Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752583AbbBYIZ0 (ORCPT ); Wed, 25 Feb 2015 03:25:26 -0500 Received: from mail-ob0-f170.google.com ([209.85.214.170]:43449 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750771AbbBYIZY (ORCPT ); Wed, 25 Feb 2015 03:25:24 -0500 MIME-Version: 1.0 In-Reply-To: <20150219211424.GN13603@saruman.tx.rr.com> References: <20150219211424.GN13603@saruman.tx.rr.com> Date: Wed, 25 Feb 2015 09:25:24 +0100 X-Google-Sender-Auth: xIMj0zINyP_5ROX8L4FrqaCX3Ps Message-ID: Subject: Re: "advanced" LED controllers From: Geert Uytterhoeven To: Felipe Balbi Cc: Bryan Wu , Richard Purdie , "linux-leds@vger.kernel.org" , Linux Kernel Mailing List , Linux OMAP Mailing List , "linux-gpio@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1798 Lines: 38 CC linux-gpio, as this looks like the LED equivalent of bulk gpio? On Thu, Feb 19, 2015 at 10:14 PM, Felipe Balbi 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). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/