#define IF_COMM_CLR_NEWDAT     IF_COMM_TXRQST
 #define IF_COMM_DATAA          BIT(1)
 #define IF_COMM_DATAB          BIT(0)
-#define IF_COMM_ALL            (IF_COMM_MASK | IF_COMM_ARB | \
-                               IF_COMM_CONTROL | IF_COMM_TXRQST | \
-                               IF_COMM_DATAA | IF_COMM_DATAB)
+
+/* TX buffer setup */
+#define IF_COMM_TX             (IF_COMM_ARB | IF_COMM_CONTROL | \
+                                IF_COMM_TXRQST |                \
+                                IF_COMM_DATAA | IF_COMM_DATAB)
 
 /* For the low buffers we clear the interrupt bit, but keep newdat */
 #define IF_COMM_RCV_LOW                (IF_COMM_MASK | IF_COMM_ARB | \
 #define IF_MCONT_RCV           (IF_MCONT_RXIE | IF_MCONT_UMASK)
 #define IF_MCONT_RCV_EOB       (IF_MCONT_RCV | IF_MCONT_EOB)
 
+#define IF_MCONT_TX            (IF_MCONT_TXIE | IF_MCONT_EOB)
+
 /*
  * Use IF1 for RX and IF2 for TX
  */
        c_can_obj_update(dev, iface, cmd | IF_COMM_WR, obj);
 }
 
-static void c_can_write_msg_object(struct net_device *dev,
-                       int iface, struct can_frame *frame, int objno)
+static void c_can_write_msg_object(struct net_device *dev, int iface,
+                                  struct can_frame *frame, int obj)
 {
-       int i;
-       u16 flags = 0;
-       unsigned int id;
        struct c_can_priv *priv = netdev_priv(dev);
-
-       if (!(frame->can_id & CAN_RTR_FLAG))
-               flags |= IF_ARB_TRANSMIT;
+       u16 ctrl = IF_MCONT_TX | frame->can_dlc;
+       u32 arb = IF_ARB_MSGVAL << 16;
+       int i;
 
        if (frame->can_id & CAN_EFF_FLAG) {
-               id = frame->can_id & CAN_EFF_MASK;
-               flags |= IF_ARB_MSGXTD;
-       } else
-               id = ((frame->can_id & CAN_SFF_MASK) << 18);
+               arb |= frame->can_id & CAN_EFF_MASK;
+               arb |= IF_ARB_MSGXTD << 16;
+       } else {
+               arb |= (frame->can_id & CAN_SFF_MASK) << 18;
+       }
 
-       flags |= IF_ARB_MSGVAL;
+       if (!(frame->can_id & CAN_RTR_FLAG))
+               arb |= IF_ARB_TRANSMIT << 16;
+
+       priv->write_reg(priv, C_CAN_IFACE(ARB1_REG, iface), arb);
+       priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface), arb >> 16);
 
-       priv->write_reg(priv, C_CAN_IFACE(ARB1_REG, iface),
-                               IFX_WRITE_LOW_16BIT(id));
-       priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface), flags |
-                               IFX_WRITE_HIGH_16BIT(id));
+       priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), ctrl);
 
        for (i = 0; i < frame->can_dlc; i += 2) {
                priv->write_reg(priv, C_CAN_IFACE(DATA1_REG, iface) + i / 2,
                                frame->data[i] | (frame->data[i + 1] << 8));
        }
 
-       /* enable interrupt for this message object */
-       priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface),
-                       IF_MCONT_TXIE | IF_MCONT_TXRQST | IF_MCONT_EOB |
-                       frame->can_dlc);
-       c_can_object_put(dev, iface, objno, IF_COMM_ALL);
+       c_can_object_put(dev, iface, obj, IF_COMM_TX);
 }
 
 static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev,