| Message ID | 20160907161324.27774-2-richard.genoud@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07/09/2016 at 18:13:23 +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. > > 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> > Fixes: 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled") Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> > --- > 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)) { > + /* > + * 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 */ > mode |= ATMEL_US_USMODE_NORMAL; > } >
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)) { + /* + * 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 */ mode |= ATMEL_US_USMODE_NORMAL; }
Commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled") broke the hardware handshake when GPIOs where used. 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> 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(-)