linux-kernel - Re: [PATCH v2 2/2] power: bq27xxx_battery: add poll interval property query

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Message-ID: <CAKzfze8d_MZJzR1a6rbwVXCWhb30C5GqFamUt2Viw1CzvyaQxw@mail.gmail.com>
Date:   Thu, 3 Nov 2016 22:00:56 -0700
From:   Matt Ranostay <mranostay@...il.com>
To:     Pavel Machek <pavel@....cz>
Cc:     Matt Ranostay <matt@...ostay.consulting>, pali.rohar@...il.com,
        Sebastian Reichel <sre@...nel.org>,
        kernel list <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux OMAP List <linux-omap@...r.kernel.org>,
        Tony Lindgren <tony@...mide.com>, khilman@...nel.org,
        aaro.koskinen@....fi, ivo.g.dimitrov.75@...il.com,
        Patrik Bachan <patrikbachan@...il.com>, serge@...lyn.com,
        Mickuláš Qwertz <abcloriens@...il.com>
Subject: Re: [PATCH v2 2/2] power: bq27xxx_battery: add poll interval property query

On Wed, Nov 2, 2016 at 1:22 AM, Pavel Machek <pavel@....cz> wrote:
> Hi!
>
>> >> >> Better then previous one.
>> >> >>
>> >> >> But my version of bq27xxx_battery.c already contains this:
>> >> >
>> >> > This is for allowing udev rule to set the properties as well.
>> >> > otherwise a kinda crude RUN = " echo value >
>> >> > /sys/module/bq27xxx_battery/parameters/poll_interval" is required.
>> >>
>> >> Any thoughts on this?
>> >
>> > I'd say  echo value >
>> > /sys/module/bq27xxx_battery/parameters/poll_interval .. is quite
>> > adequate solution...?
>> >
>> > Alternatively, convince us that something else is useful for everyone,
>> > and we can do the right thing (poll more often when battery is nearly
>> > empty), automatically...
>>
>> Ok should have had the patchset set it per device, and not use the
>> global poll_interval. Of need to add some logic to see if uses the
>> global poll_interval or it's own setting.
>>
>> There are times where you could have multiple batteries connected to
>> multiple fuel gauges, and want to up the polling interval on certain
>> ones that are discharging at different rates.
>>
>> But of course I'll let you guys let me know if this seems useful at all.
>
> I agree per-device polling would be cleaner.
>

Ok I'll work something up for RFC.

> But unless you have hardware with more than one bq27xxx, I'd avoid the
> work...
>
> Now... its also possible that poll_interval should change itself
> (within kernel) to do the right thing.
>

True but that is state machine territory, but I'll worry about that later...

> Best regards,
>
>                                                                         Pavel
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html