 mA) and you don't
> switch on too many high
> power consumers (WLAN, WWAN), there should be some remainder for
> charging the battery.

Well so far I haven't touched WLAN or WWAN, so I presume they're still 
switched off.  And with the GTA02 it was always said that it could draw 
500mA from a USB connection.

Presumably, then, with the wall charger - which supplies 1000mA - it 
will always be possible to recover from a drained battery?

> Maybe we can improve that by enabling USB charging already in MLO
> i.e. some seconds before (2).
> It is a little tricky since MLO does not have an elaborated I2C
> infrastructure to access the PMU. And
> is quite difficult to debug. So never touch a running system :)

I don't know what the details mean here, but I'm amused by your last 
comment.

> The level where the system starts is 3.2 V. If the voltage stays
> above 3.2 V it keeps running. Then, it should slowly go
> up to 4.2 V (battery full).
>
> What I am not sure about is if the value of current_now is correct.
> It is the same range as I have seen,
> but I suspect some bug in the calculation in the driver.
>
> The capacity is not a valid value - the twl4030 can't read that.

Ah, that's why /sys/.../capacity is not mentioned on the page at 
http://projects.goldelico.com/p/gta04-kernel/page/Power/.

So at the moment, if one wanted to implement a battery monitor GUI 
(which I may do later today), the only sensible thing to display is the 
voltage.

Thanks for your helpful responses as ever,

        Neil