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 72637C6FA82 for ; Thu, 22 Sep 2022 16:31:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232001AbiIVQbo (ORCPT ); Thu, 22 Sep 2022 12:31:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232203AbiIVQbT (ORCPT ); Thu, 22 Sep 2022 12:31:19 -0400 Received: from bmailout1.hostsharing.net (bmailout1.hostsharing.net [IPv6:2a01:37:1000::53df:5f64:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A90BE7C27 for ; Thu, 22 Sep 2022 09:30:48 -0700 (PDT) Received: from h08.hostsharing.net (h08.hostsharing.net [IPv6:2a01:37:1000::53df:5f1c:0]) (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 bmailout1.hostsharing.net (Postfix) with ESMTPS id CAEEA3004D796; Thu, 22 Sep 2022 18:30:42 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id B0BDEBB; Thu, 22 Sep 2022 18:30:42 +0200 (CEST) Date: Thu, 22 Sep 2022 18:30:42 +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: <20220922163042.GA12887@wunner.de> References: <20220922154353.GA3559@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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 06:06:56PM +0200, Greg Kroah-Hartman wrote: > On Thu, Sep 22, 2022 at 05:43:53PM +0200, Lukas Wunner wrote: > > 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. :) > > v3 did not have a changelog :( > > v4? Well, the changelog is above. (Only the superfluous newline was removed in v3 vis-à-vis v2.) Here's a v4 with full changelog: https://lore.kernel.org/linux-serial/2de36eba3fbe11278d5002e4e501afe0ceaca039.1663863805.git.lukas@wunner.de/