ACPI: introduce notifier change to avoid duplicates

The battery driver already registers notification handler.
To avoid registering notification handler again,
introduce a notifier chain in global system notifier handler
and use it in dock driver.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index ccae305ee55d..0dc44945725e 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -496,6 +496,19 @@ static int acpi_bus_check_scope(struct acpi_device *device)
         return 0;
 }
 
+static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
+int register_acpi_bus_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);
+
+void unregister_acpi_bus_notifier(struct notifier_block *nb)
+{
+        blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);
+
 /**
  * acpi_bus_notify
  * ---------------
@@ -506,6 +519,8 @@ static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
         int result = 0;
         struct acpi_device *device = NULL;
 
+        blocking_notifier_call_chain(&acpi_bus_notify_list,
+                type, (void *)handle);
 
         if (acpi_bus_get_device(handle, &device))
                 return;