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 X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FB7FC38A29 for ; Thu, 16 Apr 2020 17:37:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25BC92223D for ; Thu, 16 Apr 2020 17:37:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587058647; bh=c6RjcLo9mHi0Qj+iI/ymrQ+8S7krFiwa/crVExYtMzc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=W1fit2gY3J6BbtGHLpo8vsbBY1vE4n0afTyxjm5lXSJDyNcA/sd0TzoxH9++jZGgk nYzXT1+JNVs6zlET92v8ekfbgxRGDIef0VKcoQWKszYJom0jRhT6fUTS4q3SgUA/Tu X3MQXHGKZofvh9otNyT7iAa2WLcw/nTICvqeg854= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730270AbgDPRhZ (ORCPT ); Thu, 16 Apr 2020 13:37:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:57854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729673AbgDPRhW (ORCPT ); Thu, 16 Apr 2020 13:37:22 -0400 Received: from Mani-XPS-13-9360 (unknown [157.50.106.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D183A2076D; Thu, 16 Apr 2020 17:37:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587058642; bh=c6RjcLo9mHi0Qj+iI/ymrQ+8S7krFiwa/crVExYtMzc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MPW/w2Hfnyk6tUbCwgA+epGBp7s9x8qUWJj1HiCBq+J9LTkOTM2QYZTP/j5uo/wrm Zu7E5RQleCiRVXkZUgTILmP6u9Q5+x1hOTZEgCwX8xxgd1Ay9ngjsrcfWax9ah1H31 eWIhS2p6dEJvzP9lw8E2V62BIIK92l1CFStWvCOY= Date: Thu, 16 Apr 2020 23:07:10 +0530 From: Manivannan Sadhasivam To: Andy Shevchenko Cc: Greg Kroah-Hartman , Rob Herring , Maxime Coquelin , Alexandre TORGUE , "open list:SERIAL DRIVERS" , devicetree , linux-stm32@st-md-mailman.stormreply.com, linux-arm Mailing List , Linux Kernel Mailing List Subject: Re: [PATCH 0/2] Add software flow control support for STM32 UART Message-ID: <20200416173710.GA4548@Mani-XPS-13-9360> References: <20200412180923.30774-1-mani@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andy, On Mon, Apr 13, 2020 at 12:17:21PM +0300, Andy Shevchenko wrote: > On Mon, Apr 13, 2020 at 7:06 AM wrote: > > > > From: Manivannan Sadhasivam > > > > Hello, > > > > This patchset adds software flow control support for STM32 UART controller. > > This is necessary for the upcoming STM32MP1 based board called Stinger96 > > IoT-Box. On that board, a bluetooth chip is connected to one of the UART > > controller but the CTS/RTS lines got swapped mistakenly. So in order to > > workaround that hardware bug and also to support the usecase of using only > > Tx/Rx pins, this patchset adds software flow control support. > > > > This patchset has been validated w/ Stinger96 IoT-Box connected to Murata > > WiFi-BT combo chip. > > > > I think it's a mix of terminology or so. Looking into the patches I > found that it's required to have GPIOs for SW flow control. > No, SW flow control does not require any additional signals, except RxD/TxD. > Yikes. Yes I got it wrong. 'st,hw-flow-ctrl' property confused me :) > On top of that, it seems you adding mctrl-gpio functionality. Why > can't you use that one? And thus no bindings needs to be updated. > Sure. This looks feasible. Will submit a follow up patch. Thanks, Mani > > Thanks, > > Mani > > > > Manivannan Sadhasivam (2): > > dt-bindings: serial: Add binding for software flow control in STM32 > > UART > > tty: serial: Add software flow control support for STM32 USART > > > > .../bindings/serial/st,stm32-uart.yaml | 15 +- > > drivers/tty/serial/stm32-usart.c | 143 +++++++++++++++++- > > drivers/tty/serial/stm32-usart.h | 4 + > > 3 files changed, 155 insertions(+), 7 deletions(-) > > > > -- > > 2.17.1 > > > > > -- > With Best Regards, > Andy Shevchenko