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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Felipe Balbi <balbi@ti.com>
Cc: Bryan Wu <cooloney@gmail.com>, Richard Purdie <rpurdie@rpsys.net>,
	"linux-leds@vger.kernel.org" <linux-leds@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
	"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>
Subject: Re: "advanced" LED controllers
Date: Wed, 25 Feb 2015 09:25:24 +0100	[thread overview]
Message-ID: <CAMuHMdUUNzFYHzSR3yLCJuz11vuO3Z4yVWVxRQfutGY1KxZLPQ@mail.gmail.com> (raw)
In-Reply-To: <20150219211424.GN13603@saruman.tx.rr.com>

CC linux-gpio, as this looks like the LED equivalent of bulk gpio?

On Thu, Feb 19, 2015 at 10:14 PM, Felipe Balbi <balbi@ti.com> wrote:
> Do we have support for LED controllers which can handle patterns of
> different kinds ? I mean, currently, if we have an LED controller such
> as TPIC2810 [1] which can control 8 different leds and each LED
> corresponds to one bit on register 0x44, we could control leds by just
> "playing" a wave file on the controller and create easy patterns with
> that.
>
> AFAICT, in linux today we would have to register each of the 8 LEDs as a
> different LED and have driver magic to write the proper bits on register
> 0x44, that seems a bit overkill, specially when we want to make
> patterns: instead of writing 0xff we would have to write 0x80, 0x40,
> 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 separately and have the driver cache
> the previous results so we don't end up switching off other LEDs.
>
> IOW, what could be handled with a single write, currently needs 8.
>
> I wonder if there's any work happening to support these slightly more
> inteligent LED engines.
>
> regards
>
> [1] http://www.ti.com/product/tpic2810
>
> ps: tpic2810 is probably the simplest example, lp551, lp5523 and others
> have even more advanced pattern engines which can even handle RGB leds.
>
> Currently the driver loads patterns as if it was a firmware blob and
> registers each of R, G and B components as separate LEDs. Each component
> also has its own brightness controls (something tpic2810 doesn't have,
> it's either on or off).

  parent reply	other threads:[~2015-02-25  8:25 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-19 21:14 Felipe Balbi
2015-02-23 22:34 ` Pavel Machek
2015-02-23 22:58   ` Felipe Balbi
2015-02-25 21:49     ` Pavel Machek
2015-02-25 23:55       ` NeilBrown
2015-02-28 16:18         ` Pavel Machek
2015-02-25  8:25 ` Geert Uytterhoeven [this message]
2015-02-25  9:06   ` Alexandre Courbot
2015-03-02  9:21     ` Pavel Machek
2015-03-03  8:15       ` Alexandre Courbot
2015-03-08 20:57         ` RGB LED control (was Re: "advanced" LED controllers) Pavel Machek
2015-03-09  8:08           ` Geert Uytterhoeven
2015-03-09  9:08             ` Pavel Machek
2015-03-09 11:50             ` Måns Rullgård
2015-03-10  8:04               ` Pavel Machek
     [not found]                 ` <CAK5ve-K4jyBSVk1CZ8qQrFgevqdbhdsgZ1ZYX2e-t07494oq4A@mail.gmail.com>
2015-03-11  9:34                   ` Documentation: leds: clarify what 50% brightness means Pavel Machek

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