linux-kernel - Re: [PATCH 3/4] power: supply: mm8013: implement POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR

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Date: Mon, 12 Feb 2024 14:22:04 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Thomas Weißschuh <linux@...ssschuh.net>,
 Hans de Goede <hdegoede@...hat.com>
Cc: Sebastian Reichel <sre@...nel.org>, Konrad Dybcio
 <konradybcio@...nel.org>, linux-pm@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH 3/4] power: supply: mm8013: implement
 POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR_AVAILABLE

On 5.02.2024 12:21, Thomas Weißschuh wrote:
> On 2024-02-05 11:00:01+0100, Hans de Goede wrote:
>> Hi,
>>
>> On 2/4/24 18:26, Thomas Weißschuh wrote:
>>> The sysfs is documented to report both the current and all available
>>> behaviours. For this POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR_AVAILABLE needs
>>> to be implemented.
>>>
>>> Note that this changes the format of the sysfs file
>>> (to the documented format):
>>>
>>> Before: "auto"
>>> After:  "[auto] inhibit-charge"
>>>
>>> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
>>
>> Changing userspace API like this is never ideal, but given how
>> new the mm8013 driver is and that this brings things inline
>> with the docs I think that this should be fine:
> 
> I agree that it's unfortunate.
> 
> However looking at the datasheet [0] it seems to me the driver is
> not correctly using the API.
> 
> Page 23 documents the flag CHG_INH as follows:
> 
>   CHG_INH : Charge Inhibit      When the current is more than or equal to charge
>                                 threshold current,
>                                 charge inhibit temperature (upper/lower limit) ：1
>                                 charge permission temperature or the current is
>                                 less than charge threshold current ：0
> 
> This is only diagnostic information and not a control-knob, which the API
> was meant for.
> So POWER_SUPPLY_STATUS_NOT_CHARGING seems like the better match.

Oh, that's definitely something I glossed over, thanks for taking a look!

I'll send a patch untangling this shortly.

Konrad

> 
>> [..]
> 
> Thomas
> 
> 
> [0] https://product.minebeamitsumi.com/en/product/category/ics/battery/fuel_gauge/parts/download/__icsFiles/afieldfile/2023/07/12/1_download_01_12.pdf