Re: [PATCH] power_supply: Add driver for TWL4030/TPS65950 BCI charger

[Felipe Balbi <felipe.balbi@nokia.com>]

Hi,

On Thu, Dec 03, 2009 at 11:55:12AM +0100, ext Grazvydas Ignotas wrote:
>TPS65950 is catalog part of TWL4030 and has documentation here:
>http://focus.ti.com/docs/prod/folders/print/tps65950.html#technicaldocuments
>
>It says that it is software's responsibility to detect the device and
>set the right charge mode/current..

yes, the BCI (or bq24xxx) will never be able to know which configuration 
we were enumerated with...

>> yes, that'll work. But how about start charging always with 100mA and if
>> userland sees that we were enumerated it reconfigures charging as necessary.
>> But this would mean that we have the EM daemon started up just after the
>> driver itself is loaded to avoid the problem with 100ms no enumeration. How
>> does that sound ? Do we start making some writeable power_supply sysfs ???
>
>There are also USB chargers that don't enumerate and have D+ and D-
>shorted with a resistor (see "dedicated charger port" in the charging
>spec), how do we support those?

dedicated chargers are simple. You kick the charger detection according 
to USB BC 1.x and if it returns true, you configure high current 
charging. Host/Hub chargers are also simple, after kicking charger 
detection, you enable Data pullups (e.g. SOFTCONN bit in musb's power 
register) and see if the host sends a setup packet...

the complicated part is passing the information of which configuration 
you were enumerated with to the charger chip.

-- 
balbi