serial: imx: add support for DTE mode

The uart works in the DCE mode by default, but sometime we need it
works at the DTE mode.

This patch adds the support for the DTE mode.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
index b462d0c..c662eb3 100644 (file)
--- a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
+++ b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
@@ -8,6 +8,8 @@ Required properties:
 Optional properties:
 - fsl,uart-has-rtscts : Indicate the uart has rts and cts
 - fsl,irda-mode : Indicate the uart supports irda mode
+- fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
+                  is DCE mode by default.
 
 Example:
 
@@ -16,4 +18,5 @@ serial@73fbc000 {
        reg = <0x73fbc000 0x4000>;
        interrupts = <31>;
        fsl,uart-has-rtscts;
+       fsl,dte-mode;
 };

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 72bc1db..381a2d7 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -201,6 +201,7 @@ struct imx_port {
        unsigned int            old_status;
        int                     txirq, rxirq, rtsirq;
        unsigned int            have_rtscts:1;
+       unsigned int            dte_mode:1;
        unsigned int            use_irda:1;
        unsigned int            irda_inv_rx:1;
        unsigned int            irda_inv_tx:1;
@@ -1020,6 +1021,8 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
 
        ufcr = readl(sport->port.membase + UFCR);
        ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
+       if (sport->dte_mode)
+               ufcr |= UFCR_DCEDTE;
        writel(ufcr, sport->port.membase + UFCR);
 
        writel(num, sport->port.membase + UBIR);
@@ -1444,6 +1447,9 @@ static int serial_imx_probe_dt(struct imx_port *sport,
        if (of_get_property(np, "fsl,irda-mode", NULL))
                sport->use_irda = 1;
 
+       if (of_get_property(np, "fsl,dte-mode", NULL))
+               sport->dte_mode = 1;
+
        sport->devdata = of_id->data;
 
        return 0;