On Sun, Dec 28, 2025 at 6:21 PM Shivendra Pratap
[off-list ref] wrote:

[snip]

+
+static int psci_reboot_mode_probe(struct faux_device *fdev)
+{
+       struct reboot_mode_driver *reboot;
+       struct device_node *psci_np;
+       struct device_node *np;
+       int ret;
+
+       psci_np = of_find_compatible_node(NULL, NULL, "arm,psci-1.0");
+       if (!psci_np)
+               return -ENODEV;
+
+       /*
+        * Find the psci:reboot-mode node.
+        * If NULL, continue to register predefined modes.
+        * np refcount to be handled by dev;
+        * psci_np refcount is decremented by of_find_node_by_name;
+        */

Can you make this comment into full sentences, I had trouble parsing
the meaning for a minute.

+       np = of_find_node_by_name(psci_np, "reboot-mode");
+       fdev->dev.of_node = np;

The logic of the device assigning its own node is a bit sketchy,
ideally this should be done before the device probes.

+
+       reboot = devm_kzalloc(&fdev->dev, sizeof(*reboot), GFP_KERNEL);
+       if (!reboot)
+               return -ENOMEM;
+
+       psci_reboot_mode_set_predefined_modes(reboot);
+       reboot->write = psci_reboot_mode_write;
+       reboot->dev = &fdev->dev;
+
+       ret = devm_reboot_mode_register(&fdev->dev, reboot);
+       if (ret) {
+               dev_err(&fdev->dev, "devm_reboot_mode_register failed %d\n", ret);
+               return ret;

Use dev_err_probe().

+       }
+
+       return 0;
+}
+
+static struct faux_device_ops psci_reboot_mode_ops = {
+       .probe = psci_reboot_mode_probe,
+};
+
+static int __init psci_reboot_mode_init(void)
+{
+       struct faux_device *fdev;
+
+       fdev = faux_device_create("psci-reboot-mode", NULL, &psci_reboot_mode_ops);
+       if (!fdev)
+               return -ENODEV;

This will always create this device for everyone who includes this
module. Move the of_find_compatible_node(NULL, NULL, "arm,psci-1.0")
call from probe() here instead and don't create the device if it
fails.

Bart

+
+       return 0;
+}
+device_initcall(psci_reboot_mode_init);

--
2.34.1