[PATCH v1 1/1] serial: 8250_dw: Allow hardware flow control to be used

[Jason Uy]

In the most common use case, the Synopsys DW UART driver does not
set the set_termios callback function.  This prevents UPSTAT_AUTOCTS
from being set when the UART flag CRTSCTS is set.  As a result, the
driver will use software flow control as opposed to hardware flow
control.

To fix the problem, the set_termios callback function is set to the
DW specific function.  The logic to set UPSTAT_AUTOCTS is moved so
that any clock error will not affect setting the hardware flow
control.

Reviewed-by: Scott Branden <scott.bran...@broadcom.com>
Reviewed-by: Ray Jui <ray....@broadcom.com>
Signed-off-by: Jason Uy <jason...@broadcom.com>
---
 drivers/tty/serial/8250/8250_dw.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c 
b/drivers/tty/serial/8250/8250_dw.c
index 459d726..18f1f8b 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -246,11 +246,11 @@ static void dw8250_set_termios(struct uart_port *p, 
struct ktermios *termios,
        if (!ret)
                p->uartclk = rate;
 
+out:
        p->status &= ~UPSTAT_AUTOCTS;
        if (termios->c_cflag & CRTSCTS)
                p->status |= UPSTAT_AUTOCTS;
 
-out:
        serial8250_do_set_termios(p, termios, old);
 }
 
@@ -308,13 +308,11 @@ static void dw8250_quirks(struct uart_port *p, struct 
dw8250_data *data)
                        p->serial_in = dw8250_serial_in32;
                        data->uart_16550_compatible = true;
                }
-               p->set_termios = dw8250_set_termios;
        }
 
        /* Platforms with iDMA */
        if (platform_get_resource_byname(to_platform_device(p->dev),
                                         IORESOURCE_MEM, "lpss_priv")) {
-               p->set_termios = dw8250_set_termios;
                data->dma.rx_param = p->dev->parent;
                data->dma.tx_param = p->dev->parent;
                data->dma.fn = dw8250_idma_filter;
@@ -392,6 +390,7 @@ static int dw8250_probe(struct platform_device *pdev)
        p->iotype       = UPIO_MEM;
        p->serial_in    = dw8250_serial_in;
        p->serial_out   = dw8250_serial_out;
+       p->set_termios  = dw8250_set_termios;
 
        p->membase = devm_ioremap(dev, regs->start, resource_size(regs));
        if (!p->membase)
-- 
1.9.1