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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 704B8C2B9F7 for ; Tue, 25 May 2021 02:04:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5044661209 for ; Tue, 25 May 2021 02:04:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230022AbhEYCFw (ORCPT ); Mon, 24 May 2021 22:05:52 -0400 Received: from twspam01.aspeedtech.com ([211.20.114.71]:18712 "EHLO twspam01.aspeedtech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230008AbhEYCFw (ORCPT ); Mon, 24 May 2021 22:05:52 -0400 Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 14P1pJMg007540; Tue, 25 May 2021 09:51:19 +0800 (GMT-8) (envelope-from jamin_lin@aspeedtech.com) Received: from aspeedtech.com (192.168.100.253) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 25 May 2021 10:04:16 +0800 Date: Tue, 25 May 2021 10:04:13 +0800 From: Jamin Lin To: Joel Stanley 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" Subject: Re: [PATCH 1/3] i2c: aspeed: avoid new registers definition of AST2600 Message-ID: <20210525020412.GA2489@aspeedtech.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [192.168.100.253] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) X-DNSRBL: X-MAIL: twspam01.aspeedtech.com 14P1pJMg007540 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org The 05/24/2021 02:34, Joel Stanley wrote: > 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 Thanks for your suggestion. I will submit the new i2c driver for AST2600 soon. Jamin