On 12/16/20 11:43 AM, Sven Schuchmann wrote: > Hello, > I have a question regarding the assignment of spi to can channels. > At this time I see sometimes this: > > [ 6.665217] mcp251xfd spi0.0 can0: MCP2518FD rev0.0 (-RX_INT ... > [ 6.675670] mcp251xfd spi1.0 can1: MCP2518FD rev0.0 (-RX_INT ... > > and sometimes this: > > [ 6.612654] mcp251xfd spi1.0 can0: MCP2518FD rev0.0 (-RX_INT ... > [ 6.623504] mcp251xfd spi0.0 can1: MCP2518FD rev0.0 (-RX_INT ... > > Probably asked a thousand times but I did not find > a solution: How can I fix the assignment from spi0.0 to can0 > and spi1.0 to can1? The classic solution would be a udev rule in e.g. /etc/udev/rules.d/70-can.rules" > SUBSYSTEM=="net", ACTION=="add", DEVPATH=="/devices/platform/soc/*/*/*/spi0.0/net/can?", NAME="mcp0" > SUBSYSTEM=="net", ACTION=="add", DEVPATH=="/devices/platform/soc/*/*/*/spi1.0/net/can?", NAME="mcp1" > SUBSYSTEM=="net", ACTION=="add", DEVPATH=="/devices/platform/soc/*/*/*/spi2.0/net/can?", NAME="mcp2" > SUBSYSTEM=="net", ACTION=="add", DEVPATH=="/devices/platform/soc/*/*/*/spi2.1/net/can?", NAME="mcp3" Figure out the exact DEVPATH with > udevadm test /sys/class/net/can0 > udevadm test /sys/class/net/can1 Note, with older versions of udev it was possible to rename interfaces within the same namespace, e.g. use "NAME=can0". I think this doesn't work with newer udevs anymore, so in this example "mcp?" is used. The above udev-only approach is from some old documentation I found, but not tested. I'm using the modern systemd approach... The modern approach is to use systemd-networkd, this requires systemd > 246, as the older versions don't have the chip select "-cs-" in the "Path". /etc/systemd/network/70-mcp251xfd0.link: > [Match] > Driver=mcp251xfd > # RPI3 RPI4 > Path=platform-3f204000.spi-cs-0 platform-fe204000.spi-cs-0 > > [Link] > Name=mcp251xfd0 Again use "udevadm test /sys/class/net/can0", but the "Path" in the .link file corresponds to ID_PATH from udevadm test. See "man systemd.link" for details. And use this file to configure the CAN interface. /etc/systemd/network/80-can.network: > [Match] > Name=mcp251x* > > [CAN] > BitRate=500K > RestartSec=1s regards, Marc -- 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 |
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