From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934622AbdEWBWE (ORCPT ); Mon, 22 May 2017 21:22:04 -0400 Received: from conssluserg-05.nifty.com ([210.131.2.90]:27528 "EHLO conssluserg-05.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753115AbdEWBV7 (ORCPT ); Mon, 22 May 2017 21:21:59 -0400 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-05.nifty.com v4N1LoUh010626 X-Nifty-SrcIP: [209.85.161.173] MIME-Version: 1.0 In-Reply-To: References: From: Masahiro Yamada Date: Tue, 23 May 2017 10:21:49 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [DT Question] "simple-mfd" DT binding To: Linus Walleij Cc: "devicetree@vger.kernel.org" , Rob Herring , Arnd Bergmann , Lee Jones , Linux Kernel Mailing List , linux-arm-kernel , Mark Rutland Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lee, Linus, Thanks for your comments! 2017-05-22 17:43 GMT+09:00 Linus Walleij : > On Mon, May 22, 2017 at 3:29 AM, Masahiro Yamada > wrote: > >> Because "simple-bus" indicates that child nodes are >> simply memory mapped, but the node "register-bit-led" >> can not be memory-mapped. >> So, "simple-mfd" can not be replaced "simple-bus" here. > > Yeah... just like Lee points out, you are spot on, this is exactly > the reason why we created "simple-mfd" in the first place > IIRC. OK, Linux treats simple-bus and simple-mfd in the same way as far as I see drivers/of/platform.c Perhaps, can we document the difference between simple-bus and simple-mfd clearly? For example, "Unlike simple-bus, it is legitimate that simple-mfd has subnodes without reg property" I think this is typical when "simple-mfd" is used together with "syscon". The child devices will use regmap of the parent node. I'd like to be sure this is valid usage. -- Best Regards Masahiro Yamada