[PATCH 5.10 41/43] USB: serial: spcp8x5: drop broken carrier detect support

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit d37186bd95a07e334447f47274a38a311dad2172 upstream.

The driver does not support modem status notifications and instead used
to fetch the modem status once at open() and subsequently operate on and
report stale state.

As part of fixing this, a call to fetch the status was added to
carrier_raised(), which does not work as that callback must not sleep
(e.g. unlike tiocmget()).

Drop the broken carrier detect support.

Fixes: e1ed212d8593 ("USB: spcp8x5: add proper modem-status support")
Cc: stable@vger.kernel.org	# 3.10
Reported-by: syzbot+3b514b87202742f22c44@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/6a73cea2.01d0871a.3a0d52.000d.GAE@google.com
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/serial/spcp8x5.c |   13 -------------
 1 file changed, 13 deletions(-)

--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -249,18 +249,6 @@ static void spcp8x5_set_work_mode(struct
 		dev_err(&port->dev, "failed to set work mode: %d\n", ret);
 }
 
-static int spcp8x5_carrier_raised(struct usb_serial_port *port)
-{
-	u8 msr;
-	int ret;
-
-	ret = spcp8x5_get_msr(port, &msr);
-	if (ret || msr & MSR_STATUS_LINE_DCD)
-		return 1;
-
-	return 0;
-}
-
 static void spcp8x5_dtr_rts(struct usb_serial_port *port, int on)
 {
 	struct spcp8x5_private *priv = usb_get_serial_port_data(port);
@@ -472,7 +460,6 @@ static struct usb_serial_driver spcp8x5_
 	.num_bulk_out		= 1,
 	.open			= spcp8x5_open,
 	.dtr_rts		= spcp8x5_dtr_rts,
-	.carrier_raised		= spcp8x5_carrier_raised,
 	.set_termios		= spcp8x5_set_termios,
 	.init_termios		= spcp8x5_init_termios,
 	.tiocmget		= spcp8x5_tiocmget,