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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 4490BC0044C for ; Sat, 3 Nov 2018 10:22:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0A1F2081F for ; Sat, 3 Nov 2018 10:21:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0A1F2081F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jic23.retrosnub.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728196AbeKCTcs (ORCPT ); Sat, 3 Nov 2018 15:32:48 -0400 Received: from saturn.retrosnub.co.uk ([46.235.226.198]:54860 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726711AbeKCTcr (ORCPT ); Sat, 3 Nov 2018 15:32:47 -0400 Received: from archlinux (cpc91196-cmbg18-2-0-cust659.5-4.cable.virginm.net [81.96.234.148]) by saturn.retrosnub.co.uk (Postfix; Retrosnub mail submission) with ESMTPSA id EA8029E6A33; Sat, 3 Nov 2018 10:21:54 +0000 (GMT) Date: Sat, 3 Nov 2018 10:21:53 +0000 From: Jonathan Cameron To: Chen-Yu Tsai Cc: Rob Herring , Lars-Peter Clausen , "open list:THERMAL" , linux-iio@vger.kernel.org, Linus Walleij , Sebastian Reichel , linux-kernel , Vasily Khoruzhick , Quentin Schulz , devicetree , oskari@lemmela.net, linux-gpio@vger.kernel.org, Hartmut Knaack , Lee Jones , linux-arm-kernel , Quentin Schulz Subject: Re: [PATCH v5 04/11] dt-bindings: iio: adc: add AXP803 ADC bindings Message-ID: <20181103102153.4f0481ad@archlinux> In-Reply-To: References: <20181023185330.10472-1-oskari@lemmela.net> <20181023185330.10472-5-oskari@lemmela.net> <20181024135633.GA342@bogus> <20181028154011.04efdecf@archlinux> <20181029130757.m5okrfvusjl5fu5m@qschulz> X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 31 Oct 2018 10:29:59 +0800 Chen-Yu Tsai wrote: > On Mon, Oct 29, 2018 at 9:10 PM Quentin Schulz > wrote: > > > > Hi Jonathan, > > > > On Sun, Oct 28, 2018 at 03:40:11PM +0000, Jonathan Cameron wrote: > > > On Wed, 24 Oct 2018 08:56:33 -0500 > > > Rob Herring wrote: > > > > > > > On Tue, 23 Oct 2018 21:53:23 +0300, Oskari Lemmela wrote: > > > > > The AXP803 ADC is compatible with AXP813 ADC, but add > > > > > specific compatible for it. > > > > > > > > > > Signed-off-by: Oskari Lemmela > > > > > --- > > > > > Documentation/devicetree/bindings/iio/adc/axp20x_adc.txt | 2 ++ > > > > > 1 file changed, 2 insertions(+) > > > > > > > > > > > > > Reviewed-by: Rob Herring > > > > > > This doesn't seem to have any dependencies with the other patches > > > so applied to the togreg branch of iio.git and pushed out as testing > > > for the autobuilders to ignore. However I am a little curious to know > > > why we would add the ID and then not use it (that I can see)? > > > > > > > Sometimes with Allwinner (and X-Powers), two IPs seem identical until we > > discover something that is slightly different. When this happens, we > > have to add a compatible to differentiate both. However, we would also > > need to change the Device Tree to change the compatible. We would need > > to handle the driver behaviour for both Device Trees. > > > > So better anticipate a possible difference so that we don't have to do > > some hacks in the driver to handle the device correctly. > > > > As always, Chen-Yu or Maxime may know better so I'm just stating what I > > seem to recall. > > With Allwinner stuff (X-Powers included), sometimes the documents are > incomplete or have errors. We tend to add a model-specific compatible > just in case things turn out not to be so compatible, unless someone > has triple-checked everything, documents and actual hardware included. > > However we don't actually document these, so this patch isn't strictly > needed. (I suppose this might annoy the device tree binding maintainers.) > > ChenYu I don't think it does any harm so I'll leave it in place. Thanks for the explanations. Jonathan