From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Richard Genoud <richard.genoud@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Nicolas Ferre <nicolas.ferre@atmel.com>,
linux-kernel@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@free-electrons.com>,
linux-serial@vger.kernel.org,
Cyrille Pitchen <cyrille.pitchen@atmel.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv2 2/3] tty/serial: at91: fix hardware handshake with GPIOs
Date: Thu, 22 Sep 2016 15:20:45 +0200 [thread overview]
Message-ID: <20160922132045.tbrd5u56qasaf7gn@pengutronix.de> (raw)
In-Reply-To: <20160912094733.21501-3-richard.genoud@gmail.com>
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 <richard.genoud@gmail.com>
> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> 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/ |
next prev parent reply other threads:[~2016-09-22 13:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-12 9:47 [PATCHv2 0/3] Fix handware handshake on SAM9x5 platforms Richard Genoud
2016-09-12 9:47 ` [PATCHv2 1/3] serial: mctrl_gpio: implement mctrl_gpio_use_rtscts Richard Genoud
2016-09-22 13:14 ` Uwe Kleine-König
2016-09-26 11:57 ` Richard Genoud
2016-09-12 9:47 ` [PATCHv2 2/3] tty/serial: at91: fix hardware handshake with GPIOs Richard Genoud
2016-09-22 9:47 ` Greg Kroah-Hartman
2016-09-22 13:20 ` Uwe Kleine-König [this message]
2016-09-27 7:45 ` Richard Genoud
2016-09-12 9:47 ` [PATCHv2 3/3] tty/serial: at91: fix hardware handshake on SAM9x5 (without GPIOs) Richard Genoud
2016-09-12 9:53 ` Alexandre Belloni
2016-09-12 10:50 ` Richard Genoud
2016-09-13 13:45 ` Alexandre Belloni
2016-09-14 10:31 ` Richard Genoud
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