From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752257AbeFAMkm (ORCPT ); Fri, 1 Jun 2018 08:40:42 -0400 Received: from mail.micronovasrl.com ([212.103.203.10]:38620 "EHLO mail.micronovasrl.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752128AbeFAMke (ORCPT ); Fri, 1 Jun 2018 08:40:34 -0400 Authentication-Results: mail.micronovasrl.com (amavisd-new); dkim=pass reason="pass (just generated, assumed good)" header.d=micronovasrl.com X-Spam-Flag: NO X-Spam-Score: -2.9 From: Giulio Benetti To: Greg Kroah-Hartman Cc: Jiri Slaby , Andy Shevchenko , Kees Cook , Matthias Brugger , Allen Pais , Sean Young , Ed Blake , Stefan Potyra , Philipp Zabel , Joshua Scott , Vignesh R , Rolf Evers-Fischer , Aaron Sierra , Rafael Gago , Joel Stanley , Sean Wang , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Giulio Benetti Subject: [PATCH 1/8] serial: 8250_dw: add em485 support Date: Fri, 1 Jun 2018 14:40:14 +0200 Message-Id: <20180601124021.102970-2-giulio.benetti@micronovasrl.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180601124021.102970-1-giulio.benetti@micronovasrl.com> References: <20180601124021.102970-1-giulio.benetti@micronovasrl.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Need to use rs485 transceiver so let's use existing em485 485 emulation layer on top of 8250. Add rs485_config callback to port. Signed-off-by: Giulio Benetti --- drivers/tty/serial/8250/8250_dw.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index 6fcdb90f616a..45366e6e5411 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -314,6 +314,36 @@ static void dw8250_set_ldisc(struct uart_port *p, struct ktermios *termios) serial8250_do_set_ldisc(p, termios); } +static int dw8250_rs485_config(struct uart_port *p, + struct serial_rs485 *rs485) +{ + struct uart_8250_port *up = up_to_u8250p(p); + + /* Clamp the delays to [0, 100ms] */ + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); + + p->rs485 = *rs485; + + /* + * Both serial8250_em485_init and serial8250_em485_destroy + * are idempotent + */ + if (rs485->flags & SER_RS485_ENABLED) { + int ret = serial8250_em485_init(up); + + if (ret) { + rs485->flags &= ~SER_RS485_ENABLED; + p->rs485.flags &= ~SER_RS485_ENABLED; + } + return ret; + } + + serial8250_em485_destroy(up); + + return 0; +} + /* * dw8250_fallback_dma_filter will prevent the UART from getting just any free * channel on platforms that have DMA engines, but don't have any channels @@ -449,6 +479,7 @@ static int dw8250_probe(struct platform_device *pdev) p->serial_out = dw8250_serial_out; p->set_ldisc = dw8250_set_ldisc; p->set_termios = dw8250_set_termios; + p->rs485_config = dw8250_rs485_config; p->membase = devm_ioremap(dev, regs->start, resource_size(regs)); if (!p->membase) -- 2.17.0