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 99CD5C433F5 for ; Sun, 2 Jan 2022 10:07:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232231AbiABKHQ (ORCPT ); Sun, 2 Jan 2022 05:07:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232210AbiABKHP (ORCPT ); Sun, 2 Jan 2022 05:07:15 -0500 Received: from bmailout3.hostsharing.net (bmailout3.hostsharing.net [IPv6:2a01:4f8:150:2161:1:b009:f23e:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 219A1C061574; Sun, 2 Jan 2022 02:07:13 -0800 (PST) Received: from h08.hostsharing.net (h08.hostsharing.net [IPv6:2a01:37:1000::53df:5f1c:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by bmailout3.hostsharing.net (Postfix) with ESMTPS id 14395100DA1A7; Sun, 2 Jan 2022 11:07:11 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id E21914A82A; Sun, 2 Jan 2022 11:07:10 +0100 (CET) Date: Sun, 2 Jan 2022 11:07:10 +0100 From: Lukas Wunner To: jmades Cc: gregkh@linuxfoundation.org, Russell King , Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Lino Sanfilippo , Philipp Rosenberger Subject: Re: [PATCH] Bugfix RTS line config in RS485 mode is overwritten in pl011_set_mctrl() function. Message-ID: <20220102100710.GA29858@wunner.de> References: <20211231171516.18407-1-jochen@mades.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211231171516.18407-1-jochen@mades.net> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 31, 2021 at 05:15:14PM +0000, jmades wrote: > Based on the "0001-serial-amba-pl011-add-RS485-support.patch" this change is necesarry otherwise the RTS-line will be pulled up in SER_RS485_RTS_BEFORE_SEND mode before sending data. This hinders the driver to receive data, f.ex. when the device is an RS485 slave device. > > Signed-off-by: jmades Patch is correct, but commit message could be improved: * Subject should be in imperative mood (by convention), it should be prepended by "serial: pl011: " (in line with previous commits touching this driver, use "git log --oneline amba-pl011.c") and the trailing dot is unnecessary, e.g.: "serial: pl011: Fix incorrect rs485 RTS polarity on set_mctrl" * Commit message should be wrapped at 72 characters (so that it appears centered when displayed with "git log" on an 80 chars terminal). The reference to "0001-serial-amba-pl011-add-RS485-support.patch" should be replaced with a reference to the offending commit, e.g.: "Commit 8d479237727c ("serial: amba-pl011: add RS485 support") sought to keep RTS deasserted on set_mctrl if rs485 is enabled. However it did so only if deasserted RTS polarity is high. Fix it in case it's low." Feel free to copy this to a v2 of your patch and amend as you see fit. * Add tags for the offending commit: Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support") Cc: stable@vger.kernel.org # v5.15+ * Be sure to cc the author of the offending commit. Thanks, Lukas > --- > drivers/tty/serial/amba-pl011.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index 537f37ac4..1749c1498 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c > @@ -1646,8 +1646,12 @@ static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) > container_of(port, struct uart_amba_port, port); > unsigned int cr; > > - if (port->rs485.flags & SER_RS485_ENABLED) > - mctrl &= ~TIOCM_RTS; > + if (port->rs485.flags & SER_RS485_ENABLED) { > + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) > + mctrl &= ~TIOCM_RTS; > + else > + mctrl |= TIOCM_RTS; > + } > > cr = pl011_read(uap, REG_CR);