Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760717AbZLOXbj (ORCPT ); Tue, 15 Dec 2009 18:31:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760700AbZLOXbe (ORCPT ); Tue, 15 Dec 2009 18:31:34 -0500 Received: from ns.penguin.cz ([84.21.108.25]:37694 "EHLO ns.penguin.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755798AbZLOXbb (ORCPT ); Tue, 15 Dec 2009 18:31:31 -0500 Subject: Re: [POWER] battery calibration parameters from sysfs From: Stanislav Brabec To: Aras Vaichas Cc: Bill Gatliff , Pavel Machek , Mark Brown , Linus Walleij , cbou@mail.ru, dwmw2@infradead.org, LKML , linux-embedded@vger.kernel.org, Brian Swetland , rpurdie@rpsys.net, lenz@cs.wisc.edu, Dirk@opfer-online.de, arminlitzel@web.de, Cyril Hrubis , thommycheck@gmail.com, linux-arm-kernel , dbaryshkov@gmail.com, omegamoon@gmail.com, eric.y.miao@gmail.com, zaurus-devel@www.linuxtogo.org In-Reply-To: References: <20091207114825.GA26965@rakim.wolfsonmicro.main> <20091207165628.GA24981@rakim.wolfsonmicro.main> <20091213132413.GB1437@ucw.cz> <20091214121247.GB22388@rakim.wolfsonmicro.main> <20091214212257.GA9213@elf.ucw.cz> <4B26FC52.6060307@billgatliff.com> Content-Type: text/plain; charset="ISO-8859-2" Date: Wed, 16 Dec 2009 00:32:18 +0100 Message-Id: <1260919938.10441.18.camel@utx.utx.cz> Mime-Version: 1.0 X-Mailer: Evolution 2.28.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1332 Lines: 34 Aras Vaichas wrote: > Yes, but in that case you might as well just purchase a coulomb > counter with a built-in accumulator and an I2C/SPI/microwire interface > save yourself some PCB space and cost (maybe) Well, Pavel attempts to implement a "poor man's Coulomb counter" or at least "poor man's Ampere meter" for devices that are not equipped with any of it. - We know the time. - We know the backlight power consumption, it's dependent only on brightness. - We know how much eats the HDD and how long it is on. - We know how much eats the CPU and companion chips (it is not as stable, but it eats less). - We don't know, how much USB host eats, but we know how much USB clients claim to eat. - Well, and we don't know how much eats CF and SD. => We can guess how many Coulombs the device already consumed. If the Coulomb counting would be inaccurate, we can at least correct voltage -> remaining energy table using current power consumption guess. ________________________________________________________________________ Stanislav Brabec http://www.penguin.cz/~utx/zaurus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/