can: move sanity check for bitrate and tq into can_get_bittiming

This patch moves a sanity check in order to have a second user for CAN FD.
Also simplify the return value generation in can_get_bittiming() as only
correct return values of can_[calc|fixup]_bittiming() lead to a return value of
zero.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index de04eac7c5f3867d7b87981e0ca4f9753a64407f..e5f1faf36d8ffe56bd283a4c951cc2f5ff94a32b 100644 (file)
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -260,20 +260,23 @@ static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
        int err;
 
        /* Check if the CAN device has bit-timing parameters */
-       if (priv->bittiming_const) {
+       if (!priv->bittiming_const)
+               return 0;
 
-               /* Non-expert mode? Check if the bitrate has been pre-defined */
-               if (!bt->tq)
-                       /* Determine bit-timing parameters */
-                       err = can_calc_bittiming(dev, bt);
-               else
-                       /* Check bit-timing params and calculate proper brp */
-                       err = can_fixup_bittiming(dev, bt);
-               if (err)
-                       return err;
-       }
+       /*
+        * Depending on the given can_bittiming parameter structure the CAN
+        * timing parameters are calculated based on the provided bitrate OR
+        * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
+        * provided directly which are then checked and fixed up.
+        */
+       if (!bt->tq && bt->bitrate)
+               err = can_calc_bittiming(dev, bt);
+       else if (bt->tq && !bt->bitrate)
+               err = can_fixup_bittiming(dev, bt);
+       else
+               err = -EINVAL;
 
-       return 0;
+       return err;
 }
 
 /*
@@ -667,8 +670,6 @@ static int can_changelink(struct net_device *dev,
                if (dev->flags & IFF_UP)
                        return -EBUSY;
                memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
-               if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
-                       return -EINVAL;
                err = can_get_bittiming(dev, &bt);
                if (err)
                        return err;