From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754581AbbE2IVL (ORCPT ); Fri, 29 May 2015 04:21:11 -0400 Received: from mail-db3on0115.outbound.protection.outlook.com ([157.55.234.115]:5120 "EHLO emea01-db3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752030AbbE2IVB (ORCPT ); Fri, 29 May 2015 04:21:01 -0400 X-Greylist: delayed 848 seconds by postgrey-1.27 at vger.kernel.org; Fri, 29 May 2015 04:21:00 EDT Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=bhuvanchandra.dv@toradex.com; From: Bhuvanchandra DV To: CC: , , , , , , , , , Bhuvanchandra DV Subject: [PATCH 3/3] tty: serial: fsl_lpuart: Add support for RS-485 Date: Fri, 29 May 2015 13:35:54 +0530 Message-ID: <1432886754-30115-4-git-send-email-bhuvanchandra.dv@toradex.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1432886754-30115-1-git-send-email-bhuvanchandra.dv@toradex.com> References: <1432886754-30115-1-git-send-email-bhuvanchandra.dv@toradex.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [115.115.225.206] X-ClientProxiedBy: HKNPR06CA0028.apcprd06.prod.outlook.com (10.141.16.18) To AM3PR05MB258.eurprd05.prod.outlook.com (10.242.249.24) X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:AM3PR05MB258;UriScan:;BCL:0;PCL:0;RULEID:;SRVR:AM3PR05MB0920; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(5005006)(520003)(3002001);SRVR:AM3PR05MB258;BCL:0;PCL:0;RULEID:;SRVR:AM3PR05MB258; X-Forefront-PRVS: 059185FE08 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10019020)(6009001)(189002)(199003)(69596002)(2351001)(86362001)(77096005)(101416001)(53416004)(19580395003)(92566002)(50466002)(68736005)(42186005)(5001830100001)(47776003)(5001860100001)(33646002)(110136002)(46102003)(106356001)(77156002)(105586002)(229853001)(66066001)(62966003)(189998001)(50226001)(40100003)(81156007)(64706001)(48376002)(50986999)(87976001)(76176999)(2950100001)(97736004)(122386002)(4001540100001)(107886002)(5001960100002)(19580405001)(36756003)(4001430100001);DIR:OUT;SFP:1102;SCL:1;SRVR:AM3PR05MB258;H:tdx.toradex.int;FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 May 2015 08:06:44.6976 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM3PR05MB258 X-OriginatorOrg: toradex.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 | 60 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 357f623..c553b14 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -820,6 +820,50 @@ 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_ON_SEND) + modem &= ~UARTMODEM_TXRTSPOL; + else 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; @@ -1204,6 +1248,12 @@ 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 { @@ -1762,6 +1812,8 @@ 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); @@ -1802,6 +1854,14 @@ 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); + } else { + sport->port.rs485.flags &= ~SER_RS485_ENABLED; + } + return 0; } -- 2.1.0