--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /* Copyright (c) 2020 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
+ * Copyright (c) 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
  */
 
 #ifndef _CAN_BITTIMING_H

@@ -10,6 +11,70 @@
 
 #define CAN_SYNC_SEG 1
 
+/*
+ * struct can_tdc - CAN FD Transmission Delay Compensation parameters
+ *
+ * At high bit rates, the propagation delay from the TX pin to the RX
+ * pin of the transceiver causes measurement errors: the sample point
+ * on the RX pin might occur on the previous bit.
+ *
+ * To solve this issue, ISO 11898-1 introduces in section 11.3.3
+ * "Transmitter delay compensation" a SSP (Secondary Sample Point)
+ * equal to the distance, in time quanta, from the start of the bit
+ * time on the TX pin to the actual measurement on the RX pin.
+ *
+ * This structure contains the parameters to calculate that SSP.
+ *
+ * @tdcv: Transmitter Delay Compensation Value. Distance, in time
+ *	quanta, from when the bit is sent on the TX pin to when it is
+ *	received on the RX pin of the transmitter. Possible options:
+ *
+ *	  O: automatic mode. The controller dynamically measure @tdcv
+ *	  for each transmited CAN FD frame.