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 01C65C43334 for ; Tue, 19 Jul 2022 12:17:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239303AbiGSMQ7 (ORCPT ); Tue, 19 Jul 2022 08:16:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239006AbiGSMNn (ORCPT ); Tue, 19 Jul 2022 08:13:43 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0AF6915A03; Tue, 19 Jul 2022 05:04:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6FA29B81B2C; Tue, 19 Jul 2022 12:04:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95D53C341C6; Tue, 19 Jul 2022 12:04:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658232262; bh=zjM5uGp2WvyhbyguXiRP4U+eFsN5c6pbeoztRa9fAj0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XvI1b1Z+Ct9dwZJnUKYTRU8htsw7B6TiuvJV69l5zs2nubMLytmTsrX1tdrvhRa+H YLLXYKC3eHYaobMzyldJCxkhB9OHWGu121PQAixq/V/s4DJqznnoq6Uld32vTm7bIS QwRZ1ToC/5kteScPVsFDY+NMEmi49EY1bOzDaf5o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, stable , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Subject: [PATCH 5.4 69/71] serial: stm32: Clear prev values before setting RTS delays Date: Tue, 19 Jul 2022 13:54:32 +0200 Message-Id: <20220719114559.346970211@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220719114552.477018590@linuxfoundation.org> References: <20220719114552.477018590@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ilpo Järvinen commit 5c5f44e36217de5ead789ff25da71c31c2331c96 upstream. The code lacks clearing of previous DEAT/DEDT values. Thus, changing values on the fly results in garbage delays tending towards the maximum value as more and more bits are ORed together. (Leaving RS485 mode would have cleared the old values though). Fixes: 1bcda09d2910 ("serial: stm32: add support for RS485 hardware control mode") Cc: stable Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220627150753.34510-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -73,6 +73,8 @@ static void stm32_config_reg_rs485(u32 * *cr3 |= USART_CR3_DEM; over8 = *cr1 & USART_CR1_OVER8; + *cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK); + if (over8) rs485_deat_dedt = delay_ADE * baud * 8; else