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

[Grazvydas Ignotas <notasas@gmail.com>]

On Thu, Dec 3, 2009 at 1:03 PM, Felipe Balbi <felipe.balbi@nokia.com> wrote:
> 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.

Ok since it doesn't look like this will resolve soon, what about
adding some DEVICE_ATTR for the time being and requiring userspace to
write charge current here to start actual charging?