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=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 D49AEC47080 for ; Mon, 24 May 2021 02:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B749D61139 for ; Mon, 24 May 2021 02:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232191AbhEXCga (ORCPT ); Sun, 23 May 2021 22:36:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231867AbhEXCg3 (ORCPT ); Sun, 23 May 2021 22:36:29 -0400 Received: from mail-qk1-x729.google.com (mail-qk1-x729.google.com [IPv6:2607:f8b0:4864:20::729]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3556CC061574; Sun, 23 May 2021 19:35:01 -0700 (PDT) Received: by mail-qk1-x729.google.com with SMTP id j189so4924467qkf.2; Sun, 23 May 2021 19:35:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jms.id.au; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jJuutPWSYZAO28hQHvByxbn0puUm3ID8Bjg9Q7zuB7I=; b=gyn3CX5lKh7USWncJLEqq50UPHkDuQtOOqqvL9MqVnZjhmT5Y7orqLXwlWHS8bWlbm u49FBbUwu3mSCq+sY/aDG8zv7KOpP/YNiBdr8myFB86xFTR2RRblZiWODTK8z0x2CASk 9gvfahTH8t+zsivcrREBshWk/QZhFbE7BZCEo= 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=jJuutPWSYZAO28hQHvByxbn0puUm3ID8Bjg9Q7zuB7I=; b=FD6+aYGAoNcdvKgYGNhu093/53lqpRyv0Nd0lC/QFZ/HMmZN4XOm7XsTeIPJSF6q6a aVMa8abomaJDsPn00BO0SNYWybEZ+sa0EA6xTpll/eVBizf+1tUJ2PeFON6HYSqa2LA1 Zo7EsU7/ga/pXJ9OwuuOdd0sfDpptNLHgFNDD6WuleDVPMYlFp9UZmAC/HMdSMmJfgCQ +jvq+65UjncfpDz6w9TrdGmxVhUsexwUoX1hTzIzHWt3fIYc7o4NSxqe9cuhfKGeFast vCd4io9jj0hAHfOXmPfqKM+UoeL3J/muWiKDb/HeFnoxdgD/Bdkaef6dozqKvEdo7sHR gLcw== X-Gm-Message-State: AOAM533tkFH8ZcDoqzNcLoZ9RGejBr1PdbmWqbfP3jk1CVk0V/y9FXEd 32FQ4zAtT3Ccst/qR2v2u05II2o6ZCdMBPVkgCY= X-Google-Smtp-Source: ABdhPJxlXMLLdn72u71hp/PqNVkvxZeVT04/cLpqvway+mxqT+thSozVVCebxD5BCKvPl0m1TBVjHyy5U+KsEdKwvf4= X-Received: by 2002:ae9:e105:: with SMTP id g5mr28234682qkm.55.1621823699912; Sun, 23 May 2021 19:34:59 -0700 (PDT) MIME-Version: 1.0 References: <20210519080436.18975-1-jamin_lin@aspeedtech.com> <20210519080436.18975-2-jamin_lin@aspeedtech.com> <20210520033140.GA3656@aspeedtech.com> <20210521020033.GB19153@taoren-ubuntu-R90MNF91> <20210524015310.GA2591@aspeedtech.com> In-Reply-To: <20210524015310.GA2591@aspeedtech.com> From: Joel Stanley Date: Mon, 24 May 2021 02:34:47 +0000 Message-ID: Subject: Re: [PATCH 1/3] i2c: aspeed: avoid new registers definition of AST2600 To: Jamin Lin Cc: Tao Ren , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , "moderated list:ARM/ASPEED MACHINE SUPPORT" , "moderated list:ARM/ASPEED I2C DRIVER" , Brendan Higgins , open list , Rob Herring , Rayn Chen , "open list:I2C SUBSYSTEM HOST DRIVERS" , Steven Lee , "moderated list:ARM/ASPEED MACHINE SUPPORT" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 24 May 2021 at 01:53, Jamin Lin wrote: > > The 05/21/2021 02:00, Tao Ren wrote: > > Hi Jamin, > > > > On Thu, May 20, 2021 at 11:31:41AM +0800, Jamin Lin wrote: > > > The 05/19/2021 22:59, Joel Stanley wrote: > > > > On Wed, 19 May 2021 at 08:05, Jamin Lin wrote: > > > > > > > > > > The register definition between AST2600 A2 and A3 is different. > > > > > This patch avoid new registers definition of AST2600 to use > > > > > this driver. We will submit the path for the new registers > > > > > definition of AST2600. > > > > > > > > The AST2600 v9 datasheet says that bit 2 selects between old and new > > > > register sets, and that the old register set is the default. > > > > > > > > Has the default changed for the A3?, and the datasheet is incorrect? > > > > > > > > Does the A3 still support the old register set? > > > > > > > We suggest user to use the new i2c driver for AST2600 and we will sumbit > > > it. This driver is used to AST2500 and AST2400 SOCs. Change this > > > driver to check global register of i2c to avoid user build the wrong driver. > > > > If I understand correctly, the answer implies old register set is still > > supported in A3 although aspeed suggest people using the new driver/mode? > > > > Can you please share more context behind the suggestion? Such as new > > register mode has better performance? Or some known issues that were > > deteted in old mode are fixed in new register mode? > > > Yes, AST2600 A1, A2 and A3 support both old and new register set. The difference > between old and new register set are the register address and supported registers. > User can choose to use both old and new register set. However, ASPEED would like to > change new register set by default for AST2600. We can certainly make the driver for the new register set the default for AST2600 when the new driver is merged. I disagree that we should introduce a run time check to fail to probe the old driver. Please do not merge this patch. Please focus your effort on getting the new driver merged instead. Cheers, Joel