On Thu, Jul 22, 2021 at 11:56 AM Viresh Kumar [off-list ref] wrote:

+/* Virtio device compatibles and IDs */
+static const struct of_device_id of_virtio_devices[] = {
+       { .compatible = "virtio,22", .data = (void *)VIRTIO_ID_I2C_ADAPTER },
+       { .compatible = "virtio,29", .data = (void *)VIRTIO_ID_GPIO },
+       { }
+};
+
+static int virtio_device_of_init(struct virtio_device *dev)
+{
+       struct device_node *np, *pnode = dev->dev.parent->of_node;
+       const struct of_device_id *match;
+       int ret, count;
+
+       if (!pnode)
+               return 0;
+
+       count = of_get_available_child_count(pnode);
+       if (!count)
+               return 0;
+
+       /* There can be only 1 child node */
+       if (WARN_ON(count > 1))
+               return -EINVAL;
+
+       np = of_get_next_available_child(pnode, NULL);
+       if (WARN_ON(!np))
+               return -ENODEV;
+
+       match = of_match_node(of_virtio_devices, np);
+       if (!match) {
+               ret = -ENODEV;
+               goto out;
+       }

I think it would be better not to have to enumerate the of_virtio_devices[]
strings, but instead use of_device_is_compatible() to match against
"virtio,%d". Otherwise we end up modifying this function for every
virtio driver that needs a binding.

       Arnd