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linux:udev [2017/06/09 11:28] niziak |
linux:udev [2023/12/13 16:31] (current) niziak |
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| === Testing rules === | === Testing rules === | ||
| <code bash>udevadm test /sys/class/tty/ttyACM0</code> | <code bash>udevadm test /sys/class/tty/ttyACM0</code> | ||
| + | |||
| + | NOTE: This program is for debugging only, it does not run any program specified by a RUN key. It may show incorrect results, because some values may be different, or not available at a simulation run. | ||
| ==== Getting info ==== | ==== Getting info ==== | ||
| <code bash> | <code bash> | ||
| udevadm info --attribute-walk --path=/sys/class/tty/ttyACM0 | udevadm info --attribute-walk --path=/sys/class/tty/ttyACM0 | ||
| + | udevadm info --attribute-walk --name=/dev/ttyUSB0 | ||
| </code> | </code> | ||
| Line 23: | Line 26: | ||
| </file> | </file> | ||
| + | <code bash> | ||
| + | udevadm control --log-priority=debug | ||
| + | |||
| + | </code> | ||
| ==== Rules ==== | ==== Rules ==== | ||
| Line 94: | Line 101: | ||
| ''link_priority'': higher has higher priority | ''link_priority'': higher has higher priority | ||
| + | Define symlink name in device tree (add property ''symlink'') i.e: | ||
| + | <code> | ||
| + | &pwm4 { | ||
| + | pinctrl-names = "default"; | ||
| + | pinctrl-0 = <&pinctrl_pwm4>; | ||
| + | status = "okay"; | ||
| + | symlink = "buzzer"; | ||
| + | }; | ||
| + | </code> | ||
| + | |||
| + | <code> | ||
| + | ATTR{device/of_node/symlink}!="", ENV{DEVNAME}!="", SYMLINK+="%s{device/of_node/symlink}" | ||
| + | </code> | ||
| + | |||
| + | See: | ||
| + | - [[https://github.com/mvduin/py-uio/blob/master/dts/pwmss2.dtsi#L122|pwmss2.dtsi]] | ||
| + | - [[https://github.com/mvduin/py-uio/blob/master/etc/udev/rules.d/10-of-symlink.rules|10-of-symlink.rules]] | ||
| + | - [[https://github.com/mvduin/py-uio/blob/master/dts/pwmss2.dtsi|pwmss2.dtsi]] | ||
| === Triggering systemd === | === Triggering systemd === | ||
| Line 101: | Line 126: | ||
| SUBSYSTEM=="printer", TAG+="systemd", ENV{SYSTEMD_WANTS}="printer.target" | SUBSYSTEM=="printer", TAG+="systemd", ENV{SYSTEMD_WANTS}="printer.target" | ||
| </code> | </code> | ||
| + | |||
| + | More info about systemd interactions: [[https://www.freedesktop.org/software/systemd/man/latest/systemd.device.html|systemd.device — Device unit configuration]] | ||
| === Prevent ModemManager === | === Prevent ModemManager === | ||