From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35147C43387 for ; Mon, 7 Jan 2019 21:15:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7E852147C for ; Mon, 7 Jan 2019 21:15:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="vhZ5mLvq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727084AbfAGVPP (ORCPT ); Mon, 7 Jan 2019 16:15:15 -0500 Received: from lelv0142.ext.ti.com ([198.47.23.249]:34178 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726638AbfAGVPP (ORCPT ); Mon, 7 Jan 2019 16:15:15 -0500 Received: from fllv0035.itg.ti.com ([10.64.41.0]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id x07LFBWK080570; Mon, 7 Jan 2019 15:15:11 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1546895711; bh=S+3YYUlO1c/GZgpozimUPey6IMXudPor8xkeuLA1kLE=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=vhZ5mLvqP2Txx6NqwFI8uNVvF471CZ1yXUa6Rz5GhZcrewUx9MMUvrNUEqILdRjbT bgvznJJtI2JF8cH6XJsHd6GEAngtFvzK2M+MEsi6kGdXMOtCjORGADl4u3K5S26yRl DPCEKIugb314clSOy4Bha1B+YXW0Nsc4IKMmctfA= Received: from DLEE102.ent.ti.com (dlee102.ent.ti.com [157.170.170.32]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id x07LFAnF007166 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 7 Jan 2019 15:15:11 -0600 Received: from DLEE115.ent.ti.com (157.170.170.26) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Mon, 7 Jan 2019 15:15:10 -0600 Received: from dlep33.itg.ti.com (157.170.170.75) by DLEE115.ent.ti.com (157.170.170.26) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1591.10 via Frontend Transport; Mon, 7 Jan 2019 15:15:10 -0600 Received: from [172.22.110.219] (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id x07LFAhA031539; Mon, 7 Jan 2019 15:15:10 -0600 Subject: Re: [PATCH 2/2] leds: lp5024: Add the LP5024/18 RGB LED driver To: Jacek Anaszewski , =?UTF-8?B?VmVzYSBKw6TDpHNrZWzDpGluZW4=?= , Pavel Machek CC: , , , References: <8740cfd6-a6b5-ad27-313b-984a9febf18a@ti.com> <20181219201047.GA23448@amd> <54f28115-0a7d-8e9c-3bec-6e91fb3981ec@gmail.com> <986b5105-2fdb-bd25-7c8a-ca8fd1ade821@gmail.com> <7f205102-e854-f1cb-cc03-1307d1cddc87@gmail.com> <20190104201256.GA2931@amd> <90a2ed79-b437-af14-4538-430d8723cc6b@gmail.com> <38daf022-e4e4-799d-4c75-ee851315290d@gmail.com> From: Dan Murphy Message-ID: <0982f9c3-b5df-7131-8d5a-761adefd389d@ti.com> Date: Mon, 7 Jan 2019 15:15:02 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: <38daf022-e4e4-799d-4c75-ee851315290d@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jacek On 1/7/19 3:13 PM, Jacek Anaszewski wrote: > Hi Vesa, > > On 1/5/19 1:39 AM, Vesa Jääskeläinen wrote: >> Hi Jacek, >> >> On 04/01/2019 23.37, Jacek Anaszewski wrote: >>> But, aside from that hypothetic issue, we need a solution for >>> LEDn_BRIGHTNESS feature of lp5024, i.e. setting color intensity >>> via a single register write. How would you propose to address that? >> >> You could model it to something like this in device tree: >> >> led-module @ { >>      compatible = "lp5024"; >> >>      // There is in hardware setup to use either linear or >>      // logarithmic scaling: >>      //enable-logarithmic-brightness; >> >>      led0 { >>          // this will create led instance for LED0 in lp5024 >>          label = "lp-led0"; >> >>          // This specifies LED number within lp5024 >>          led-index = <0>;   // set output-base as 0*3 == 0 >> >>          element-red { >>              // refers to OUT0 >>              output-offset = <0>; >>          }; >> >>          element-green { >>              // refers to OUT1 >>              output-offset = <1>; >>          }; >> >>          element-blue { >>              // refers to OUT2 >>              output-offset = <2>; >>          }; >> >>      }; >> >>      led1 { >>          // this will create led instance for LED1 in lp5024 >>          label = "lp-led1"; >> >>          // This specifies LED number within lp5024 >>          led-index = <1>;   // set output-base as 1*3 == 3 >> >>          element-red { >>              // refers to OUT3 >>              output-offset = <0>; >>          }; >> >>          element-green { >>              // refers to OUT4 >>              output-offset = <1>; >>          }; >> >>          element-blue { >>              // refers to OUT5 >>              output-offset = <2>; >>          }; >> >>      }; >> >>      bank-led { >>          // this will create led instance for bank leds in lp5024 >>          label = "lp-bank-led"; >> >>          // configured bank led configuration >>          led-index = <2 3 4 5 6 7>; >>          // As here is list of led-indices this entry is >>          // assumed to be bank configuration. Bank mode is enable >>          // for the indices. >> >>          // set output-base as BANK A >> >>          element-red { >>              // refers to BANK A >>              output-offset = <0>; >>          }; >> >>          element-green { >>              // refers to BANK B >>              output-offset = <1>; >>          }; >> >>          element-blue { >>              // refers to BANK C >>              output-offset = <2>; >>          }; >>      }; >> }; >> >> This would then create three led instances and each led instance has brightness setting and that goes straight to hardware. >> >> If one would want to override hardware control for brightness then I suppose you would define in led node something like: >> >>      brightness-model = "hsl" >> >> This would then pick red, green and blue elements for hsl calculations and others color elements for linear. LED specific hardware brightness would then be either 0 or 0xFF depending if all of LED color elements are zero or not. >> >> Would that kind of model work? > > I'd prefer to have single RGB LED device. And your DT design > is unnecessarily complex and a bit confusing. +1 to that comment > > Also, you provided scarce information about sysfs interface. > It would be nice to see the sequence of commands. > -- ------------------ Dan Murphy