From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933846AbcIVNVT (ORCPT ); Thu, 22 Sep 2016 09:21:19 -0400 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:53160 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933337AbcIVNVQ (ORCPT ); Thu, 22 Sep 2016 09:21:16 -0400 Date: Thu, 22 Sep 2016 15:20:45 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Richard Genoud Cc: Cyrille Pitchen , Alexandre Belloni , Nicolas Ferre , Greg Kroah-Hartman , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHv2 2/3] tty/serial: at91: fix hardware handshake with GPIOs Message-ID: <20160922132045.tbrd5u56qasaf7gn@pengutronix.de> References: <20160912094733.21501-1-richard.genoud@gmail.com> <20160912094733.21501-3-richard.genoud@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160912094733.21501-3-richard.genoud@gmail.com> User-Agent: Mutt/1.6.2-neo (2016-06-11) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 12, 2016 at 11:47:32AM +0200, Richard Genoud wrote: > Commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when > hardware handshake is enabled") broke the hardware handshake when GPIOs > where used. s/where/were/ > Hardware handshake with GPIOs used to work before this commit because > the CRTSCTS flag (termios->c_cflag) was set, but not the > ATMEL_US_USMODE_HWHS flag (controller register) ; so hardware handshake > enabled, but not handled by the controller. > > This commit restores this behaviour. > > NB: -stable is not Cced because it doesn't cleanly apply on 4.1+ > and it will also need previous commit: > "serial: mctrl_gpio: implement mctrl_gpio_use_rtscts" > > Signed-off-by: Richard Genoud > Acked-by: Alexandre Belloni > Fixes: 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled") > --- > drivers/tty/serial/atmel_serial.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c > index 2eaa18ddef61..e9b4fbf88c2d 100644 > --- a/drivers/tty/serial/atmel_serial.c > +++ b/drivers/tty/serial/atmel_serial.c > @@ -2025,6 +2025,7 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state, > static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, > struct ktermios *old) > { > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > unsigned long flags; > unsigned int old_mode, mode, imr, quot, baud; > > @@ -2126,8 +2127,12 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, > atmel_uart_writel(port, ATMEL_US_TTGR, > port->rs485.delay_rts_after_send); > mode |= ATMEL_US_USMODE_RS485; > - } else if (termios->c_cflag & CRTSCTS) { > - /* RS232 with hardware handshake (RTS/CTS) */ > + } else if ((termios->c_cflag & CRTSCTS) && > + !mctrl_gpio_use_rtscts(atmel_port->gpios)) { IMHO the behaviour of the hw controlled pins shouldn't change when mctrl_gpio is in use (if possible). But I don't understand the issue so I guess you need a better changelog. > + /* > + * RS232 with hardware handshake (RTS/CTS) > + * handled by the controller. > + */ > if (atmel_use_dma_rx(port) && !atmel_use_fifo(port)) { > dev_info(port->dev, "not enabling hardware flow control because DMA is used"); > termios->c_cflag &= ~CRTSCTS; > @@ -2135,7 +2140,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, > mode |= ATMEL_US_USMODE_HWHS; > } > } else { > - /* RS232 without hadware handshake */ > + /* RS232 without hadware handshake or controlled by GPIOs */ When touching this line, please also do s/hadware/hardware/. > mode |= ATMEL_US_USMODE_NORMAL; > } Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |