diff options
Diffstat (limited to 'drivers/tty/serial/atmel_serial.c')
| -rw-r--r-- | drivers/tty/serial/atmel_serial.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index fd8aa1f4ba78..168b10cad47b 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -2132,11 +2132,29 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, mode |= ATMEL_US_USMODE_RS485; } else if (termios->c_cflag & CRTSCTS) { /* RS232 with hardware handshake (RTS/CTS) */ - 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_fifo(port) && + !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) { + /* + * with ATMEL_US_USMODE_HWHS set, the controller will + * be able to drive the RTS pin high/low when the RX + * FIFO is above RXFTHRES/below RXFTHRES2. + * It will also disable the transmitter when the CTS + * pin is high. + * This mode is not activated if CTS pin is a GPIO + * because in this case, the transmitter is always + * disabled (there must be an internal pull-up + * responsible for this behaviour). + * If the RTS pin is a GPIO, the controller won't be + * able to drive it according to the FIFO thresholds, + * but it will be handled by the driver. + */ mode |= ATMEL_US_USMODE_HWHS; + } else { + /* + * For platforms without FIFO, the flow control is + * handled by the driver. + */ + mode |= ATMEL_US_USMODE_NORMAL; } } else { /* RS232 without hadware handshake */ |