From mboxrd@z Thu Jan 1 00:00:00 1970 From: pavel@ucw.cz (Pavel Machek) Date: Sun, 15 Jun 2014 00:26:06 +0200 Subject: [PATCH V2 2/2] power: twl4030_charger: attempt to power off in case of critical events In-Reply-To: References: <1401313610-14252-1-git-send-email-nm@ti.com> <1401313610-14252-3-git-send-email-nm@ti.com> <538F18B6.7070102@ti.com> Message-ID: <20140614222606.GB1389@xo-6d-61-c0.localdomain> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu 2014-06-05 01:30:40, Grazvydas Ignotas wrote: > On Wed, Jun 4, 2014 at 4:01 PM, Nishanth Menon wrote: > > On 06/04/2014 05:04 AM, Grazvydas Ignotas wrote: > >> On Thu, May 29, 2014 at 12:46 AM, Nishanth Menon wrote: > >> often while charging on hot summer day. I'd prefer my pandora to not > >> shutdown in such case, it could just stop charging instead. > > Yeah, We could call > > twl4030_charger_enable_ac(false); > > twl4030_charger_enable_usb(bci, false); > > > > But then, is that sufficient? > > From the TRM: > > 7.5.8 Battery Temperature Out-of-Range Detection > > Battery temperature out-of-range detection detects whether the battery > > temperature is within a specific > > range. Detection is possible for two temperature ranges. When the > > battery temperature is not in the > > 2???50?C range or is in the 3???43?C range, the TBATOR1 and TBATOR2 status > > bits rise and an interrupt is > > generated. > > This MADC monitoring function can be enabled by writing to the > > TBATOR1EN (BCIMFEN2[3]) and > > TBATOR2EN (BCIMFEN2[1]) fields. > > > > Battery pack at high temperature is a risk, no? and it may not be just > > charger that might be causing such a condition. Is'nt it safer to shut > > the device down in such a case? > > I don't know, so far nobody has complained about the battery exploding > and anybody getting hurt, but it would make the device unusable for > people in hot climates. From what I remember the automatic charge is > stopped automatically on this condition, as some people complained > they couldn't charge their device and saw these messages in dmesg. I > guess mainline could choose the safer option and shutdown, no strong > opinion about this. Li-ions have strong casing -- battery will not explode, just will grow a bit. And 50C will probably not make it explode immediately, just shorten its life a lot. If your battery is close enough to CPU (for example), it should be something else that heats it up. I think that shutdown by default is a good idea. If particular hardware triggers this a lot _and_ there are no components (CPU, hdd) heating the battery, you may want to just stop charging... but do it per-machine ... Actually, you probably want to stop charging at 37C or so, to stop triggering this... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html