USB: spcp8x5: add proper modem-status support

Fetch modem status on carrier_raised and tiocmget.

This driver appeared to support modem-status but only read the modem
status registers once at open and then used that cached value for all
further enquires.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/spcp8x5.c b/drivers/usb/serial/spcp8x5.c
index a454a3f1acb3c01c907b650726ae6c71fca8d409..cf3df793c2b7a1a7781e908e0a5d2385e7056f5b 100644 (file)
--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -1,7 +1,7 @@
 /*
  * spcp8x5 USB to serial adaptor driver
  *
- * Copyright (C) 2010 Johan Hovold (jhovold@gmail.com)
+ * Copyright (C) 2010-2013 Johan Hovold (jhovold@gmail.com)
  * Copyright (C) 2006 Linxb (xubin.lin@worldplus.com.cn)
  * Copyright (C) 2006 S1 Corp.
  *
@@ -145,7 +145,6 @@ struct spcp8x5_private {
        unsigned                quirks;
        spinlock_t              lock;
        u8                      line_control;
-       u8                      line_status;
 };
 
 static int spcp8x5_probe(struct usb_serial *serial,
@@ -249,9 +248,11 @@ static void spcp8x5_set_work_mode(struct usb_serial_port *port, u16 value,
 
 static int spcp8x5_carrier_raised(struct usb_serial_port *port)
 {
-       struct spcp8x5_private *priv = usb_get_serial_port_data(port);
+       u8 msr;
+       int ret;
 
-       if (priv->line_status & MSR_STATUS_LINE_DCD)
+       ret = spcp8x5_get_msr(port, &msr);
+       if (ret || msr & MSR_STATUS_LINE_DCD)
                return 1;
 
        return 0;
@@ -397,9 +398,6 @@ static int spcp8x5_open(struct tty_struct *tty, struct usb_serial_port *port)
        struct usb_serial *serial = port->serial;
        struct spcp8x5_private *priv = usb_get_serial_port_data(port);
        int ret;
-       unsigned long flags;
-       u8 status = 0x30;
-       /* status 0x30 means DSR and CTS = 1 other CDC RI and delta = 0 */
 
        usb_clear_halt(serial->dev, port->write_urb->pipe);
        usb_clear_halt(serial->dev, port->read_urb->pipe);
@@ -412,17 +410,9 @@ static int spcp8x5_open(struct tty_struct *tty, struct usb_serial_port *port)
 
        spcp8x5_set_ctrl_line(port, priv->line_control);
 
-       /* Setup termios */
        if (tty)
                spcp8x5_set_termios(tty, port, &tmp_termios);
 
-       spcp8x5_get_msr(port, &status);
-
-       /* may be we should update uart status here but now we did not do */
-       spin_lock_irqsave(&priv->lock, flags);
-       priv->line_status = status & 0xf0 ;
-       spin_unlock_irqrestore(&priv->lock, flags);
-
        port->port.drain_delay = 256;
 
        return usb_serial_generic_open(tty, port);
@@ -457,12 +447,15 @@ static int spcp8x5_tiocmget(struct tty_struct *tty)
        struct spcp8x5_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        unsigned int mcr;
-       unsigned int status;
+       u8 status;
        unsigned int result;
 
+       result = spcp8x5_get_msr(port, &status);
+       if (result)
+               return result;
+
        spin_lock_irqsave(&priv->lock, flags);
        mcr = priv->line_control;
-       status = priv->line_status;
        spin_unlock_irqrestore(&priv->lock, flags);
 
        result = ((mcr & MCR_DTR)                       ? TIOCM_DTR : 0)