From: Pavel Machek <pavel@ucw.cz>
To: Marcel Holtmann <marcel@holtmann.org>
Cc: David Lechner <david@lechnology.com>,
linux-leds@vger.kernel.org, Richard Purdie <rpurdie@rpsys.net>,
Jacek Anaszewski <j.anaszewski@samsung.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Joel Becker <jlbec@evilplan.org>
Subject: Re: [RFC] User-defined leds
Date: Fri, 5 Aug 2016 21:51:31 +0200 [thread overview]
Message-ID: <20160805195130.GA26694@amd> (raw)
In-Reply-To: <DB74DD94-7737-4F06-BD35-D698A65E30AD@holtmann.org>
Hi!
> > short version: I have a use case for leds where I want to be able to use the triggers in the leds subsystem without having a physical hardware led.
> >
> > long version: I am working on a program to make one embedded system (http://fatcatlab.com/product/evb/) compatible with another (http://mindstorms.lego.com). One has physical red/green LEDs, that use the gpio leds driver to control them. The other system does not have physical leds. However, it does have a color screen. So, my idea is
> > to create virtual LEDs on the screen that emulate the physical LEDs on the other device.
> >
> > I would like to make a userspace program that works the same on both devices. If the leds were simple on-off, then it would of course be simpler to make the virtual leds completely in userspace. However, we are currently using other triggers (disk activity/heatbeat/etc.) with the leds. I would like for the virtual LEDs to be able to use these triggers as well.
>
> this is funny since I have just written a ledsim.c using debugfs to emulate a LED and read out its state via a simple cat command. I found that useful for testing triggers in the Bluetooth subsystem and see if they behave correctly without bothering to run this on real hardware.
>
Could the device tree be used to bind LED driver to otherwise unused
gpio?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2016-08-05 19:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-25 18:36 [RFC] User-defined leds David Lechner
2016-07-25 18:45 ` Marcel Holtmann
2016-07-26 7:38 ` Jacek Anaszewski
2016-08-05 19:51 ` Pavel Machek [this message]
2016-08-05 19:54 ` David Lechner
2016-08-05 19:58 ` Pavel Machek
2016-07-26 7:38 ` Jacek Anaszewski
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