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=-5.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 563F0C76186 for ; Mon, 29 Jul 2019 21:57:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B84C20C01 for ; Mon, 29 Jul 2019 21:57:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="sVE9zpEA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389082AbfG2V5b (ORCPT ); Mon, 29 Jul 2019 17:57:31 -0400 Received: from mail-lf1-f66.google.com ([209.85.167.66]:41863 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728185AbfG2V5a (ORCPT ); Mon, 29 Jul 2019 17:57:30 -0400 Received: by mail-lf1-f66.google.com with SMTP id 62so38267033lfa.8 for ; Mon, 29 Jul 2019 14:57:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=WhB+RZ2P4weNNxlV3JiaH27Cy16VoQbodVkM+yi6FAA=; b=sVE9zpEAJSM4jgNF+JxW1v7N1fcEZmKVkBwXW6KNsVWmVQFLHqD9d+xWPT9I2jAv7d TWVaNyRqpnOg3/0m2gk7Ch7jfca9Jh7XmgTvTp/mhbO/osy8RPidS52ZbciVLnLEwdVN 13aomLVoHqKP8mi75hzRriyJh55sc4+nlArQq/OmMsDigdVM12/m5kKoc0QeQ0A/N+rn uT5q2dRFCTZxrWDs9LEKNvSy227d40I8Q4tKWwgJf09KBFWvYLj22dKO7HSBJthn38/j qYBSQpexpirObv7xVzyDVw0nZYVjTHFYX1mCs0JG/ZipMEBdkq6//TrU3cy7vGuxUxj1 Nt8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=WhB+RZ2P4weNNxlV3JiaH27Cy16VoQbodVkM+yi6FAA=; b=kekW//8HHhdmejxuSXZOPkvb6y9GrLpq/WHhuxu4ANHHwW+7S6WVREwXjNUGpooRZx j4chebYmcP3qZ/zoo+BCJhUg0nuPdQA88KXynGnM4t7uFk3ZW80XlVJUxFz9NIvvv5AL 96sU3qQ0QskgOZGeIXFOjhAQ+EW3YkOdN9p9OsCJNazH29FY95hov1ynaE5T27hNedjX B/6HyqAuz5hIcmwtI8ZFPlS6LYhOg3cveFQusP3YAIAVxA2Ol0Mdkl7LSyutppvHbRWu EZgv+EOuXzuVcf/03DpT90FYex7wOBrYgkd3KPM9p5TFxbJNJg740IgKI/dsMeX/uolR 7W3Q== X-Gm-Message-State: APjAAAX5SVYmHNpFKDDAI2SM+1KkGWjSPxk6q/ixptXPlAo5TPWdlwYj EMywYHLKZxGXO0GITU+LWKinop4TFnrNXrUdRKu1HA== X-Google-Smtp-Source: APXvYqyBnwkv1VRTZGXZco57yirARpTFLPJRJ/RvgElvK8IXTHcFCH30jet7L01e4aA0VROLzr8OPXOGn2X/EdVc1D0= X-Received: by 2002:ac2:4891:: with SMTP id x17mr54444437lfc.60.1564437448905; Mon, 29 Jul 2019 14:57:28 -0700 (PDT) MIME-Version: 1.0 References: <1563564291-9692-1-git-send-email-hongweiz@ami.com> <1563564291-9692-2-git-send-email-hongweiz@ami.com> In-Reply-To: From: Linus Walleij Date: Mon, 29 Jul 2019 23:57:16 +0200 Message-ID: Subject: Re: [v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support To: Andrew Jeffery Cc: Hongwei Zhang , "open list:GPIO SUBSYSTEM" , Joel Stanley , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , linux-aspeed , Bartosz Golaszewski , Rob Herring , Mark Rutland , "linux-kernel@vger.kernel.org" , Linux ARM Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 29, 2019 at 2:19 AM Andrew Jeffery wrote: > The behaviour is to periodically emit the state of all enabled GPIOs > (i.e. the ngpios value), one per bus clock cycle. There's no explicit > addressing scheme, the protocol encodes the value for a given GPIO > by its position in the data stream relative to a pulse on the "load data" > (LD) line, whose envelope covers the clock cycle for the last GPIO in > the sequence. Similar to SPI the bus has both out and in lines, which > cater to output/input GPIOs. > > A rough timing diagram for a 16-GPIO configuration looks like what > I've pasted here: > > https://gist.github.com/amboar/c9543af1957854474b8c05ab357f0675 OK that is complex. I agree we need to keep this driver together. Yours, Linus Walleij