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 b462d0c548237fae605cfe63a689cc216f8f945e..c662eb36be2926e60d97c1cfd8489d0da839ba89 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 72bc1dbcd055bba2f2c50c83f891584c36a747c7..381a2d79593c3078b4255f1c97177b00f3f5fa39 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;