>-------- 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. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
