Re: [PATCH v5 1/4] leds: core: add generic support for RGB Color LED's

From: Pavel Machek <pavel@ucw.cz>
To: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Heiner Kallweit <hkallweit1@gmail.com>, Greg KH <greg@kroah.com>,
	linux-leds@vger.kernel.org,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
	pali.rohar@gmail.com, sre@kernel.org, khilman@kernel.org,
	aaro.koskinen@iki.fi, ivo.g.dimitrov.75@gmail.com,
	Patrik Bachan <patrikbachan@gmail.com>,
	serge@hallyn.com
Subject: Re: [PATCH v5 1/4] leds: core: add generic support for RGB Color LED's
Date: Fri, 15 Apr 2016 13:53:30 +0200	[thread overview]
Message-ID: <20160415115330.GA18196@amd> (raw)
In-Reply-To: <570CA014.7000709@samsung.com>

Hi!

> >>How about implementing patterns as a specific typer of triggers?
> >>Let's say we have ledtrig-rgb-pattern:
> >
> >Well, we'd need ledtrig-rgb-pattern-1, ledtrig-rgb-pattern-2, ... , as we
> >can have more than one rgb led. But yes.
> 
> Triggers can have many listeners, i.e. led_trigger_event() sets
> brightness on all LED class devices registered on given trigger.
> We could have led_trigger_rgb_event() that would set brightness
> on all groups-of-three LEDs registered on given rgb-trigger.

I do not understand that.

> I agree that ledtrig-rgb-pattern-1, ledtrig-rgb-pattern-2, etc. would
> be also needed to add a capability of setting different colors on
> different LED devices.

Ok.

> >For patterns, I'd suggest array of (r g b time) values.
> >
> >Pattern engines can do stuff like "slowly turn LED from off to red, then switch color to
> >white, then slowly turn it to yellow, then turn it off at once" with defined speeds
> >for "slowly" and option of either linear on non-linear brightness ramping.
> >
> >The last option might be a bit too much, but I believe we should support the rest.
> 
> Yes, that's an interesting idea. It also turns out that trigger based
> patterns could be also used for defining generic patterns for a group
> of monochrome LEDs.

Yes, controlling monochrome LEDs synchronously is another task for
patterns. Actually, N900 uses that to control 6 keyboard backlight
LEDs synchronously... and yes, it would be somehow nice to preserve
this functionality.

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