Termination resistor documentation
Subsystems (4)
PATCH v3 1/1 Termination resistor documentation
Add documentation for how to use and setup the switchable termination resistor support for the can-controllers.
Signed-off-by Daniel Trevitz <[email protected]>
--- Documentation/networking/can.rst | 33 ++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)
Documentation/networking/can.rst +33 -0
@@ -1148,6 +1148,39 @@ tuning on deep embedded systems'. The author is running a MPC603e load without any problems ... +Switchable Termination Resistors +-------------------------------- + +CAN bus requires a specific impedance across the differential pair, +typically provided by two 120Ohm resistors on the farthest nodes of +the bus. Some CAN controllers support activating / deactivating a +termination resistor(s) to provide the correct impedance. + +Query the available resistances:: + + $ ip -details link show can0 + ... + termination 120 [ 0, 120 ] + +Activate the terminating resistor:: + + $ ip link set dev can0 type can termination 120 + +Deactivate the terminating resistor:: + + $ ip link set dev can0 type can termination 0 + +To enable termination resistor support to a can-controller, either +implement in the controller's struct can-priv:: + + termination_const + termination_const_cnt + do_set_termination + +or add gpio control with the device tree entries from +Documentation/devicetree/bindings/net/can/can-controller.yaml + + The Virtual CAN Driver (vcan) -----------------------------
Signature · 1 line
2.35.1
Quoted 4 lines · Daniel S. Trevitz
Add documentation for how to use and setup the switchable termination resistor support for the can-controllers.
Signed-off-by Daniel Trevitz <[email protected]>
Applied to linux-can/main
Thanks,
Marc
Signature · 4 lines
Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |