drivers: can: s32: canxl: driver does not set Transceiver Delay Compensation Offset (TDCO)

[henrikbrixandersen]

Describe the bug
The NXP S32 CANXL driver does not calculate and set the Transceiver Delay Compensation Offset (TDCO) when CAN FD is enabled. TDCO is needed for correct sampling of own TX line at higher data phase bitrates.

To Reproduce
Steps to reproduce the behavior:

1. Inspect the driver code.
2. Notice TDCO is not set up.

Expected behavior
TDCO should be calculated using CAN_CALC_TDCO() and written to the respective register and Transceiver Delay Compensation (TDC) should be enabled when using CAN FD.

Impact
Likely issues with using higher data phase bitrates.

Additional context
Please see the following commits for inspiration on how to calculate and set TDCO:

• 633065e
• bfad7bc

[manuargue]

@Dat-NguyenDuy pls have a look at this

[congnguyenhuu]

Hello @henrikbrixandersen , I tried reproducing this issue but I'm NOT possible.
I tried a test CAN traffic with multiple CAN-FD frames between 2 instance CANXL_0 and CANXL_1 on board S32Z270.

I set CAN PE clock 160MHz and bitrate for arbitration phase 125kbit/s, for data phase 8Mbit/s

I have this test for reproducing
can_fd_traffic.zip
and the result test

Do you have any suggestion about bitrate and test steps that help me to reproduce this issue. Thank you.

[henrikbrixandersen]

Hello @henrikbrixandersen , I tried reproducing this issue but I'm NOT possible. I tried a test CAN traffic with multiple CAN-FD frames between 2 instance CANXL_0 and CANXL_1 on board S32Z270.

Reproducing this greatly depends on the actual CAN tranceiver used, but nevertheless this needs to be set up.

You need to set BTDCC[FTDCEN] to enable TDC for CAN FD, calculate the TDCO using CAN_CALC_TDCO() and write it to BTDCC[FTDCOFF]. Check the reference manual chapter on "Transceiver Delay Compensation".

[congnguyenhuu]

Hello @henrikbrixandersen , I tried reproducing this issue but I'm NOT possible. I tried a test CAN traffic with multiple CAN-FD frames between 2 instance CANXL_0 and CANXL_1 on board S32Z270.

Reproducing this greatly depends on the actual CAN tranceiver used, but nevertheless this needs to be set up.

You need to set BTDCC[FTDCEN] to enable TDC for CAN FD, calculate the TDCO using CAN_CALC_TDCO() and write it to BTDCC[FTDCOFF]. Check the reference manual chapter on "Transceiver Delay Compensation".

yes, I opened PR to fix