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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F885C7113B for ; Thu, 24 Aug 2023 10:52:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238002AbjHXKwP (ORCPT ); Thu, 24 Aug 2023 06:52:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231362AbjHXKvp (ORCPT ); Thu, 24 Aug 2023 06:51:45 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1BFA910DA; Thu, 24 Aug 2023 03:51:42 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 16F861042; Thu, 24 Aug 2023 03:52:22 -0700 (PDT) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BA0503F740; Thu, 24 Aug 2023 03:51:39 -0700 (PDT) Date: Thu, 24 Aug 2023 11:51:37 +0100 From: Sudeep Holla To: Linus Walleij Cc: "Peng Fan (OSS)" , oleksii_moisieiev@epam.com, Sudeep Holla , aisheng.dong@nxp.com, festevam@gmail.com, ping.bai@nxp.com, s.hauer@pengutronix.de, shawnguo@kernel.org, kernel@pengutronix.de, linux-imx@nxp.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, Peng Fan Subject: Re: [RFC] scmi: pinctrl: support i.MX9 Message-ID: <20230824105137.xqkwi4xvmjoidexh@bogus> References: <20230824070611.3335107-1-peng.fan@oss.nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Linus, Thanks a lot for the quick response. On Thu, Aug 24, 2023 at 10:43:20AM +0200, Linus Walleij wrote: > On Thu, Aug 24, 2023 at 9:01 AM Peng Fan (OSS) wrote: > > > This patch is just to introduce i.MX support to see whether people have > > comments for the design. > > Very interesting! > > > The binding format: > > > > dts: > > pinctrl_uart1: uart1grp { > > fsl,pins = < > > MX93_PAD_UART1_RXD__LPUART1_RX 0x31e > > MX93_PAD_UART1_TXD__LPUART1_TX 0x31e > > >; > > }; > > > > i.MX pinctrl not use generic pinconf, this has been agreeed by > > maintainers before. > > Yes, it has historical reasons. > Good to know. > > So after moving to SCMI, we will still > > keep the same binding format, and i.MX SCMI firmware also use same > > format when configure registers. So we need to use i.MX specific > > dt_node_to_map function. > > I thought the idea with SCMI was to abstract and hide the characteristics of > the underlying hardware. I.e. the firmware is to present groups and > functions and generic config options and then the driver will use these. > Correct. > This patch, it seems, creates a hybrid between the old freescale driver > and the SCMI firmware communication link where the SCMI is just a > transport mechanism to something inside SCMI that poke the same > registers that userspace could poke, if it could only access these > registers. > > I.e using SCMI on this platform isn't creating any abstraction of the > pin control hardware, it is merely making things more complex and > also slower bymaking the registers only accessible from this SCMI link. > Agreed. I don't have much knowledge on generic pinmux conf and suggested Peng to post the RFC to start the discussion instead of getting blocked by me during some internal/private discussions as the main intention for him was upstreaming the changes. I am against the idea of mixing platform specific changes the way it is done here but since I didn't have much knowledge on pinmux conf to suggest/provide any useful feedback I suggested to trigger this discussion. > But I could have misunderstood it, so please correct me! +1 -- Regards, Sudeep