| Message ID | 20221026084007.1583333-2-mkl@pengutronix.de (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 85700ac19aa19c5ff7267dc406c9bccb7a60b0e3 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,01/29] can: add termination resistor documentation | expand |
Hello: This series was applied to netdev/net-next.git (master) by Marc Kleine-Budde <mkl@pengutronix.de>: On Wed, 26 Oct 2022 10:39:39 +0200 you wrote: > From: "Daniel S. Trevitz" <dan@sstrev.com> > > Add documentation for how to use and setup the switchable termination > resistor support for CAN controllers. > > Signed-off-by: Daniel Trevitz <dan@sstrev.com> > Link: https://lore.kernel.org/all/3441354.44csPzL39Z@daniel6430 > Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> > > [...] Here is the summary with links: - [net-next,01/29] can: add termination resistor documentation https://git.kernel.org/netdev/net-next/c/85700ac19aa1 - [net-next,02/29] can: j1939: j1939_session_tx_eoma(): fix debug info https://git.kernel.org/netdev/net-next/c/de1deb156970 - [net-next,03/29] can: remove obsolete PCH CAN driver https://git.kernel.org/netdev/net-next/c/1dd1b521be85 - [net-next,04/29] can: ucan: Replace zero-length array with DECLARE_FLEX_ARRAY() helper https://git.kernel.org/netdev/net-next/c/b2df8a1bc303 - [net-next,05/29] can: kvaser_usb: Remove -Warray-bounds exception https://git.kernel.org/netdev/net-next/c/26117d92d001 - [net-next,06/29] can: m_can: is_lec_err(): clean up LEC error handling https://git.kernel.org/netdev/net-next/c/6a8836e3c24a - [net-next,07/29] can: m_can: m_can_handle_bus_errors(): add support for handling DLEC error on CAN-FD frames https://git.kernel.org/netdev/net-next/c/f5071d9e729d - [net-next,08/29] can: gs_usb: mention candleLight as supported device https://git.kernel.org/netdev/net-next/c/b1419cbebf5d - [net-next,09/29] can: gs_usb: gs_make_candev(): set netdev->dev_id https://git.kernel.org/netdev/net-next/c/acff76fa45b4 - [net-next,10/29] can: gs_usb: gs_can_open(): allow loopback and listen only at the same time https://git.kernel.org/netdev/net-next/c/deb8534e8ef3 - [net-next,11/29] can: gs_usb: gs_can_open(): sort checks for ctrlmode https://git.kernel.org/netdev/net-next/c/f6adf410f70b - [net-next,12/29] can: gs_usb: gs_can_open(): merge setting of timestamp flags and init https://git.kernel.org/netdev/net-next/c/ac3f25824e4f - [net-next,13/29] can: gs_usb: document GS_CAN_FEATURE_BERR_REPORTING https://git.kernel.org/netdev/net-next/c/1f1835264d81 - [net-next,14/29] can: gs_usb: add ability to enable / disable berr reporting https://git.kernel.org/netdev/net-next/c/2f3cdad1c616 - [net-next,15/29] can: gs_usb: document GS_CAN_FEATURE_GET_STATE https://git.kernel.org/netdev/net-next/c/40e1997d4551 - [net-next,16/29] can: gs_usb: add support for reading error counters https://git.kernel.org/netdev/net-next/c/0c9f92a4b795 - [net-next,17/29] can: kvaser_usb: kvaser_usb_leaf: Get capabilities from device https://git.kernel.org/netdev/net-next/c/35364f5b41a4 - [net-next,18/29] can: kvaser_usb: kvaser_usb_leaf: Rename {leaf,usbcan}_cmd_error_event to {leaf,usbcan}_cmd_can_error_event https://git.kernel.org/netdev/net-next/c/7ea56128dbf9 - [net-next,19/29] can: kvaser_usb: kvaser_usb_leaf: Handle CMD_ERROR_EVENT https://git.kernel.org/netdev/net-next/c/b24cb2d169e0 - [net-next,20/29] can: kvaser_usb_leaf: Set Warning state even without bus errors https://git.kernel.org/netdev/net-next/c/df1b7af2761b - [net-next,21/29] can: kvaser_usb_leaf: Fix improved state not being reported https://git.kernel.org/netdev/net-next/c/8d21f5927ae6 - [net-next,22/29] can: kvaser_usb_leaf: Fix wrong CAN state after stopping https://git.kernel.org/netdev/net-next/c/a11249acf802 - [net-next,23/29] can: kvaser_usb_leaf: Ignore stale bus-off after start https://git.kernel.org/netdev/net-next/c/abb8670938b2 - [net-next,24/29] can: kvaser_usb_leaf: Fix bogus restart events https://git.kernel.org/netdev/net-next/c/90904d326269 - [net-next,25/29] can: kvaser_usb: Add struct kvaser_usb_busparams https://git.kernel.org/netdev/net-next/c/00e578617764 - [net-next,26/29] can: kvaser_usb: Compare requested bittiming parameters with actual parameters in do_set_{,data}_bittiming https://git.kernel.org/netdev/net-next/c/39d3df6b0ea8 - [net-next,27/29] can: m_can: use consistent indention https://git.kernel.org/netdev/net-next/c/4aeb91880999 - [net-next,28/29] can: ucan: ucan_disconnect(): change unregister_netdev() to unregister_candev() https://git.kernel.org/netdev/net-next/c/aa9832e45012 - [net-next,29/29] can: rcar_canfd: Use devm_reset_control_get_optional_exclusive https://git.kernel.org/netdev/net-next/c/68399ff574e4 You are awesome, thank you!
diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst index ebc822e605f5..90121deef217 100644 --- a/Documentation/networking/can.rst +++ b/Documentation/networking/can.rst @@ -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) -----------------------------