On 12/09/2016 at 12:50:38 +0200, Richard Genoud wrote :
> >> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> >> index e9b4fbf88c2d..32154e7231ce 100644
> >> --- a/drivers/tty/serial/atmel_serial.c
> >> +++ b/drivers/tty/serial/atmel_serial.c
> >> @@ -2130,15 +2130,19 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
> >> } else if ((termios->c_cflag & CRTSCTS) &&
> >> !mctrl_gpio_use_rtscts(atmel_port->gpios)) {
> >> /*
> >> - * RS232 with hardware handshake (RTS/CTS)
> >> - * handled by the controller.
> >> + * Automatic hardware handshake (RTS/CTS) only work with
> >> + * FIFOs or PDC.
> >> + * Meaning that on SAM9x5 the controller can't handle
> >> + * the hardware handshake (no FIFOs nor PDC on these platforms).
> >> */
> >> - 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;
> >> - } else {
> >> + if (atmel_use_pdc_rx(port) || atmel_use_fifo(port))
> >> mode |= ATMEL_US_USMODE_HWHS;
> >> - }
> >> + else
> >> + /*
> >> + * The hardware handshake won't be handle by the
> >> + * controller but by the driver.
> >> + */
> >> + mode |= ATMEL_US_USMODE_NORMAL;
> >
> > You still need the case where HWHS is impossible and there are no gpio
> > configured. You need to inform userspace that the configuration was not
> > applied instead of silently ignoring the error.
>
> Could you explain which case it is ?
> The only one I can see is when there's no GPIO declared for RTS/CTS
> AND, there's no pin muxed for RTS/CTS either.
>
> Have you got another example in mind ?
>
Hum, actually, it is that case. The other one (CRTSCTS and gpios) is
handled in the else below. I think you need to keep the termios->c_cflag
&= ~CRTSCTS; here so that userspace knows configuring it failed.
> >
> >> } else {
> >> /* RS232 without hadware handshake or controlled by GPIOs */
> >> mode |= ATMEL_US_USMODE_NORMAL;
> >
--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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