net/can/mscan: add listen only mode

This patch adds listen only mode to the mscan controller.
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Acked-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/can/mscan/mscan.c

@@ -581,7 +581,10 @@ static int mscan_open(struct net_device *dev)
 
 	priv->open_time = jiffies;
 
-	clrbits8(&regs->canctl1, MSCAN_LISTEN);
+	if (ctrlmode.flags & CAN_CTRLMODE_LISTENONLY)
+		setbits8(&regs->canctl1, MSCAN_LISTEN);
+	else
+		clrbits8(&regs->canctl1, MSCAN_LISTEN);
 
 	ret = mscan_start(dev);
 	if (ret)
@@ -690,7 +693,8 @@ struct net_device *alloc_mscandev(void)
 	priv->can.bittiming_const = &mscan_bittiming_const;
 	priv->can.do_set_bittiming = mscan_do_set_bittiming;
 	priv->can.do_set_mode = mscan_do_set_mode;
-	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
+	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
+		CAN_CTRLMODE_LISTENONLY;
 
 	for (i = 0; i < TX_QUEUE_SIZE; i++) {
 		priv->tx_queue[i].id = i;