From: Pavel Machek <pavel@ucw.cz>
To: "Guido Günther" <agx@sigxcpu.org>
Cc: kernel list <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: Camera LED on Librem 5 was Re: [PATCH] backlight: add led-backlight driver
Date: Sun, 23 Aug 2020 23:22:42 +0200 [thread overview]
Message-ID: <20200823212242.incofjd73vemyazj@duo.ucw.cz> (raw)
In-Reply-To: <20200814172320.GA740513@bogon.m.sigxcpu.org>
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Hi!
> > > > This patch adds a led-backlight driver (led_bl), which is similar to
> > > > pwm_bl except the driver uses a LED class driver to adjust the
> > > > brightness in the HW. Multiple LEDs can be used for a single backlight.
> > >
> > > Tested-by: Guido Günther <agx@sigxcpu.org>
> >
> > Thanks for testing!
> >
> > I noticed blog post about using Librem 5 torch. Unfortunately, it used
> > very strange/non-standard interface, first using LED as a GPIO to
> > enable LED controller, then direct i2c access. That is not acceptable
> > interface for mainline, and it would be better not to advertise such
> > code, as it will likely become broken in future.
>
> I agree, there's a driver for the lm3560 in media/ but how would one
> expose the torch part as a LED? It seems you hit something similar in
>
> https://lkml.org/lkml/2018/5/6/30
(Actually, I might have been wrong in that comment).
> I also couldn't find an in tree driver that registers a flashlight
> as a v4l subdev. Did i miss that?
You should get interface similar to this:
https://wiki.postmarketos.org/wiki/PINE64_PinePhone_(pine64-pinephone)
and the driver to enable that should already be in the mainline:
drivers/leds/leds-sgm3140.c
Best regards and good luck,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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prev parent reply other threads:[~2020-08-23 21:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 19:14 [PATCH] backlight: add led-backlight driver Pavel Machek
2020-02-19 19:45 ` Tony Lindgren
2020-02-19 20:53 ` Pavel Machek
2020-02-19 21:15 ` Tony Lindgren
2020-02-19 23:54 ` Pavel Machek
2020-02-19 23:44 ` Sebastian Reichel
2020-02-20 14:54 ` Tony Lindgren
2020-02-20 7:48 ` Lee Jones
2020-02-20 15:09 ` Tony Lindgren
2020-02-20 8:29 ` Guido Günther
2020-02-20 23:41 ` Camera LED on Librem 5 was " Pavel Machek
2020-08-14 17:23 ` Guido Günther
2020-08-23 21:22 ` Pavel Machek [this message]
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