+ /*
+ * Dell Airplane Mode Switch driver (dell-rbtn) supports ACPI devices
+ * which can receive events from HW slider switch.
+ *
+ * Dell SMBIOS on whitelisted models supports controlling radio devices
+ * but does not support receiving HW button switch events. We can use
+ * i8042 filter hook function to receive keyboard data and handle
+ * keycode for HW button.
+ *
+ * So if it is possible we will use Dell Airplane Mode Switch ACPI
+ * driver for receiving HW events and Dell SMBIOS for setting rfkill
+ * states. If ACPI driver or device is not available we will fallback to
+ * i8042 filter hook function.
+ *
+ * To prevent duplicate rfkill devices which control and do same thing,
+ * dell-rbtn driver will automatically remove its own rfkill devices
+ * once function dell_rbtn_notifier_register() is called.
+ */
+
+ dell_rbtn_notifier_register_func =
+ symbol_request(dell_rbtn_notifier_register);
+ if (dell_rbtn_notifier_register_func) {
+ dell_rbtn_notifier_unregister_func =
+ symbol_request(dell_rbtn_notifier_unregister);
+ if (!dell_rbtn_notifier_unregister_func) {
+ symbol_put(dell_rbtn_notifier_register);
+ dell_rbtn_notifier_register_func = NULL;
+ }
+ }
+
+ if (dell_rbtn_notifier_register_func) {
+ ret = dell_rbtn_notifier_register_func(
+ &dell_laptop_rbtn_notifier);
+ symbol_put(dell_rbtn_notifier_register);
+ dell_rbtn_notifier_register_func = NULL;
+ if (ret != 0) {
+ symbol_put(dell_rbtn_notifier_unregister);
+ dell_rbtn_notifier_unregister_func = NULL;
+ }
+ } else {
+ pr_info("Symbols from dell-rbtn acpi driver are not available\n");
+ ret = -ENODEV;
+ }
+
+ if (ret == 0) {
+ pr_info("Using dell-rbtn acpi driver for receiving events\n");
+ } else if (ret != -ENODEV) {
+ pr_warn("Unable to register dell rbtn notifier\n");