From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [POWER] battery calibration parameters from sysfs Date: Sun, 13 Dec 2009 14:19:22 +0100 Message-ID: <20091213131921.GA1437@ucw.cz> References: <20091204104930.GA28625@sirena.org.uk> <20091207114825.GA26965@rakim.wolfsonmicro.main> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Linus Walleij Cc: Mark Brown , cbou@mail.ru, dwmw2@infradead.org, LKML , linux-embedded@vger.kernel.org > One of the things we're facing is Android, which has > its userspace in plain Java JNI at the end of this link: > http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=s > ervices/jni/com_android_server_BatteryService.cpp;h=8e7cadc6b680fc420d34 > 1faa094c71922946fdab;hb=HEAD > > If you browse down to line 275 you can see it parse the sysfs > attribute "capacity", then this propagates up to the battery > status indicator on *all* Android phones out there. So if > you want to run Android unmodified, this is what you need to > provide. They are effectively using the power sysfs as > their hardware abstraction layer in this case. > > Note: I'm not claiming that Android is doing it right or that > we can't modify this code or so, it's just that this is the way > a few million Android devices out there are actually doing it. Users can't modify them, so they don't count... ...but then there are all the systems that rely on /proc/apm emulation, like openembedded popular on sharp zaurus... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html