tty/serial: atmel: fix hardware handshake selection

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / drivers / tty / serial / atmel_serial.c

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 9429455..7bbadd1 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -277,6 +277,13 @@ static bool atmel_use_dma_rx(struct uart_port *port)
        return atmel_port->use_dma_rx;
 }
 
+static bool atmel_use_fifo(struct uart_port *port)
+{
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+       return atmel_port->fifo_size;
+}
+
 static unsigned int atmel_get_lines_status(struct uart_port *port)
 {
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
@@ -2169,7 +2176,12 @@ 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) */
-               mode |= ATMEL_US_USMODE_HWHS;
+               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 {
+                       mode |= ATMEL_US_USMODE_HWHS;
+               }
        } else {
                /* RS232 without hadware handshake */
                mode |= ATMEL_US_USMODE_NORMAL;