From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [Patch v2 1/6] soc: qcom: gsbi: Add support for ADM CRCI muxing Date: Mon, 02 Feb 2015 18:05:04 -0800 Message-ID: <54D02CD0.4090806@codeaurora.org> References: <1422599135-5588-1-git-send-email-agross@codeaurora.org> <1422599135-5588-2-git-send-email-agross@codeaurora.org> <54CBF9AE.6060902@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-arm-msm-owner@vger.kernel.org To: Kumar Gala Cc: Andy Gross , linux-arm-msm , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Bjorn Andersson , linux-soc@vger.kernel.org, Rob Herring List-Id: devicetree@vger.kernel.org On 01/30/15 13:48, Kumar Gala wrote: > On Jan 30, 2015, at 3:37 PM, Stephen Boyd wrot= e: > >> On 01/30/15 08:32, Kumar Gala wrote: >>> On Jan 30, 2015, at 12:25 AM, Andy Gross wr= ote: >>> >>>> Required properties if child node exists: >>>> - #address-cells: Must be 1 >>>> - #size-cells: Must be 1 >>>> - ranges: Must be present >>>> >>>> +Note: Each GSBI should have an alias correctly numbered in "alias= es" node. >>>> + >>>> Properties for children: >>>> >>>> A GSBI controller node can contain 0 or more child nodes represent= ing serial >>>> @@ -37,6 +41,10 @@ Example for APQ8064: >>>> >>>> #include >>>> >>>> + aliases { >>>> + gsbi4 =3D <&gsbi4>; >>>> + }; >>> You appear to be using the alias name to determine a index number f= or the gsbi, if that is the case, than you should probably just add a c= ell-index node to the gsbi=92s for this purpose. >>> >> I thought cell-index was "deprecated" and referred more to things li= ke >> enumerating all the devices on a bus by assigning them a unique ID. >> Aliases, on the other hand, allow us to enumerate a subset of device= s >> that share the same bus with other devices of different types. For >> example, how would I know that a device is gsbi1 vs serial1 if they = both >> used cell-index and they both had the same parent node? > I think the problem was cell-index was never well understood and abus= ed. For the example you are giving you wouldn=92t use cell-index becau= se you are talking about things that would have different compatibles. = For what it appears we really are enumerating the GSBI hardware to mat= ch some programming interface convention. If that is the case than I t= hink cell-index is proper. Can you please explain when cell-index should be used and when aliases should be used? I'm confused because I recall this message from Rob Herring[1] where it's indicated that cell-index is pretty much deprecated. I'm also interested to find out what cell means in cell-index. Does it have any relation to *-cells properties? [1] https://lkml.org/lkml/2012/11/10/102 --=20 Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project