From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757362Ab3KYScv (ORCPT ); Mon, 25 Nov 2013 13:32:51 -0500 Received: from smtp-out.abv.bg ([194.153.145.99]:59220 "EHLO smtp-out.abv.bg" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757318Ab3KYScs (ORCPT ); Mon, 25 Nov 2013 13:32:48 -0500 DomainKey-Signature: a=rsa-sha1; s=smtp-out; d=abv.bg; c=simple; q=dns; b=Z9WNiYvWjFFOukWAoi9h0C1kvBEjU4RNfCv1eXZCsOf6tokBJqd0yidsta7OR8rwB j4VLPDyQUuyqsJyznLC0WtdK54LsbIQYHU5+RgrP+fWFoCaQq6z/25UTslK2a05uQym QF162U4br5sWJCv3dzKeTuyybTzaNUk7kIwXGHA= Date: Mon, 25 Nov 2013 20:32:46 +0200 (EET) From: =?UTF-8?B?0JjQstCw0LnQu9C+INCU0LjQvNC40YLRgNC+0LI=?= To: Sebastian Reichel Cc: pavel@ucw.cz, pali.rohar@gmail.com, anton@enomsg.org, dwmw2@infradead.org, tony@atomide.com, linux@arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, aaro.koskinen@iki.fi Message-ID: <1434978251.31721.1385404366021.JavaMail.apache@mail83.abv.bg> Subject: Re: [PATCH v2 2/3] bq2415x_charger: Use power_supply notifier for automode MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Priority: 3 X-Mailer: AbvMail 1.0 X-Originating-IP: 46.249.74.23 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >-------- Оригинално писмо -------- >От: Sebastian Reichel >Относно: Re: [PATCH v2 2/3] bq2415x_charger: Use power_supply notifier for automode >До: Ивайло Димитров >Изпратено на: Понеделник, 2013, Ноември 25 19:14:21 EET > > >On Mon, Nov 25, 2013 at 07:01:54PM +0200, Ивайло Димитров wrote: >>> Now.. Imagine phone left in car in charger (on sun). Likely >>> temperature will reach high values, kernel is charging, dsme will >>> reboot the system, but kernel will start charging again, dsme will >>> reboot again, ... >>> >>> And it is not only high temperatures that are problem for li-ion >>> charging; battery should not be fast charged below 5C and should not >>> be charged below 0C. (Again, both are likely to happen if you leave >>> your phone in car). >>> >>> AFAICT, we should simply disable charging below 5C or above 45C. >> >> AFAIK dsme will not restart it, but power it off, so the above >> scenario won't happen. > >Just assume what happens, when dsme does not start (e.g. system boot >hangs). > >If everything is controlled from userspace, charger would not start >(-> safe!). If everything is controlled by the kernel, temperature >safety checks are taken (-> safe!). But in the currently proposed >variant: No safety checks. > >-- Sebastian > > Hmm, you have a point here :) So, AIUI there are 2 options: 1. charger driver polls the battery driver every n (60?) seconds. 2. battery driver sends PSY_EVENT_PROP_CHANGED on every degree up or down In both cases if the temperature is outside of the safe margins, the charging should be stopped. 2 seems more generic to me, but as rx51-battery is missing the functionality to send events on temperature change, I guess 1 will be easier to implement. And I think there should be some method (sysfs entry?, /dev/bqxxx opened?) to tell the charger driver to stop polling the battery driver once (and if) the userspace has started to take care of the battery temperature - makes no sense to duplicate the checks IMO.