[ltp] Generic battery interface

[Pavel Machek]

Hi!

(Vojtech and other thinkpad users: look at tp_smapi package; it
includes stuff like "do not charge battery unless it is below 90%",
which should make your battery last few more years).

(I'll still need to test it on x60, sorry).

Anyway, unlike acpi, tp_smapi uses some reasonably-nice
one-value-per-file sysfs interface. I have few objections:

0) it needs to move to /sys/class/battery/tp_smapi or something like
that
 
1) it probably should not include units in the files (hard to parse,
and someone may have great idea to choose different units)

2) some optional method for battery applets to avoid polling would be
nice (OTOH tp_smapi probably does not support notifications, so it is
not its fault)

3) some fields look almost too specialized, but if hardware supports
them, I guess we should export them, too...

...but otherwise it looks very good, certainly better than
alternatives. Perhaps we should make something like this "generic"
battery interface?

Good description is at
http://thinkwiki.org/wiki/Tp_smapi#Installation_from_source , and to
give you a quick example:

# cat /sys/devices/platform/smapi/BAT0/installed
# cat /sys/devices/platform/smapi/BAT0/state       # idle/charging/discharging
# cat /sys/devices/platform/smapi/BAT0/cycle_count 
# cat /sys/devices/platform/smapi/BAT0/current_now # instantaneous  current
# cat /sys/devices/platform/smapi/BAT0/current_avg # last minute average
# cat /sys/devices/platform/smapi/BAT0/power_now   # instantaneous  power
# cat /sys/devices/platform/smapi/BAT0/power_avg   # last minute  average
# cat /sys/devices/platform/smapi/BAT0/last_full_capacity
# cat /sys/devices/platform/smapi/BAT0/remaining_capacity
# cat /sys/devices/platform/smapi/BAT0/design_capacity
# cat /sys/devices/platform/smapi/BAT0/voltage
# cat /sys/devices/platform/smapi/BAT0/design_voltage
# cat /sys/devices/platform/smapi/BAT0/manufacturer
# cat /sys/devices/platform/smapi/BAT0/model
# cat /sys/devices/platform/smapi/BAT0/barcoding
# cat /sys/devices/platform/smapi/BAT0/chemistry
# cat /sys/devices/platform/smapi/BAT0/serial
# cat /sys/devices/platform/smapi/BAT0/manufacture_date
# cat /sys/devices/platform/smapi/BAT0/first_use_date
# cat /sys/devices/platform/smapi/ac_connected

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html