[ltp] Re: Generic battery interface

[Vojtech Pavlik]

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