Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758801AbcC3I6k (ORCPT ); Wed, 30 Mar 2016 04:58:40 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:14177 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753391AbcC3I6h (ORCPT ); Wed, 30 Mar 2016 04:58:37 -0400 Message-ID: <1459328310.29450.24.camel@mtksdaap41> Subject: Re: [PATCH] sbs-battery: fix power status when battery is dry From: YH Huang To: Rhyland Klein CC: Daniel Kurtz , , "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" Date: Wed, 30 Mar 2016 16:58:30 +0800 In-Reply-To: <56FA99D0.1010004@nvidia.com> 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6325 Lines: 136 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 status. > >>>>>>>> If BATTERY_DISCHARGING is set, the power status is not charging. > >>>>>>>> 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(struct i2c_client *client, > >>>>>>>> > >>>>>>>> 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; > >>>>>>>> - else > >>>>>>>> + else if (ret & BATTERY_DISCHARGING) { > >>>>>>>> + if (ret & BATTERY_FULL_DISCHARGED) > >>>>>>>> + val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING; > >>>>>>>> + else > >>>>>>>> + val->intval = POWER_SUPPLY_STATUS_DISCHARGING; > >>>>>>>> + } else > >>>>>>> > >>>>>>> > >>>>>>> I think (BATTERY_DISCHARGING && BATTERY_FULL_DISCHARGED) is still > >>>>>>> POWER_SUPPLY_STATUS_DISCHARGING. > >>>>>>> So, let's just report what the battery says and do: > >>>>>>> > >>>>>>> else if (ret & BATTERY_DISCHARGING) > >>>>>>> val->intval = POWER_SUPPLY_STATUS_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 expect to > >>>>> only see NOT_CHARGING if completely discharged *and* not discharging. > >>>> > >>>> 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 > >>>> ‘TERMINATE_DISCHARGE_ALARM’ as an early or first level warning of end of > >>>> battery charge." > >>>> It looks like the FULLY_DISCHARGED status is used to announce the > >>>> warning of battery charge and it is still discharging if there is no one > >>>> takes care of it. > >> > >> > >> The only difference I see in the patch above is that in the case where > >> DISCHARGING isn't set, it won't check FULL_DISCHARGE. Nothing seems to > >> be changed in the case where FULL_DISCHARGE & DISCHARGING are set. > > > > 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? > > > > 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: > > capacity (in the course of running from fully_charged to dry to > recharging...) > > full: FULLY_CHARGED > > high->low: DISCHARGING > ~0%: (DISCHARGING & FULLY_DISCHARGED) > > ->~20%: FULLY_DISCHARGED > >~20%: = charging > > From this understanding, it seems like we can't expect FULLY_DISCHARGED > 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. > > I think this patch would be fine if we wanted to cover that case, though > if we do merge this, we should probably flush out the patch description > 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 turn > 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 => POWER_SUPPLY_STATUS_FULL high->low: BATTERY_DISCHARGING => POWER_SUPPLY_STATUS_DISCHARGING ~0%: DISCHARGING & FULLY_DISCHARGED => POWER_SUPPLY_STATUS_NOT_CHARGING 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?