On Sat, Mar 7, 2015 at 12:56 AM, Pali Roh?r [off-list ref] wrote:

On Friday 06 March 2015 23:40:34 Pavel Machek wrote:

quoted

On Sat 2015-03-07 00:12:07, Grazvydas Ignotas wrote:

quoted

On Fri, Mar 6, 2015 at 11:57 PM, Pali Roh?r
[off-list ref] wrote:

quoted

On Friday 06 March 2015 22:24:17 Pavel Machek wrote:

quoted

Hi!

According to n900 dts, twl4030-bci (aka charger) should
be included.

AFAIK it is not present on n900...

Right, it uses twl5030 variant without the charger, charging
on n900 is provided by separate chip and for a good reason
as twl's charger is not that good. Forcing the driver to
load just ends up with it accessing non-existent registers
over i2c.

Ok, but:

1) Why is the twl4030-bci enabled in n900's dts, then

maybe it is bug in n900 dts...

Grazvydas, is there some runtime check if twl4030/twl5030 chip
has charger or not? or do we need to explicitly disable device
twl4030-bci in DT?

Actually from looking at the schematics, it looks like the charger
pins are still there but all connected to ground. So it probably has
the charger after all, it's just not connected or used.

I'm not aware or any registers for direct detection, and indirect
detection is difficult because BCI mostly disables itself when no
charger is connected and most registers read as 0 or have old values
from last charging session (which will never happen on n900).

There is IDCODE register on twl4030 itself, but it's documented as not
meaningful when accessed over i2c (when is it meaningful then??).

drivers/mfd/twl-core.c has a i2c_device_id table of various twl4030
variants, some of which have no charger. N900 has GAIA/twl5030, which
differs from twl4030 only by vaux2 regulator according to that file.
N900's old board files specify 5030, but .dts does not.


Gra?vydas