Linux PCI driver of_node NULL when loaded

Question

I have a problem with getting a device tree information from Linux PCI driver. The driver type is pci_driver and it tries to access device tree information. When loaded, pci_dev->dev->of_node is NULL. Where pci_dev is struct pci_dev *

In my driver I have:

static const struct of_device_id casin_of_ids[] = {
    { .compatible = "ccx,casin-mfd" },
    {}
};
MODULE_DEVICE_TABLE(of, casin_of_ids);

static struct pci_driver sample_pci_mfd_driver = {
    .driver = {
        .name = "casin",
        .of_match_table = casin_of_ids,
    },
    .name = DRIVER_NAME,
    .id_table = casin_pci_ids,
    .probe = casin_pci_probe,
    .remove = casin_pci_remove,
};

Inside probe function:

if (dev->of_node) {
      of_id = of_match_device(casin_of_ids, &pci_dev->dev);
} else {
    dev->of_node = of_find_node_by_name(NULL, "casin");
    of_id = of_match_device(casin_of_ids, &pci_dev->dev);
}

I can find the node with of_find_node_by_name(NULL, "casin") if dev->of_node was NULL and afterwards when I remove and modprobe module it has the dev->of_node assigned at probe function. Is there a way to do it without manually finding name in the device tree?

Device tree:

casin {
    compatible = "ccx,casin-mfd", "simple-mfd";
    reg = <0x01000 0x1000>;

    led {
        compatible = "ccx,casin";
        offset = <0x08>;
        mask = <0x01>;
        label = "myled";
        default-state = "on";
    };
};

I need the device tree to get info about the I2C devices accessed via PCI. I have also tried do add the node under PCI node:

    pcie@33800000 {
        compatible = "fsl,imx8mm-pcie\0snps,dw-pcie";
        reg = <0x33800000 0x400000 0x1ff00000 0x80000>;
        reg-names = "dbi\0config";
        #address-cells = <0x03>;
        #size-cells = <0x02>;
        device_type = "pci";
        bus-range = <0x00 0xff>;
        ...
        ...
        pci@1,0 {
            compatible = "ccx,casin-mfd", "simple-mfd";
            status = "okay"
        };

of_node was still NULL

Running on Linux kernel v5.15.32 on imx8mm build via Yocto Kirkstone.