From mboxrd@z Thu Jan 1 00:00:00 1970 From: YH Huang Subject: Re: [PATCH] sbs-battery: fix power status when battery is dry Date: Wed, 30 Mar 2016 16:58:30 +0800 Message-ID: <1459328310.29450.24.camel@mtksdaap41> References: <1458726794-48298-1-git-send-email-yh.huang@mediatek.com> <1458801832.16645.7.camel@mtksdaap41> <1459132330.16645.14.camel@mtksdaap41> <56F95451.5040607@nvidia.com> <1459216353.16645.20.camel@mtksdaap41> <56FA99D0.1010004@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <56FA99D0.1010004@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Rhyland Klein Cc: Daniel Kurtz , linux-pm@vger.kernel.org, Dmitry Eremin-Solenikov , Sebastian Reichel , "linux-kernel@vger.kernel.org" , "moderated list:ARM/Mediatek SoC support" , Matthias Brugger , David Woodhouse , "linux-arm-kernel@lists.infradead.org" List-Id: linux-mediatek@lists.infradead.org On Tue, 2016-03-29 at 11:05 -0400, Rhyland Klein wrote: > On 3/28/2016 9:52 PM, YH Huang wrote: > > On Mon, 2016-03-28 at 11:57 -0400, Rhyland Klein wrote: > >> On 3/28/2016 6:05 AM, Daniel Kurtz wrote: > >>> +Rhyland Klein who original wrote this code... > >>> > >>> On Mon, Mar 28, 2016 at 10:32 AM, YH Huang wrote: > >>>> > >>>> On Fri, 2016-03-25 at 11:06 +0800, Daniel Kurtz wrote: > >>>>> On Thu, Mar 24, 2016 at 2:43 PM, YH Huang wrote: > >>>>>> > >>>>>> Hi Daniel, > >>>>>> > >>>>>> On Thu, 2016-03-24 at 12:01 +0800, Daniel Kurtz wrote: > >>>>>>> Hi YH, > >>>>>>> > >>>>>>> On Wed, Mar 23, 2016 at 5:53 PM, YH Huang wrote: > >>>>>>>> When the battery is dry and BATTERY_FULL_DISCHARGED is set, > >>>>>>>> we should check BATTERY_DISCHARGING to decide the power stat= us. > >>>>>>>> If BATTERY_DISCHARGING is set, the power status is not charg= ing. > >>>>>>>> Or the power status should be charging. > >>>>>>>> > >>>>>>>> Signed-off-by: YH Huang > >>>>>>>> --- > >>>>>>>> drivers/power/sbs-battery.c | 22 ++++++++++++---------- > >>>>>>>> 1 file changed, 12 insertions(+), 10 deletions(-) > >>>>>>>> > >>>>>>>> diff --git a/drivers/power/sbs-battery.c b/drivers/power/sbs= -battery.c > >>>>>>>> index d6226d6..d86db0e 100644 > >>>>>>>> --- a/drivers/power/sbs-battery.c > >>>>>>>> +++ b/drivers/power/sbs-battery.c > >>>>>>>> @@ -382,11 +382,12 @@ static int sbs_get_battery_property(st= ruct i2c_client *client, > >>>>>>>> > >>>>>>>> if (ret & BATTERY_FULL_CHARGED) > >>>>>>>> val->intval =3D POWER_SUPPLY_STATUS_= =46ULL; > >>>>>>>> - else if (ret & BATTERY_FULL_DISCHARGED) > >>>>>>>> - val->intval =3D POWER_SUPPLY_STATUS_= NOT_CHARGING; > >>>>>>>> - else if (ret & BATTERY_DISCHARGING) > >>>>>>>> - val->intval =3D POWER_SUPPLY_STATUS_= DISCHARGING; > >>>>>>>> - else > >>>>>>>> + else if (ret & BATTERY_DISCHARGING) { > >>>>>>>> + if (ret & BATTERY_FULL_DISCHARGED) > >>>>>>>> + val->intval =3D POWER_SUPPLY= _STATUS_NOT_CHARGING; > >>>>>>>> + else > >>>>>>>> + val->intval =3D POWER_SUPPLY= _STATUS_DISCHARGING; > >>>>>>>> + } else > >>>>>>> > >>>>>>> > >>>>>>> I think (BATTERY_DISCHARGING && BATTERY_FULL_DISCHARGED) is s= till > >>>>>>> POWER_SUPPLY_STATUS_DISCHARGING. > >>>>>>> So, let's just report what the battery says and do: > >>>>>>> > >>>>>>> else if (ret & BATTERY_DISCHARGING) > >>>>>>> val->intval =3D POWER_SUPPLY_S= TATUS_DISCHARGING; > >>>>>>> > >>>>>> So we just ignore the special situation (BATTERY_DISCHARGING &= & > >>>>>> BATTERY_FULL_DISCHARGED). > >>>>>> Isn't POWER_SUPPLY_STATUS_NOT_CHARGING a useful information? > >>>>> > >>>>> The battery is discharging. The fact that it is also reporting= that > >>>>> it is already "discharged" just seems premature. I would expe= ct to > >>>>> only see NOT_CHARGING if completely discharged *and* not discha= rging. > >>>> > >>>> I check the "Smart Battery Data Specification Revision 1.1". > >>>> And there are some words about FULLY_DISCHARGED. > >>>> "Discharge should be stopped soon." > >>>> "This status bit may be set prior to the > >>>> =E2=80=98TERMINATE_DISCHARGE_ALARM=E2=80=99 as an early or first= level warning of end of > >>>> battery charge." > >>>> It looks like the FULLY_DISCHARGED status is used to announce th= e > >>>> warning of battery charge and it is still discharging if there i= s no one > >>>> takes care of it. > >> > >> > >> The only difference I see in the patch above is that in the case w= here > >> DISCHARGING isn't set, it won't check FULL_DISCHARGE. Nothing seem= s to > >> be changed in the case where FULL_DISCHARGE & DISCHARGING are set. > >=20 > > If battery is dry(FULLY_DISCHARGED) and is charging(No > > BATTERY_DISCHARGING) by AC at the same time, > > I think it is better to mark as POWER_SUPPLY_STATUS_CHARGING. > > Is this right? > > >=20 > Hmm. I can see where you patch would address that situation. From the > spec, it looks like its expected that the flags should look something > like this: >=20 > capacity (in the course of running from fully_charged to dry to > recharging...) >=20 > full: FULLY_CHARGED > > high->low: DISCHARGING > ~0%: (DISCHARGING & FULLY_DISCHARGED) > > ->~20%: FULLY_DISCHARGED > >~20%: =3D charging >=20 > From this understanding, it seems like we can't expect FULLY_DISCHARG= ED > to ever be the only flag, nor can we expect it to go away when the > system is initially plugged in. In light of this, I can see why your > patch is preferable to the existing code, as the existing code could > imply that the system is either still near 0% when it is in fact > charging. Of course, ideally the status returned would be "LOW BUT > CHARGING" but I can see how CHARGING seems like a better option. >=20 > I think this patch would be fine if we wanted to cover that case, tho= ugh > if we do merge this, we should probably flush out the patch descripti= on > better to clarify why we have to treat FULLY_DISCHARGED as only > applicable while DISCHARGING. This, IMHO, isn't because the > FULLY_DISCHARGED flag comes on early, but rather because it doesn't t= urn > off until ~20%. If I revise the description in this way(using your clear explanation): -----------------------------------------------------------------------= - The battery capacity changing course is like this: full: BATTERY_FULLY_CHARGED =3D> POWER_SUPPLY_STATUS_FULL high->low: BATTERY_DISCHARGING =3D> POWER_SUPPLY_STATUS_DISCHARGING ~0%: DISCHARGING & FULLY_DISCHARGED =3D> POWER_SUPPLY_STATUS_NOT_CHARGI= NG 0%~20%: FULLY_DISCHARGED =3D> POWER_SUPPLY_STATUS_CHARGING 20%~: No flag =3D> POWER_SUPPLY_STATUS_CHARGING =46or 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?