serial: imx: repair and complete handshaking

The .get_mctrl callback should not report the status of RTS or LOOP, so
drop this. Instead implement reporting the state of CAR (aka DCD) and
RI.

For .set_mctrl implement setting the DTR line.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 76818f53f0ae6bec8ccf0c2d315126efe4351ba8..086675e4ef73c83ad44fd97d2d4b6641b2b487e1 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -148,8 +148,11 @@
 #define USR2_TXFE       (1<<14) /* Transmit buffer FIFO empty */
 #define USR2_DTRF       (1<<13) /* DTR edge interrupt flag */
 #define USR2_IDLE       (1<<12) /* Idle condition */
+#define USR2_RIDELT     (1<<10) /* Ring Interrupt Delta */
+#define USR2_RIIN       (1<<9)  /* Ring Indicator Input */
 #define USR2_IRINT      (1<<8)  /* Serial infrared interrupt flag */
 #define USR2_WAKE       (1<<7)  /* Wake */
+#define USR2_DCDIN      (1<<5)  /* Data Carrier Detect Input */
 #define USR2_RTSF       (1<<4)  /* RTS edge interrupt flag */
 #define USR2_TXDC       (1<<3)  /* Transmitter complete */
 #define USR2_BRCD       (1<<2)  /* Break condition */
@@ -804,16 +807,19 @@ static unsigned int imx_tx_empty(struct uart_port *port)
 static unsigned int imx_get_mctrl(struct uart_port *port)
 {
        struct imx_port *sport = (struct imx_port *)port;
-       unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
+       unsigned int tmp = TIOCM_DSR;
+       unsigned usr1 = readl(sport->port.membase + USR1);
 
-       if (readl(sport->port.membase + USR1) & USR1_RTSS)
+       if (usr1 & USR1_RTSS)
                tmp |= TIOCM_CTS;
 
-       if (readl(sport->port.membase + UCR2) & UCR2_CTS)
-               tmp |= TIOCM_RTS;
+       /* in DCE mode DCDIN is always 0 */
+       if (!(usr1 & USR2_DCDIN))
+               tmp |= TIOCM_CAR;
 
-       if (readl(sport->port.membase + uts_reg(sport)) & UTS_LOOP)
-               tmp |= TIOCM_LOOP;
+       /* in DCE mode RIIN is always 0 */
+       if (readl(sport->port.membase + USR2) & USR2_RIIN)
+               tmp |= TIOCM_RI;
 
        return tmp;
 }
@@ -831,6 +837,11 @@ static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
                writel(temp, sport->port.membase + UCR2);
        }
 
+       temp = readl(sport->port.membase + UCR3) & ~UCR3_DSR;
+       if (!(mctrl & TIOCM_DTR))
+               temp |= UCR3_DSR;
+       writel(temp, sport->port.membase + UCR3);
+
        temp = readl(sport->port.membase + uts_reg(sport)) & ~UTS_LOOP;
        if (mctrl & TIOCM_LOOP)
                temp |= UTS_LOOP;