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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 71567C433E9 for ; Thu, 14 Jan 2021 12:34:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35B8B23A55 for ; Thu, 14 Jan 2021 12:34:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727875AbhANMeb (ORCPT ); Thu, 14 Jan 2021 07:34:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:56458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726076AbhANMea (ORCPT ); Thu, 14 Jan 2021 07:34:30 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C769A23A52; Thu, 14 Jan 2021 12:33:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610627629; bh=C5d5NyVY11M+UZtH0nRm7QFZahShBi0foysS5SgWurk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ntt/oKDDraSkmoJx427OZLk1rpsEgDsIYtKkYX8xv47b5WhU0EpX3alAYx+7krXbM Ql/KqTKpFmkCXri0l2ibe+Ol7s8dgR7p+TkMJLc81nd+4qU9Tc68qPPu/ecn2JcMp8 rSzJfsSbHEOW8MTmZa/oPxWV96s/5qCSeiRyd+eo= Date: Thu, 14 Jan 2021 13:33:46 +0100 From: Greg KH To: zhangqiumiao1@huawei.com Cc: jirislaby@kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org Subject: Re: [PATCH v3] tty: make pl011 serial port driver support 485 mode Message-ID: References: <1610627310-28889-1-git-send-email-zhangqiumiao1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1610627310-28889-1-git-send-email-zhangqiumiao1@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 14, 2021 at 08:28:30PM +0800, zhangqiumiao1@huawei.com wrote: > From: Qiumiao Zhang > > make pl011 serial port support 485 mode full duplex communication > > Signed-off-by: Qiumiao Zhang > --- > Changes in v3: > -Fix busy loop forever in pl011_tx_empty > -Move the definition of cr into uart_amba_port > -run checkpatch with no error or warning > > Changes in v2: > -Fix two compilation errors > > drivers/tty/serial/amba-pl011.c | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index c255476..9da10a4 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c > @@ -44,6 +44,7 @@ > > #include "amba-pl011.h" > > +#define ISEMPTY 1 > #define UART_NR 14 > > #define SERIAL_AMBA_MAJOR 204 > @@ -264,6 +265,7 @@ struct uart_amba_port { > unsigned int fifosize; /* vendor-specific */ > unsigned int old_cr; /* state during shutdown */ > unsigned int fixed_baud; /* vendor-set fixed baud rate */ > + unsigned int cr; > char type[12]; > #ifdef CONFIG_DMA_ENGINE > /* DMA stuff */ > @@ -1284,6 +1286,8 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) > #define pl011_dma_flush_buffer NULL > #endif > > +static unsigned int pl011_tx_empty(struct uart_port *port); > + > static void pl011_stop_tx(struct uart_port *port) > { > struct uart_amba_port *uap = > @@ -1292,6 +1296,17 @@ static void pl011_stop_tx(struct uart_port *port) > uap->im &= ~UART011_TXIM; > pl011_write(uap->im, uap, REG_IMSC); > pl011_dma_tx_stop(uap); > + if (port->rs485.flags & SER_RS485_ENABLED) { > + while(pl011_tx_empty(port) != ISEMPTY) ; No busy loops that run forever please. > + > + uap->cr = pl011_read(uap, REG_CR); > + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) { > + uap->cr |= UART011_CR_RTS; > + } else { > + uap->cr &= ~UART011_CR_RTS; > + } checkpatch did not complain about this? It should have. thanks, greg k-h