Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754637AbcC1P5J (ORCPT ); Mon, 28 Mar 2016 11:57:09 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:1950 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753738AbcC1P5I convert rfc822-to-8bit (ORCPT ); Mon, 28 Mar 2016 11:57:08 -0400 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Mon, 28 Mar 2016 08:55:23 -0700 Subject: Re: [PATCH] sbs-battery: fix power status when battery is dry To: Daniel Kurtz , YH Huang References: <1458726794-48298-1-git-send-email-yh.huang@mediatek.com> <1458801832.16645.7.camel@mtksdaap41> <1459132330.16645.14.camel@mtksdaap41> CC: Sebastian Reichel , Dmitry Eremin-Solenikov , David Woodhouse , Matthias Brugger , , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "moderated list:ARM/Mediatek SoC support" From: Rhyland Klein Message-ID: <56F95451.5040607@nvidia.com> Date: Mon, 28 Mar 2016 11:57:05 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3910 Lines: 88 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. I think in the case that both flags are set, it makes sense to prioritize the FULL_DISCHARGE, since as quote above actually starts with "FULLY_DISCHARGED bit is set when the Smart Battery determines that it has supplied all the charge it can." I think at the point where both statuses are reported, the fact that it is still DISCHARGING doesn't matter. The code as is handles this in that manner, so I don't see a need to change it. -rhyland -- nvpublic