Re: [PATCH v3] power_supply: Add driver for TWL4030/TPS65950 BCI charger

[Arun Murthy]

On Mon, Sep 27, 2010 at 6:38 PM, Grazvydas Ignotas <notasas@xxxxxxxxx> wrote:
> On Mon, Sep 27, 2010 at 3:35 PM, Arun Murthy <arunrmurthy.83@xxxxxxxxx> wrote:
>> On Mon, Sep 27, 2010 at 4:24 PM, Grazvydas Ignotas <notasas@xxxxxxxxx> wrote:
>>> On Mon, Sep 27, 2010 at 10:21 AM, Arun Murthy <arunrmurthy.83@xxxxxxxxx> wrote:
>>> The problem is that BCI is only active while charging, when it is not
>>> charging most (all?) monitoring registers freeze and no monitoring
>>> happens (BCI registers read frozen values from last charge). So I
>>> don't register battery as it has no useful data to report. I heard it
>>> is possible to use MADC to perform monitoring while not charging, so
>>> battery can be added when MADC driver is merged and corresponding code
>>> is written for this driver.
>>>
>> How do I check the battery voltage?
>> I need to check the battery voltage/current/temp and, if I am not
>> wrong these are obtained from MADC.
>> MADC driver has to be added first and then the battery.
>> With being able to read the basic parameter battery voltage, this
>> driver becomes incomplete.
>
> Incomplete driver is better than no driver, don't you think? There are
> some boards like pandora or oswald that have additional battery
> monitoring chips (as twl monitoring is pretty crude anyway), those
> boards would have fully functional charging now. Currently mainline
> kernel is not very useful with them simply because the battery runs
> flat.
I agree, but I feel it would be better to make driver compatible with
all boards(Zoom2, OMAP3430SDP, Chameleon, BeagleBoard etc).
Even support for back-up battery is not supported.
This is just a suggestion to have a full fledged driver for twl4030
Battery Charger Interface as a module. You may discard this if you
have some strong reasons.

>
>> How do I get notified if battery voltage is low and needs charging
>> from user space?
>
> Either additional monitoring chip notifies you (if you are lucky and
> have one), or wait for update of this driver :) There are efforts to
> merge MADC driver [1], but it may take some time.
But using MADC, I can get the battery voltage and by means of
monitoring battery voltage we can get to know low battery
notification.
>
> [1] http://marc.info/?t=128461535700002&r=1&w=2
>
Thanks and Regards,
Arun R Murthy
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