Re: Generic battery interface

Vojtech Pavlik
2006-07-27T23:32:09Z

On Fri, Jul 28, 2006 at 12:16:32AM +0200, Pavel Machek wrote:

> /dev/XXX
> + battery layer will need to be invented
> - that layer will need maintainer
> + maintainer ensures this is not a mess, allocates numbers

and figures out which features are identical, which not, etc. This
will actually be a lot easier than with keyboards: The number of
different battery drivers/types is rather limited fortunately.

note: It's absolutely necessary to limit the API to a well usable
SUBSET of a superset of the features of all drivers/devices,
even sacrificing obscure features to keep the API sane. One
example would be the HID Power spec, which simply can't be
supported to full extent by any sane API.

> - does not quite suit zaurus-style batteries, that can _only_ be
> polled. Can be worked-around by polling from kernel (and we
> are often doing that, anyway)

+ and the kernel can change the polling frequency based on power
saving state changes

> + userspace backdoor interface will need to be invented, /dev/uinput style
> - hard to handle obscure features
> (do_not_charge_battery_for_X_minutes), and we'll probably want
> to unify batteries a bit, probably loosing precision.

--
Vojtech Pavlik
Director SuSE Labs