From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Subject: Re: [PATCH v1] leds: Clarify supported chips by LM355x driver Date: Tue, 30 Jan 2018 21:04:30 +0100 Message-ID: <15971fbb-2c6d-5c15-d5d7-1718af904ebb@gmail.com> References: <20180126073828.70597-1-andriy.shevchenko@linux.intel.com> <0bbb47ba-4b4f-263f-a8f3-aad13d7bd753@gmail.com> <1517149809.7000.1288.camel@linux.intel.com> <5968dfb2-8bf9-917f-4299-47bf1cd97124@gmail.com> <1517310500.7000.1319.camel@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wm0-f45.google.com ([74.125.82.45]:34042 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752793AbeA3UFp (ORCPT ); Tue, 30 Jan 2018 15:05:45 -0500 Received: by mail-wm0-f45.google.com with SMTP id j21so5225929wmh.1 for ; Tue, 30 Jan 2018 12:05:44 -0800 (PST) In-Reply-To: <1517310500.7000.1319.camel@linux.intel.com> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Andy Shevchenko , Richard Purdie , Pavel Machek , linux-leds@vger.kernel.org, Sakari Ailus On 01/30/2018 12:08 PM, Andy Shevchenko wrote: > On Mon, 2018-01-29 at 21:46 +0100, Jacek Anaszewski wrote: >> On 01/28/2018 03:30 PM, Andy Shevchenko wrote: >>> On Fri, 2018-01-26 at 21:39 +0100, Jacek Anaszewski wrote: >>>> On 01/26/2018 08:38 AM, Andy Shevchenko wrote: >>>>> + Note, LM3555 is driven by AS3645A. >>>> >>>> Could you please provide more details on this relationship? >>>> Looking at the datasheet it seems that both chips are standalone >>>> and controlled via I2C and/or via GPIO in case of LM3555. >>> >>> The only difference I see looking in datasheets again that AS3645A >>> supports dual-led mode, by using STROBE signal in case of parallel >>> interface or thru additional bits in I2C mode. >>> >>> Can you be more specific what exactly makes you feel that they are >>> not >>> compatible? >> >> The expression "LM3555 is driven by AS3645A" brings on mind rather >> some type of hardware dependency between chips than drivers >> similarity. >> >> Now I understand that you meant that both devices can be driven by any >> of leds-lm355x or leds-as3645a driver, am I right? > > No. The chip in question is LM3555, and it's handled only in as3645a > driver. > >> I suspected that I got something entirely wrong here, especially >> that both you and Pavel agreed. >> >> But, given that it turned out that leds-lm355x.c doesn't support >> LM3555 and its documentation [3] indeed shows the affinity with >> AS3645, I suppose that this patch is a result of a premature >> conclusion drawn basing on the driver's description rather than its >> capabilities. >> >> [3] http://www.ti.com/lit/ds/symlink/lm3555.pdf >> >> Effectively, the only sensible change seems to be: >> >> - tristate "LED support for LM355x Chips, LM3554 and LM3556" >> + tristate "LED support for LM3554 and LM3556 chips" >> depends on LEDS_CLASS && I2C >> select REGMAP_I2C >> help >> - This option enables support for LEDs connected to LM355x. >> - LM355x includes Torch, Flash and Indicator functions. >> + This option enables support for LEDs connected to LM3554 >> + and LM3556. It includes Torch, Flash and Indicator >> functions. > > I like patch Pavel sent previously. It feels more comprehensive than > this one. Right. The patch subject and description will have to be tweaked a bit then. I'll apply it once it is officially submitted. -- Best regards, Jacek Anaszewski