[RFC] shutdown machine when li-ion battery goes below 3V
From: Pavel Machek <hidden>
Date: 2016-10-25 10:56:13
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On Tue 2016-10-25 12:53:20, Pali Roh?r wrote:
On Tuesday 25 October 2016 12:24:35 Pavel Machek wrote:quoted
On Mon 2016-10-24 23:48:47, Pali Roh?r wrote:quoted
On Monday 24 October 2016 23:41:52 Pavel Machek wrote:quoted
On Mon 2016-10-24 14:29:33, Tony Lindgren wrote:quoted
Also, the shutdown voltage can depend on external devices connected. It could be for example 3.3V depending on eMMC on some devices while devices with no eMMC could have it at 3.0V.Actually, I'd like to shutdown at 3.3V or more (like 3.5V), because going below that is pretty mean to the battery. But if I set threshold too high, GSM activity will push it below that for a very short while, and I'll shutdown too soon. Ideas welcome...bq27x00 has EDVF flag which means that battery is empty. Maemo with bq27x00 driver is configured to issue system shutdown when EDVF is set. Maybe kernel should issue emergency shutdown e.g. after minute or two after EDVF flag is set?Thanks for pointer. EDVF seems to be exposed as health. ... but only if battery is calibrated, AFAICT.No, EDVF is available also for uncalibrated battery. There are EDV1 and EDVF flags. Both are set based on battery voltage and some other parameters from bq EEPROM.quoted
if (has_ci_flag && (cache.flags & BQ27000_FLAG_CI)) { dev_info_once(di->dev, "battery is not calibrated! ignoring capacity values\n");Yes, it ignores only capacity values (which needs calibration), not those raw flags which works also without calibration.quoted
... cache.health = -ENODATA;
Take a look at code. Health is not read from hardware unless battery is calibrated. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: Digital signature URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20161025/61eece66/attachment.sig>