u-boot fix to charge empty battery

[Werner Almesberger]

Andy Green wrote:
> BVMCTL is set to 2.8V... this "cut off" thing that Werner mentions is a
> pathological case

Yup. Given that one shouldn't have to spend time in wait_for_power
very often (i.e., even if you run down your battery a lot, then you'll
probably also make sure that you have a better power source than just
100mA), the general design principle there was more "survive the day"
than "seize the day".

> The idea in Qi is to defer anything fancy like the looping and flashing
> and whatever until Linux is up, we just try to boot Linux with low power
> (backlight off) and take care of it in there once rather than going on a
> mission to really recreate Linux in U-Boot.

By the way, do we know if we really stay in the 100mA envelope until
the kernel can raise the current limit ?

- Werner