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 6A70BC433EF for ; Wed, 2 Mar 2022 09:57:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240793AbiCBJ54 (ORCPT ); Wed, 2 Mar 2022 04:57:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240748AbiCBJ5o (ORCPT ); Wed, 2 Mar 2022 04:57:44 -0500 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE12E97B96; Wed, 2 Mar 2022 01:57:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646215021; x=1677751021; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mG40HTqpEgp/9V7rBkq1TB4ShO4U7Y47+Ht/i8vsZY8=; b=U21VTUMscXCB+irCii/TWrWjAHl/6s//6TalBV8KojC8h4ZYJn6PzcWA dnnLtMuSIKcQRVuLJesrB1JNxwpG6ogMclD2Dpq/8WHigxs02QJbUmkuJ N3DxWyKZOU8nRydhN1mwnpA5K+quhfNh5//8ZHLzUDVFhalP2f8MuDLzs Bi/5Y/HMyO6i2VFiXQJHZecWr3TxsjQOdJIS5WAw1USxvyvWbZfqZ/mbr PljetaVwX+FHLMafbzH9DNDoiSqIH06790FnjYDoh2Cm/mSnBZPysxeQq dL3rVjH2Wjj7sto/PjPlC8xUg6QCC7kEhtTVI0MZtcURMZ9eek69MCZ52 g==; X-IronPort-AV: E=McAfee;i="6200,9189,10273"; a="233980139" X-IronPort-AV: E=Sophos;i="5.90,148,1643702400"; d="scan'208";a="233980139" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2022 01:57:01 -0800 X-IronPort-AV: E=Sophos;i="5.90,148,1643702400"; d="scan'208";a="551182079" Received: from abotoi-mobl2.ger.corp.intel.com (HELO ijarvine-MOBL2.ger.corp.intel.com) ([10.251.218.48]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2022 01:56:58 -0800 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= To: linux-serial@vger.kernel.org, Jiri Slaby , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Lukas Wunner , Johan Hovold , Andy Shevchenko , Heikki Krogerus , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Raymond Tan Subject: [PATCH 2/7] serial: 8250_dwlib: RS485 HW full duplex support Date: Wed, 2 Mar 2022 11:56:01 +0200 Message-Id: <20220302095606.14818-3-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220302095606.14818-1-ilpo.jarvinen@linux.intel.com> References: <20220302095606.14818-1-ilpo.jarvinen@linux.intel.com> 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 The Synopsys DesignWare UART has a build-in support for the RS485 protocol from IP version 4.0 onward. This patch enables the support of HW Full Duplex mode support for it. To ask for full duplex mode, userspace sets SER_RS485_RX_DURING_TX flag and HW will take care of the rest. Co-developed-by: Raymond Tan Signed-off-by: Raymond Tan Signed-off-by: Ilpo Järvinen --- drivers/tty/serial/8250/8250_dwlib.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c index a4f09a95049b..d26792999984 100644 --- a/drivers/tty/serial/8250/8250_dwlib.c +++ b/drivers/tty/serial/8250/8250_dwlib.c @@ -110,9 +110,14 @@ static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485) if (rs485->flags & SER_RS485_ENABLED) { /* Clearing unsupported flags. */ - rs485->flags &= SER_RS485_ENABLED; - - tcr |= DW_UART_TCR_RS485_EN | DW_UART_TCR_XFER_MODE_DE_OR_RE; + rs485->flags &= SER_RS485_ENABLED | SER_RS485_RX_DURING_TX; + tcr |= DW_UART_TCR_RS485_EN; + + if (rs485->flags & SER_RS485_RX_DURING_TX) { + tcr |= DW_UART_TCR_XFER_MODE_DE_DURING_RE; + } else { + tcr |= DW_UART_TCR_XFER_MODE_DE_OR_RE; + } dw8250_writel_ext(p, DW_UART_DE_EN, 1); dw8250_writel_ext(p, DW_UART_RE_EN, 1); } else { -- 2.30.2