DESK-MX8M-L/Pheripherals/CAN
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| Version | Issue Date | Notes | |
| 1.0.0 | Jan 2022 | First DESK-MX8M release | |
Contents
Peripheral CAN[edit | edit source]
Device tree configuration[edit | edit source]
Here below an example of device tree configuration that can be used modifying DAVE's kit for the ORCA SOM:
From imx8mp-mito8mplus-cb1001.dts:
&flexcan1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_flexcan1>;
status = "okay";
};
&flexcan2 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_flexcan2>;
status = "okay";
};
From imx8mp-mito8mplus.dtsi:
pinctrl_flexcan1: flexcan1grp {
fsl,pins = <
MX8MP_IOMUXC_SAI2_TXC__CAN1_RX 0x154
MX8MP_IOMUXC_SAI5_RXD1__CAN1_TX 0x154
>;
};
pinctrl_flexcan2: flexcan2grp {
fsl,pins = <
MX8MP_IOMUXC_SAI2_MCLK__CAN2_RX 0x154
MX8MP_IOMUXC_SAI2_TXD0__CAN2_TX 0x154
>;
};
Accessing the peripheral[edit | edit source]
Linux messages at boot time[edit | edit source]
... ... [ 0.857679] CAN device driver interface [ 0.862032] flexcan 308c0000.can: 308c0000.can supply xceiver not found, using dummy regulator [ 0.871290] flexcan 308d0000.can: 308d0000.can supply xceiver not found, using dummy regulator ... ... [ 1.841605] can: controller area network core (rev 20170425 abi 9) [ 1.852275] can: raw protocol (rev 20170425) [ 1.856550] can: broadcast manager protocol (rev 20170425 t) [ 1.862220] can: netlink gateway (rev 20190810) max_hops=1
Enable the interface and check status[edit | edit source]
root@desk-mx8mp:~# ip link set can0 type can bitrate 500000 triple-sampling on
root@desk-mx8mp:~# ip link set can1 type can bitrate 500000 triple-sampling on
root@desk-mx8mp:~# ifconfig can0 up
[ 94.651224] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
root@desk-mx8mp:~# ifconfig can1 up
[ 96.465845] IPv6: ADDRCONF(NETDEV_CHANGE): can1: link becomes ready
root@desk-mx8mp:~# ifconfig can0
can0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
UP RUNNING NOARP MTU:16 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:29
root@desk-mx8mp:~# ifconfig can1
can1 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
UP RUNNING NOARP MTU:16 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:30
root@desk-mx8mp:~#
Usage with can-utils[edit | edit source]
root@desk-mx8mp:~# cansend can0 5A1#11.22.33.44.55.66.77.88 interface = can0, family = 29, ty[ 151.329908] flexcan 308c0000.can can0: bus-off pe = 3, proto = 1 root@desk-mx8mp:~#
Additional information[edit | edit source]
Each CAN port appears like a networking interface in the form canX where X is the port number.
Information about programming the CAN socket interface is given in the kernel tree under Documentation/networking/can.txt
