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I currently have a device that has a known PID and VID that is unique to the device and I want to use that information to find it's dev device path, like /dev/ttyUSB0.

Is this possible? So far, I have been successful in using libudev to find the correct udev_device for the pid and vid, but unsuccessful finding the path from this.

Is there any way to get this information?

    ud = udev_new();


    struct udev_enumerate *enumerate = udev_enumerate_new(ud);

    udev_enumerate_add_match_subsystem(enumerate, "usb");
    udev_enumerate_add_match_property(enumerate, "DEVTYPE", "usb_device");
    udev_enumerate_scan_devices(enumerate);

    struct udev_list_entry *devices;
    devices = udev_enumerate_get_list_entry(enumerate);

    struct udev_list_entry *dev_list_entry;
    udev_list_entry_foreach(dev_list_entry, devices)
    {
        const char *sysfs_path = udev_list_entry_get_name(dev_list_entry);
        struct udev_device *raw_dev = udev_device_new_from_syspath(ud, sysfs_path);

        uint16_t vendor_id;
        uint16_t product_id;
        udev_get_sysattr_u16_base16(raw_dev, "idVendor", &vendor_id);
        udev_get_sysattr_u16_base16(raw_dev, "idProduct", &product_id);

        if (vendor_id == VID && product_id == PID) {
            //find the device path  
        }
        
    }
dan123123
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  • Perhaps it easier for you to just skip libudev and look at the symbolic links created in `/dev/serial/by-id`. If you do want to use libudev, look at what the `lsport` example does in libusbp: https://github.com/pololu/libusbp/blob/master/examples/lsport/lsport.cpp – David Grayson Jun 26 '22 at 19:16

1 Answers1

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Try using udev-device-get-syspath or udev_device_get_devpath to find its dev device path

const char * udev_device_get_syspath (struct udev_device *udev_device);
const char *udev_device_get_devpath(struct udev_device *udev_device);

Read libudev reference manual

user16217248
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Dmitry Groker
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