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From: "Dr. H. Nikolaus Schaller" <email@example.com>
To: Pavel Machek <firstname.lastname@example.org>
Cc: Tony Lindgren <email@example.com>,
Marek Belisko <firstname.lastname@example.org>,
Benoit Cousson <email@example.com>,
Sebastian Reichel <firstname.lastname@example.org>,
Dmitry Eremin-Solenikov <email@example.com>,
David Woodhouse <firstname.lastname@example.org>,
Rob Herring <email@example.com>, Pawel Moll <firstname.lastname@example.org>,
Mark Rutland <email@example.com>,
Ian Campbell <firstname.lastname@example.org>,
Kumar Gala <email@example.com>,
firstname.lastname@example.org, LKML <email@example.com>,
Subject: Re: [PATCH v4 3/6] Documentation: DT: Document twl4030-madc-battery bindings
Date: Wed, 1 Apr 2015 10:18:05 +0200 [thread overview]
Message-ID: <BC5A7447-CAD7-4CCE-8F08-8CEFBB5C6905@goldelico.com> (raw)
Am 31.03.2015 um 09:26 schrieb Pavel Machek <firstname.lastname@example.org>:
>>>>> + io-channels = <&twl_madc 1>,
>>>>> + <&twl_madc 10>,
>>>>> + <&twl_madc 12>;
>>>>> + io-channel-names = "temp",
>>>>> + "ichg",
>>>>> + "vbat";
>>>>> + };
>>>> Rather than just making platform_data into device tree properties..
>>>> Can't you hide the these custom properties behind the compatible flag?
>>>> You can initialize that data in the driver based on the compatible
>>>> flag and the match data.
>>>> This makes sense if you can group things to similar configurations.
>>> Maybe I have not completely understood your proposal.
>>> Do you mean to go back to have big parameter tables for each device/battery
>>> combination in the driver code and the compatible flag (e.g. compatible = “board17”)
>>> chooses the right data set for the charging map and channels?
>> If you can somehow group them, then yes. Not for every board if there
>> are many of them naturally.
>>> I thought this is what the DT was introduced for - to have the same driver
>>> code but adapt to different boards depending on hardware variations.
>> Yeah but you also need to consider the issues related to introducing
>> new device tree properties. The device tree properties introduced
>> should be generic where possible.
>>> And batteries have very different characteristics and vary between devices…
>> Right. Maybe that has been already agreed on to use capacity-uah for
>> batteries in general? In that case I have not problem with that as
>> it's a generic property :)
>>> The charging maps are depending on the battery type connected to the twl4030
>>> and which madc channel is which value is also a little hardware dependent
>>> (although the twl4030 doesn’t give much choice).
>> Just to consider alternatives before introducing driver specific
>> property for the maps.. Maybe here you could have few different type
>> of maps and select something safe by default? Of course it could be this
>> is higly board specific, I think some devices may be able to run below
>> 3.3V for example..
> As I explained in some other mail, those tables should not be
> neccessary at all. They can be computed from li-ion characteristics
> and internal resistance, and assumed current during charge and
I already explained that we do not know the charging and discharging
current well enough for such a calculation.
And I explained that the “internal resistance” is a system (battery + cables +
connectors + other circuits) parameter that is not easy to derive or measure
and type into the .dts source code.
At least I have no idea how I should find it out for my boards. While I can
easily determine the curves (and we already have them for the platform_data
Please propose your own code doing that so that we can test if it is
> Running below 3.3V.. not really. At that point, the battery is really
> _empty_, and voltage is going down really really fast.
It is the diffference between 2% and 0% where a fuel indication might
be most important…
> Plus, you are damaging the battery at that point.
The power controller will shut down - but the driver should report
reasonable (but IMHO not necessarily perfect) values until the last
next prev parent reply other threads:[~2015-04-01 8:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-10 21:27 [PATCH v4 0/6] Convert twl4030_madc_battery to IIO consumer and add DT aupport Marek Belisko
2015-03-10 21:27 ` [PATCH v4 1/6] power: twl4030-madc-battery: Convert to iio consumer Marek Belisko
2015-04-06 17:39 ` Sebastian Reichel
2015-03-10 21:27 ` [PATCH v4 2/6] power: twl4030_madc_battery: Add device tree support Marek Belisko
2015-03-10 21:27 ` [PATCH v4 3/6] Documentation: DT: Document twl4030-madc-battery bindings Marek Belisko
2015-03-11 15:24 ` Tony Lindgren
2015-03-11 16:16 ` Dr. H. Nikolaus Schaller
2015-03-11 16:44 ` Tony Lindgren
2015-03-11 17:13 ` Dr. H. Nikolaus Schaller
2015-03-11 17:43 ` Tony Lindgren
2015-03-11 19:36 ` Sebastian Reichel
2015-03-11 19:37 ` Tony Lindgren
2015-03-31 7:26 ` Pavel Machek
2015-04-01 8:18 ` Dr. H. Nikolaus Schaller [this message]
2015-04-01 20:16 ` Pavel Machek
2015-04-01 20:39 ` Dr. H. Nikolaus Schaller
2015-04-04 8:16 ` Pavel Machek
2015-04-04 9:46 ` Dr. H. Nikolaus Schaller
2015-04-01 16:30 ` Rob Herring
2015-04-01 16:46 ` Dr. H. Nikolaus Schaller
2015-03-10 21:27 ` [PATCH v4 4/6] ARM: dts: omap3-gta04: Add battery support Marek Belisko
2015-03-16 20:53 ` Tony Lindgren
2015-03-16 21:04 ` Tony Lindgren
2015-03-10 21:27 ` [PATCH v4 5/6] power: twl4030_madc_battery: Add of_twl4030_madc_match to MODULE_DEVICE_TABLE Marek Belisko
2015-03-10 21:27 ` [PATCH v4 6/6] power: twl4030_madc_battery: Add missing MODULE_ALIAS Marek Belisko
2015-04-06 17:45 ` Sebastian Reichel
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