linux-kernel - Re: [PATCH] sbs-battery: fix power status when battery is dry

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Message-ID: <1459392151.29450.44.camel@mtksdaap41>
Date:	Thu, 31 Mar 2016 10:42:31 +0800
From:	YH Huang <yh.huang@...iatek.com>
To:	Sebastian Reichel <sre@...nel.org>
CC:	Rhyland Klein <rklein@...dia.com>,
	Daniel Kurtz <djkurtz@...omium.org>,
	<linux-pm@...r.kernel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"moderated list:ARM/Mediatek SoC support" 
	<linux-mediatek@...ts.infradead.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] sbs-battery: fix power status when battery is dry

On Wed, 2016-03-30 at 17:09 +0200, Sebastian Reichel wrote:
> Hi,
> 
> On Wed, Mar 30, 2016 at 04:58:30PM +0800, YH Huang wrote:
> > If I revise the description in this way(using your clear explanation):
> > ------------------------------------------------------------------------
> > The battery capacity changing course is like this:
> > 
> > full: BATTERY_FULLY_CHARGED => POWER_SUPPLY_STATUS_FULL
> > <unplug AC>
> > high->low: BATTERY_DISCHARGING => POWER_SUPPLY_STATUS_DISCHARGING
> > ~0%: DISCHARGING & FULLY_DISCHARGED => POWER_SUPPLY_STATUS_NOT_CHARGING
> > <plug in AC>
> > 0%~20%: FULLY_DISCHARGED => POWER_SUPPLY_STATUS_CHARGING
> > 20%~: No flag => POWER_SUPPLY_STATUS_CHARGING
> > 
> > For now, it is not exactly right to show the status as
> > POWER_SUPPLY_STATUS_NOT_CHARGING when the battery is dry
> > (FULLY_DISCHARGED) and AC is plugged in.
> > Although the battery is in a low level, system works fine with the AC
> > charging.
> > It is better to say that the battery is charging.
> > ------------------------------------------------------------------------
> > 
> > How about this?
> > By the way, should I also revise the title?
> 
> POWER_SUPPLY_STATUS_NOT_CHARGING is used for AC connected, but
> battery not charging (e.g. because battery temperature is out
> of acceptable range). If you are discharging use
> POWER_SUPPLY_STATUS_DISCHARGING.
> 
> You should just ignore the FULLY_DISCHARGED bit in the status
> property. If you don't want to loose the information about fully
> discharged battery add POWER_SUPPLY_PROP_CAPACITY_LEVEL, which maps:
> 
> BATTERY_FULLY_CHARGED => POWER_SUPPLY_CAPACITY_LEVEL_FULL
> FULLY_DISCHARGED => POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL
> otherwise => POWER_SUPPLY_CAPACITY_LEVEL_NORMAL

Oops.
It looks like I misunderstand POWER_SUPPLY_STATUS_NOT_CHARGING.
As Daniel said before, we could just ignore FULLY_DISCHARGED.

So change like the

sbs-battery: fix power status when battery charging near
dry

POWER_SUPPLY_STATUS_NOT_CHARGING is used for AC connected, but
battery not charging (e.g. because battery temperature is out
of acceptable range).

When battery is charging near dry and BATTERY_FULL_DISCHARGED is set,
it is wrong to set as POWER_SUPPLY_STATUS_NOT_CHARGING.
Just use BATTERY_DISCHARGING to decide the power supply status is
discharging or charging.

                if (ret & BATTERY_FULL_CHARGED)
                        val->intval = POWER_SUPPLY_STATUS_FULL;
-               else if (ret & BATTERY_FULL_DISCHARGED)
-                       val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                else if (ret & BATTERY_DISCHARGING)
                        val->intval = POWER_SUPPLY_STATUS_DISCHARGING;


YH Huang