Re: [PATCH v3 1/2] leds: core: Introduce generic pattern interface

From: Pavel Machek <pavel@ucw.cz>
To: Baolin Wang <baolin.wang@linaro.org>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	David Lechner <david@lechnology.com>,
	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
Date: Wed, 18 Jul 2018 14:08:36 +0200	[thread overview]
Message-ID: <20180718120836.GB23157@amd> (raw)
In-Reply-To: <CAMz4kuJa=s19q7wQFQT1giUe0AN4hpux4PG2koUcnE7q_x7LCQ@mail.gmail.com>

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On Wed 2018-07-18 19:32:01, Baolin Wang wrote:
> On 18 July 2018 at 15:56, Pavel Machek <pavel@ucw.cz> wrote:
> > Hi!
> >
> >> >>>>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
> >> >>
> >> >>s/somewhere/pattern/
> >> >>
> >> >>pattern trigger should create "pattern" file similarly how ledtrig-timer
> >> >>creates delay_{on|off} files.
> >
> > Yes, that sounds reasonable. v5 still says
> >
> > +               Writing non-empty string to this file will activate the pattern,
> > +               and empty string will disable the pattern.
> >
> > I'd deactivate the pattern by simply writing something else to the
> > trigger file.
> 
> For the case we met in patch 2, it is not related with trigger things.
> We just set some series of tuples including brightness and duration
> (ms) to the hardware to enable the breath mode of the LED, we did not
> trigger anything. So it is weird to write something to trigger file to
> deactive the pattern.

Confused. I thought that "breathing mode" would be handled similar way
to hardware blinking: userland selects pattern trigger, pattern file
appears (similar way to delay_on/delay_off files with blinking), he
configures it, hardware brightness follows the pattern ("breathing
mode"). If pattern is no longer required, echo none > trigger stops
it.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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