Re: libbattery was Re: [RFC PATCH 5/5] power: generic-adc-battery: Add capacity handling

From: H. Nikolaus Schaller
Date: Wed Oct 18 2017 - 11:53:07 EST



> Am 18.10.2017 um 15:56 schrieb Pavel Machek <pavel@xxxxxx>:
>
> On Wed 2017-10-18 06:22:04, Tony Lindgren wrote:
>> * H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> [171018 05:49]:
>>>> Am 18.10.2017 um 14:28 schrieb Pavel Machek <pavel@xxxxxx>:
>>>>
>>>> So I started something, it is at.
>>>>
>>>> https://github.com/pavelmachek/libbattery
>>>>
>>>> My battery on n900 is currently uncalibrated (and charging), still it
>>>> gets some kind of estimation:
>>>>
>>>> Battery -1 %
>>>> Seconds -1
>>>> State 1
>>>> Voltage 3.88 V
>>>> Battery 63 %
>>>>
>>>> Of course, there's a lot more work to be done.
>>>
>>> Nice start but not a solution to our problem.
>>>
>>> Our problem is that people simply expect that for example https://packages.debian.org/wheezy/xfce/xfce4-battery-plugin
>>> displays the battery percentage.
>>
>> I think we could make things compatible with various battery apps by
>> having libbattery write back the capacity percentage and time remaining
>> to the kernel driver via sysfs or a dev entry. Then the kernel interface
>> can just display the data to whatever apps.
>
> Hmm. This could be as simple as providing symlink from
> /sys/class/power/userland-battery to some place writable by
> userspace...

Well, please implement arbitrary symlinks in /sysfs...

root@letux:~# ln -sf /tmp/somewhere /sys/class/power_supply/fake-battery
ln: failed to create symbolic link '/sys/class/power_supply/fake-battery': Operation not permitted
root@letux:~#

And you need to run a daemon so that the data is available
somewhere.

BR and thanks,
Nikolaus

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