Motorola Droid 4 progress, power consumption

* Pavel Machek [off-list ref] [180503 09:08]:

I'd like current_avg more, but if I cat it manually, it changes on
order of seconds, and quite significantly... which suggest shorter
polling interval would be needed.

user at devuan:/sys/class/power_supply/battery$ date; cat current_now
current_avg
Thu May  3 09:33:05 CEST 2018
-71000
-218408
user at devuan:/sys/class/power_supply/battery$ date; cat current_now
current_avg
Thu May  3 09:33:06 CEST 2018
-61000
-200238
user at devuan:/sys/class/power_supply/battery$ date; cat current_now
current_avg
Thu May  3 09:33:06 CEST 2018
-51000
-209879
user at devuan:/sys/class/power_supply/battery$ date; cat current_now
current_avg
Thu May  3 09:33:07 CEST 2018
-56000
-72308
user at devuan:/sys/class/power_supply/battery$ date; cat current_now
current_avg
Thu May  3 09:33:08 CEST 2018
-37000
-211362

I recall it just being calculated based on the time between
the reads. Hard to say what it does, -ENODOCS.. Maybe the mc13783
PMIC docs have something similar.

quoted

Hmm oh and the POWER_SUPPLY_CHARGE_COUNTER value should be monitored
by your libbattery and it's low value and high value should be saved
to a file. Low should be saved when we get the battery low interrupt
and battery state changes to POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL.
High value should be saved on POWER_SUPPLY_CAPACITY_LEVEL_FULL.

Then when you know the high value and low value, you can calculate
the remaining capacity based on the current value and
POWER_SUPPLY_POWER_AVG.

I'll look into that... but probably will do experiments with python,
first.

Sure. The reason why I think we should not do it in the kernel in
addition to the earlier reasoning is that we don't have a place
to store the min and max values across reboot. I think there's
some flash on the battery over 1w bus, but it probably just
contains battery serial number or something and is not intended
for writing much to it. I guess the min and max values should be
really keyd based on this battery id in case the battery gets
changed.

Regards,

Tony