From 6a171b29937984a5e0bf29d6577b055998f03edb Mon Sep 17 00:00:00 2001 From: Jason Uy Date: Wed, 11 Jan 2017 11:48:20 -0800 Subject: [PATCH] serial: 8250_dw: Allow hardware flow control to be used 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 Reviewed-by: Ray Jui Signed-off-by: Jason Uy Reviewed-by: Kefeng Wang Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- 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 c89fafc..c89ae45 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -248,11 +248,11 @@ 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); } @@ -326,13 +326,11 @@ 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; @@ -414,6 +412,7 @@ static int dw8250_probe(struct platform_device *pdev) p->serial_in = dw8250_serial_in; p->serial_out = dw8250_serial_out; p->set_ldisc = dw8250_set_ldisc; + p->set_termios = dw8250_set_termios; p->membase = devm_ioremap(dev, regs->start, resource_size(regs)); if (!p->membase) -- 2.7.4