ACPI: event: Redefine acpi_notifier_call_chain()

Notice that acpi_notifier_call_chain() only uses its device argument
to retrieve the pnp.device_class and pnp.bus_id values from there, so
it can be redefined to take pointers to those two strings as parameters
istead of a struct acpi_device pointer.

That allows all of its callers to pass a string literal as its first
argument, so they won't need to initialize pnp.device_class in
struct acpi_device objects operated by them any more, and its
signature becomes more similar to acpi_bus_generate_netlink_event()
then.

Update the code as per the above.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

drivers/acpi/ac.c

···
 		acpi_bus_generate_netlink_event(adev->pnp.device_class,
 						  dev_name(&adev->dev), event,
 						  (u32) ac->state);
-		acpi_notifier_call_chain(adev, event, (u32) ac->state);
+		acpi_notifier_call_chain(ACPI_AC_CLASS, acpi_device_bid(adev),
+					 event, ac->state);
 		power_supply_changed(ac->charger);
 	}
 }

drivers/acpi/acpi_video.c

···
 		break;
 	}
 
-	if (acpi_notifier_call_chain(device, event, 0))
+	if (acpi_notifier_call_chain(ACPI_VIDEO_CLASS, acpi_device_bid(device),
+				     event, 0))
 		/* Something vetoed the keypress. */
 		keycode = 0;
 
···
 		if (video_device->backlight)
 			backlight_force_update(video_device->backlight,
 					       BACKLIGHT_UPDATE_HOTKEY);
-		acpi_notifier_call_chain(device, event, 0);
+		acpi_notifier_call_chain(ACPI_VIDEO_CLASS, acpi_device_bid(device),
+					 event, 0);
 		return;
 	}
 
···
 	if (keycode)
 		may_report_brightness_keys = true;
 
-	acpi_notifier_call_chain(device, event, 0);
+	acpi_notifier_call_chain(ACPI_VIDEO_CLASS, acpi_device_bid(device),
+				 event, 0);
 
 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
 		input_report_key(input, keycode, 1);

drivers/acpi/battery.c

···
 	acpi_bus_generate_netlink_event(device->pnp.device_class,
 					dev_name(&device->dev), event,
 					acpi_battery_present(battery));
-	acpi_notifier_call_chain(device, event, acpi_battery_present(battery));
+	acpi_notifier_call_chain(ACPI_BATTERY_CLASS, acpi_device_bid(device),
+				 event, acpi_battery_present(battery));
 	/* acpi_battery_update could remove power_supply object */
 	if (old && battery->bat)
 		power_supply_changed(battery->bat);

drivers/acpi/event.c

···
 /* ACPI notifier chain */
 static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
 
-int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
+int acpi_notifier_call_chain(const char *device_class,
+			     const char *bus_id, u32 type, u32 data)
 {
 	struct acpi_bus_event event;
 
-	strscpy(event.device_class, dev->pnp.device_class);
-	strscpy(event.bus_id, dev->pnp.bus_id);
+	strscpy(event.device_class, device_class);
+	strscpy(event.bus_id, bus_id);
 	event.type = type;
 	event.data = data;
 	return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)

include/acpi/acpi_bus.h

···
 void acpi_dev_remove_notify_handler(struct acpi_device *adev,
 				    u32 handler_type,
 				    acpi_notify_handler handler);
-extern int acpi_notifier_call_chain(struct acpi_device *, u32, u32);
+extern int acpi_notifier_call_chain(const char *device_class,
+				    const char *bus_id, u32 type, u32 data);
 extern int register_acpi_notifier(struct notifier_block *);
 extern int unregister_acpi_notifier(struct notifier_block *);