Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933774AbcKJOeL (ORCPT ); Thu, 10 Nov 2016 09:34:11 -0500 Received: from foss.arm.com ([217.140.101.70]:49752 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933668AbcKJOeK (ORCPT ); Thu, 10 Nov 2016 09:34:10 -0500 Subject: Re: [PATCH v5 6/8] Documentation: bindings: add compatible specific to legacy SCPI protocol To: Rob Herring References: <1478148731-11712-1-git-send-email-sudeep.holla@arm.com> <1478148731-11712-7-git-send-email-sudeep.holla@arm.com> <20161110012249.ed56ik6kdffoikym@rob-hp-laptop> <14e563ae-36c5-4bf9-0d51-3b07830de3db@arm.com> Cc: Sudeep Holla , Neil Armstrong , Olof Johansson , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , linux-amlogic@lists.infradead.org From: Sudeep Holla Organization: ARM Message-ID: <7ccc12bc-9a05-47e3-8ab8-d1b0ad31159e@arm.com> Date: Thu, 10 Nov 2016 14:34:07 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2597 Lines: 69 On 10/11/16 14:12, Rob Herring wrote: > On Thu, Nov 10, 2016 at 4:26 AM, Sudeep Holla wrote: >> >> >> On 10/11/16 01:22, Rob Herring wrote: >>> >>> On Wed, Nov 02, 2016 at 10:52:09PM -0600, Sudeep Holla wrote: >>>> >>>> This patch adds specific compatible to support legacy SCPI protocol. >>>> >>>> Cc: Rob Herring >>>> Signed-off-by: Sudeep Holla >>>> --- >>>> Documentation/devicetree/bindings/arm/arm,scpi.txt | 4 +++- >>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/Documentation/devicetree/bindings/arm/arm,scpi.txt >>>> b/Documentation/devicetree/bindings/arm/arm,scpi.txt >>>> index d1882c4540d0..ebd03fc93135 100644 >>>> --- a/Documentation/devicetree/bindings/arm/arm,scpi.txt >>>> +++ b/Documentation/devicetree/bindings/arm/arm,scpi.txt >>>> @@ -7,7 +7,9 @@ by Linux to initiate various system control and power >>>> operations. >>>> >>>> Required properties: >>>> >>>> -- compatible : should be "arm,scpi" >>>> +- compatible : should be >>>> + * "arm,scpi" : For implementations complying to SCPI v1.0 or >>>> above >>>> + * "arm,legacy-scpi" : For implementations complying pre SCPI v1.0 >>> >>> >>> I'd prefer that we explicitly enumerate the old versions. Are there >>> many? >>> >> >> I understand your concern, but this legacy SCPI protocol was not >> officially released. It was just WIP which vendors picked up from very >> early releases. Since they are not numbered, it's hard to have specific >> compatibles with different versions until v1.0. That's one of the reason >> to retain platform specific compatible so that we can add any quirks >> based on them if needed. >> >> I will probably add these information in the commit log so that it's >> clear why we can't do version based compatible. > > This is exactly my point. By enumerate, I meant having platform > specific compatibles. Having "arm,legacy-scpi" is pointless because > who knows what version they followed and they may all be different. > OK, but IIUC Olof's concern wanted a generic one along with the platform specific compatible which kind of makes sense as so far we have seen some commonality between Amlogic and Rockchip. E.g. Amlogic follows most of the legacy protocol though it deviates in couple of things which we can handle with platform specific compatible (in the following patch in the series). When another user(Rockchip ?) make use of this legacy protocol, we can start using those platform specific compatible for deviations only. Is that not acceptable ? -- Regards, Sudeep