* Pavel Machek <pavel@xxxxxx> [180504 20:22]: > Hi! > > > > user@devuan:/sys/class/power_supply/battery$ date; cat current_now > > > current_avg > > > Thu May 3 09:33:07 CEST 2018 > > > -56000 > > > -72308 > > > user@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. > > Hmm. current_avg is world readable; if it does changes to the > hardware, that's somehow bad. No it just calls cpcap_battery_cc_get_avg_current() that calculates the average from last time it got sampled based on number of samples collected between the two reads. Seems to match what I see on my power supply here. > But I guess I can sample charge_counter every minute or so and get > what I need? Not sure what the max time range is for the PMIC, but yeah I'd assume once a minute is duoable. Maybe compare it to the chart you already have? > > > > 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. > > I agree this should not be done in kernel as it requires persistent > storage. > > Battery is not user-replacable (and this will recalibrate itself on > charge/discharge cycle) so.. I don't think keying is strictly > neccessary for D4. Yeah right, that can be added later on if needed if you just plan accordingly. It's replaceable with a T5 after you peel off the sticker from the corners :) Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
