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Date:   Sun, 15 Jul 2018 00:39:07 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc:     Baolin Wang <baolin.wang@linaro.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        Linux LED Subsystem <linux-leds@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] leds: core: Introduce generic pattern interface
Message-ID: <20180714223907.GB2776@amd>
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On Sun 2018-07-15 00:29:25, Pavel Machek wrote:
> On Sun 2018-07-15 00:02:57, Jacek Anaszewski wrote:
> > Hi Pavel,
> >=20
> > On 07/14/2018 11:20 PM, Pavel Machek wrote:
> > >Hi!
> > >
> > >>>It also drew my attention to the issue of desired pattern sysfs
> > >>>interface semantics on uninitialized pattern. In your implementation
> > >>>user seems to be unable to determine if the pattern is activated
> > >>>or not. We should define the semantics for this use case and
> > >>>describe it in the documentation. Possibly pattern could
> > >>>return alone new line character then.
> > >
> > >Let me take a step back: we have triggers.. like LED blinking.
> > >
> > >How is that going to interact with patterns? We probably want the
> > >patterns to be ignored in that case...?
> > >
> > >Which suggest to me that we should treat patterns as a trigger. I
> > >believe we do something similar with blinking already.
> > >
> > >Then it is easy to determine if pattern is active, and pattern
> > >vs. trigger issue is solved automatically.
> >=20
> > I'm all for it. I proposed this approach during the previous
> > discussions related to possible pattern interface implementations,
> > but you seemed not to be so enthusiastic in [0].
> >=20
> > [0] https://lkml.org/lkml/2017/4/7/350
>=20
> Hmm. Reading my own email now, I can't decipher it.
>=20
> I believe I meant "changing patterns from kernel in response to events
> is probably overkill"... or something like that.

Anyway -- to clean up the confusion -- I'd like to see

echo pattern > trigger
echo "1 2 3 4 5 6 7 8" > somewhere

to activate pattern, and

echo none > trigger

to stop it.

Best regards,
								Pavel

--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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