ACPI: Add acpi_bus_attach_private_data() to attach data to ACPI handle

There is already acpi_bus_get_private_data() to get ACPI handle data
which is associated with acpi_bus_private_data_handler(). This patch
is to add acpi_bus_attach_private_data() to make a pair and facilitate
to attach and get data to/from ACPI handle.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/bus.c

@@ -132,6 +132,21 @@ void acpi_bus_private_data_handler(acpi_handle handle,
 }
 EXPORT_SYMBOL(acpi_bus_private_data_handler);
 
+int acpi_bus_attach_private_data(acpi_handle handle, void *data)
+{
+	acpi_status status;
+
+	status = acpi_attach_data(handle,
+			acpi_bus_private_data_handler, data);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_debug(handle, "Error attaching device data\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_bus_attach_private_data);
+
 int acpi_bus_get_private_data(acpi_handle handle, void **data)
 {
 	acpi_status status;
@@ -140,15 +155,20 @@ int acpi_bus_get_private_data(acpi_handle handle, void **data)
 		return -EINVAL;
 
 	status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
-	if (ACPI_FAILURE(status) || !*data) {
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
-				handle));
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_debug(handle, "No context for object\n");
 		return -ENODEV;
 	}
 
 	return 0;
 }
-EXPORT_SYMBOL(acpi_bus_get_private_data);
+EXPORT_SYMBOL_GPL(acpi_bus_get_private_data);
+
+void acpi_bus_detach_private_data(acpi_handle handle)
+{
+	acpi_detach_data(handle, acpi_bus_private_data_handler);
+}
+EXPORT_SYMBOL_GPL(acpi_bus_detach_private_data);
 
 void acpi_bus_no_hotplug(acpi_handle handle)
 {

include/acpi/acpi_bus.h

@@ -406,6 +406,8 @@ extern struct kobject *acpi_kobj;
 extern int acpi_bus_generate_netlink_event(const char*, const char*, u8, int);
 void acpi_bus_private_data_handler(acpi_handle, void *);
 int acpi_bus_get_private_data(acpi_handle, void **);
+int acpi_bus_attach_private_data(acpi_handle, void *);
+void acpi_bus_detach_private_data(acpi_handle);
 void acpi_bus_no_hotplug(acpi_handle handle);
 extern int acpi_notifier_call_chain(struct acpi_device *, u32, u32);
 extern int register_acpi_notifier(struct notifier_block *);