From patchwork Mon Jun 1 05:21:07 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bhuvanchandra DV X-Patchwork-Id: 6517341 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A16FCC0020 for ; Mon, 1 Jun 2015 05:24:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C099C205C6 for ; Mon, 1 Jun 2015 05:24:36 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E19BD205BB for ; Mon, 1 Jun 2015 05:24:35 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YzIBZ-0003E8-Vq; Mon, 01 Jun 2015 05:22:53 +0000 Received: from mail-db3on0148.outbound.protection.outlook.com ([157.55.234.148] helo=emea01-db3-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YzIAp-0002w8-ED for linux-arm-kernel@lists.infradead.org; Mon, 01 Jun 2015 05:22:08 +0000 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=bhuvanchandra.dv@toradex.com; Received: from tdx.toradex.int (115.115.225.206) by DB3PR05MB267.eurprd05.prod.outlook.com (10.141.4.26) with Microsoft SMTP Server (TLS) id 15.1.172.22; Mon, 1 Jun 2015 05:21:53 +0000 From: Bhuvanchandra DV To: Subject: [PATCH V2 3/3] tty: serial: fsl_lpuart: Add support for RS-485 Date: Mon, 1 Jun 2015 10:51:07 +0530 Message-ID: <1433136067-20644-4-git-send-email-bhuvanchandra.dv@toradex.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1433136067-20644-1-git-send-email-bhuvanchandra.dv@toradex.com> References: <1433136067-20644-1-git-send-email-bhuvanchandra.dv@toradex.com> MIME-Version: 1.0 X-Originating-IP: [115.115.225.206] X-ClientProxiedBy: HK2PR0201CA0018.apcprd02.prod.outlook.com (25.162.206.28) To DB3PR05MB267.eurprd05.prod.outlook.com (10.141.4.26) X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:DB3PR05MB267; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0; PCL:0; RULEID:(601004)(520003)(5005006)(3002001); SRVR:DB3PR05MB267; BCL:0; PCL:0; RULEID:; SRVR:DB3PR05MB267; X-Forefront-PRVS: 05947791E4 X-Forefront-Antispam-Report: SFV:NSPM; SFS:(10019020)(6009001)(189002)(199003)(77096005)(50226001)(5001960100002)(2950100001)(77156002)(68736005)(46102003)(189998001)(92566002)(50466002)(50986999)(86362001)(62966003)(66066001)(48376002)(87976001)(105586002)(53416004)(229853001)(2351001)(107886002)(69596002)(19580395003)(5001830100001)(5001920100001)(5001860100001)(101416001)(19580405001)(81156007)(42186005)(110136002)(36756003)(47776003)(64706001)(106356001)(33646002)(4001540100001)(76176999)(40100003)(97736004)(122386002)(4001430100001); DIR:OUT; SFP:1102; SCL:1; SRVR:DB3PR05MB267; H:tdx.toradex.int; FPR:; SPF:None; PTR:InfoNoRecords; MX:1; A:1; LANG:en; Received-SPF: None (protection.outlook.com: toradex.com does not designate permitted sender hosts) X-OriginatorOrg: toradex.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Jun 2015 05:21:53.1843 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB3PR05MB267 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150531_222207_689936_269083ED X-CRM114-Status: GOOD ( 12.77 ) X-Spam-Score: -1.1 (-) Cc: devicetree@vger.kernel.org, linux-serial@vger.kernel.org, moorray3@wp.pl, linux-kernel@vger.kernel.org, stefan@agner.ch, bhuvanchandra.dv@gmail.com, kernel@pengutronix.de, shawn.guo@linaro.org, jslaby@suse.cz, linux-arm-kernel@lists.infradead.org, Bhuvanchandra DV X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Enable Vybrid's build-in support for RS-485 auto RTS for controlling line direction of RS-485 transceiver driver. Signed-off-by: Bhuvanchandra DV --- drivers/tty/serial/fsl_lpuart.c | 56 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 532cfb7..7b4e04a 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -820,6 +820,49 @@ static unsigned int lpuart32_tx_empty(struct uart_port *port) TIOCSER_TEMT : 0; } +static int lpuart_config_rs485(struct uart_port *port, + struct serial_rs485 *rs485) +{ + struct lpuart_port *sport = container_of(port, + struct lpuart_port, port); + u8 modem = readb(sport->port.membase + UARTMODEM) & + ~(UARTMODEM_TXRTSPOL | UARTMODEM_TXRTSE); + + writeb(modem, sport->port.membase + UARTMODEM); + + if (rs485->flags & SER_RS485_ENABLED) { + /* Enable auto RS-485 RTS mode */ + modem |= UARTMODEM_TXRTSE; + + /* + * RTS needs to be logic HIGH either during transer _or_ after + * transfer, other variants are not supported by the hardware. + */ + if (!(rs485->flags & (SER_RS485_RTS_ON_SEND | + SER_RS485_RTS_AFTER_SEND))) + rs485->flags |= SER_RS485_RTS_ON_SEND; + + if (rs485->flags & SER_RS485_RTS_ON_SEND && rs485->flags & + SER_RS485_RTS_AFTER_SEND) + rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; + + /* + * The hardware defaults to RTS logic HIGH while transfer. + * Switch polarity in case RTS shall be logic HIGH + * after transfer. + * Note: UART is assumed to be active high. + */ + if (rs485->flags & SER_RS485_RTS_AFTER_SEND) + modem |= UARTMODEM_TXRTSPOL; + } + + /* Store the new configuration */ + sport->port.rs485 = *rs485; + + writeb(modem, sport->port.membase + UARTMODEM); + return 0; +} + static unsigned int lpuart_get_mctrl(struct uart_port *port) { return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR; @@ -1191,6 +1234,12 @@ lpuart_set_termios(struct uart_port *port, struct ktermios *termios, cr1 |= UARTCR1_M; } + /* When auto RS-485 RTS mode is enabled, + * hardware flow control need to be disabled. + */ + if (sport->port.rs485.flags & SER_RS485_ENABLED) + termios->c_cflag &= ~CRTSCTS; + if (termios->c_cflag & CRTSCTS) { modem |= (UARTMODEM_RXRTSE | UARTMODEM_TXCTSE); } else { @@ -1749,6 +1798,8 @@ static int lpuart_probe(struct platform_device *pdev) sport->port.ops = &lpuart_pops; sport->port.flags = UPF_BOOT_AUTOCONF; + sport->port.rs485_config = lpuart_config_rs485; + sport->clk = devm_clk_get(&pdev->dev, "ipg"); if (IS_ERR(sport->clk)) { ret = PTR_ERR(sport->clk); @@ -1789,6 +1840,11 @@ static int lpuart_probe(struct platform_device *pdev) dev_info(sport->port.dev, "DMA rx channel request failed, " "operating without rx DMA\n"); + if (of_property_read_bool(np, "linux,rs485-enabled-at-boot-time")) { + sport->port.rs485.flags |= SER_RS485_ENABLED; + sport->port.rs485.flags |= SER_RS485_RTS_ON_SEND; + writeb(UARTMODEM_TXRTSE, sport->port.membase + UARTMODEM); + return 0; }