USB: ftdi_sio.c: Use ftdi async_icount structure for TIOCMIWAIT, as in other drivers
Uwe Bonnes [Mon, 10 Oct 2011 15:24:51 +0000 (17:24 +0200)]
Signed-off-by: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/ftdi_sio.c

index 9699580..8fe034d 100644 (file)
@@ -2328,6 +2328,8 @@ static int ftdi_ioctl(struct tty_struct *tty,
 {
        struct usb_serial_port *port = tty->driver_data;
        struct ftdi_private *priv = usb_get_serial_port_data(port);
+       struct async_icount cnow;
+       struct async_icount cprev;
 
        dbg("%s cmd 0x%04x", __func__, cmd);
 
@@ -2347,41 +2349,30 @@ static int ftdi_ioctl(struct tty_struct *tty,
         * - mask passed in arg for lines of interest
         *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
         * Caller should use TIOCGICOUNT to see which one it was.
-        * (except that the driver doesn't support it !)
         *
         * This code is borrowed from linux/drivers/char/serial.c
         */
        case TIOCMIWAIT:
-               while (priv != NULL) {
+               cprev = priv->icount;
+               while (1) {
                        interruptible_sleep_on(&priv->delta_msr_wait);
                        /* see if a signal did it */
                        if (signal_pending(current))
                                return -ERESTARTSYS;
-                       else {
-                               char diff = priv->diff_status;
-
-                               if (diff == 0)
-                                       return -EIO; /* no change => error */
-
-                               /* Consume all events */
-                               priv->diff_status = 0;
-
-                               /* Return 0 if caller wanted to know about
-                                  these bits */
-                               if (((arg & TIOCM_RNG) && (diff & FTDI_RS0_RI)) ||
-                                   ((arg & TIOCM_DSR) && (diff & FTDI_RS0_DSR)) ||
-                                   ((arg & TIOCM_CD)  && (diff & FTDI_RS0_RLSD)) ||
-                                   ((arg & TIOCM_CTS) && (diff & FTDI_RS0_CTS))) {
-                                       return 0;
-                               }
-                               /*
-                                * Otherwise caller can't care less about what
-                                * happened,and so we continue to wait for more
-                                * events.
-                                */
+                       cnow = priv->icount;
+                       if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
+                           cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
+                               return -EIO; /* no change => error */
+                       if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
+                           ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
+                           ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
+                           ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
+                               return 0;
                        }
+                       cprev = cnow;
                }
-               return 0;
+               /* not reached */
+               break;
        case TIOCSERGETLSR:
                return get_lsr_info(port, (struct serial_struct __user *)arg);
                break;