net: can: ifi: Configure transmitter delay

Configure the transmitter delay register at +0x1c to correctly handle
the CAN FD bitrate switch (BRS). This moves the SSP (secondary sample
point) to a proper offset, so that the TDC mechanism works and won't
generate error frames on the CAN link.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/net/can/ifi_canfd/ifi_canfd.c b/drivers/net/can/ifi_canfd/ifi_canfd.c
index 2d1d22eec750..368bb0710d8f 100644
--- a/drivers/net/can/ifi_canfd/ifi_canfd.c
+++ b/drivers/net/can/ifi_canfd/ifi_canfd.c
@@ -81,6 +81,10 @@
 #define IFI_CANFD_TIME_SET_TIMEA_4_12_6_6       BIT(15)
 
 #define IFI_CANFD_TDELAY                        0x1c
+#define IFI_CANFD_TDELAY_DEFAULT                0xb
+#define IFI_CANFD_TDELAY_MASK                   0x3fff
+#define IFI_CANFD_TDELAY_ABS                    BIT(14)
+#define IFI_CANFD_TDELAY_EN                     BIT(15)
 
 #define IFI_CANFD_ERROR                         0x20
 #define IFI_CANFD_ERROR_TX_OFFSET               0
@@ -641,7 +645,7 @@ static void ifi_canfd_set_bittiming(struct net_device *ndev)
         struct ifi_canfd_priv *priv = netdev_priv(ndev);
         const struct can_bittiming *bt = &priv->can.bittiming;
         const struct can_bittiming *dbt = &priv->can.data_bittiming;
-        u16 brp, sjw, tseg1, tseg2;
+        u16 brp, sjw, tseg1, tseg2, tdc;
 
         /* Configure bit timing */
         brp = bt->brp - 2;
@@ -664,6 +668,11 @@ static void ifi_canfd_set_bittiming(struct net_device *ndev)
                (brp << IFI_CANFD_TIME_PRESCALE_OFF) |
                (sjw << IFI_CANFD_TIME_SJW_OFF_7_9_8_8),
                priv->base + IFI_CANFD_FTIME);
+
+        /* Configure transmitter delay */
+        tdc = (dbt->brp * (dbt->phase_seg1 + 1)) & IFI_CANFD_TDELAY_MASK;
+        writel(IFI_CANFD_TDELAY_EN | IFI_CANFD_TDELAY_ABS | tdc,
+               priv->base + IFI_CANFD_TDELAY);
 }
 
 static void ifi_canfd_set_filter(struct net_device *ndev, const u32 id,