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 B3FB3C54EE9 for ; Thu, 22 Sep 2022 15:44:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231985AbiIVPoo (ORCPT ); Thu, 22 Sep 2022 11:44:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231995AbiIVPoR (ORCPT ); Thu, 22 Sep 2022 11:44:17 -0400 Received: from bmailout2.hostsharing.net (bmailout2.hostsharing.net [83.223.78.240]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8CE6A102E03 for ; Thu, 22 Sep 2022 08:43:55 -0700 (PDT) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by bmailout2.hostsharing.net (Postfix) with ESMTPS id DC2E728384A31; Thu, 22 Sep 2022 17:43:53 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id C36DB4E9FF; Thu, 22 Sep 2022 17:43:53 +0200 (CEST) Date: Thu, 22 Sep 2022 17:43:53 +0200 From: Lukas Wunner To: Greg Kroah-Hartman Cc: Matthias Schiffer , Roosen Henri , linux-serial@vger.kernel.org, Ilpo Jarvinen , Jiri Slaby , Lino Sanfilippo , David Laight , Maarten Brock , Jan Kiszka , Su Bao Cheng , Chao Zeng , Peter Hung , Daniel Golle , "Codrin.Ciubotariu@microchip.com" , Sherry Sun , Serge Semin , Ricardo Ribalda , Dario Binacchi , Bich Hemon , Marek Vasut , Vicente Bergas Subject: Re: [PATCH v2] serial: Deassert Transmit Enable on probe in driver-specific way Message-ID: <20220922154353.GA3559@wunner.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Thu, Sep 22, 2022 at 04:43:51PM +0200, Greg Kroah-Hartman wrote: > On Wed, Sep 21, 2022 at 06:39:33AM +0200, Lukas Wunner wrote: > > When a UART port is newly registered, uart_configure_port() seeks to > > deassert RS485 Transmit Enable by setting the RTS bit in port->mctrl. > > However a number of UART drivers interpret a set RTS bit as *assertion* > > instead of deassertion: Affected drivers include those using > > serial8250_em485_config() (except 8250_bcm2835aux.c) and some using > > mctrl_gpio (e.g. imx.c). > > > > Since the interpretation of the RTS bit is driver-specific, it is not > > suitable as a means to centrally deassert Transmit Enable in the serial > > core. Instead, the serial core must call on drivers to deassert it in > > their driver-specific way. One way to achieve that is to call > > ->rs485_config(). It implicitly deasserts Transmit Enable. > > > > So amend uart_configure_port() and uart_resume_port() to invoke > > uart_rs485_config(). That allows removing calls to uart_rs485_config() > > from drivers' ->probe() hooks and declaring the function static. [...] > > This message never made it to lore.kernel.org, so I can't seem to apply > it using `b4`. > > Can you resend it so that it does make it to the public archives? Yes, both v1 and v2 didn't make it to the mailing list archive. My suspicion is that the Cc: line was probably too long. I resent as v3 with only you in To: and the mailing list in Cc: and this time it went through: https://lore.kernel.org/linux-serial/2de36eba3fbe11278d5002e4e501afe0ceaca039.1663860626.git.lukas@wunner.de/ On the bright side, v2 contained an embarrassing checkpatch issue (superfluous newline) and resending as v3 provided a welcome opportunity to fix that. :) Thanks, Lukas