dock: add 'type' sysfs file

add a sysfs file to present dock type. Suggested by Holger.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/acpi/dock.c

@@ -911,6 +911,26 @@ static ssize_t show_dock_uid(struct device *dev,
 }
 static DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);
 
+static ssize_t show_dock_type(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct dock_station *dock_station = *((struct dock_station **)
+		dev->platform_data);
+	char *type;
+
+	if (dock_station->flags & DOCK_IS_DOCK)
+		type = "dock_station";
+	else if (dock_station->flags & DOCK_IS_ATA)
+		type = "ata_bay";
+	else if (dock_station->flags & DOCK_IS_BAT)
+		type = "battery_bay";
+	else
+		type = "unknown";
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", type);
+}
+static DEVICE_ATTR(type, S_IRUGO, show_dock_type, NULL);
+
 /**
  * dock_add - add a new dock station
  * @handle: the dock station handle
@@ -999,6 +1019,9 @@ static int dock_add(acpi_handle handle)
 		dock_station = NULL;
 		return ret;
 	}
+	ret = device_create_file(&dock_device->dev, &dev_attr_type);
+	if (ret)
+		printk(KERN_ERR"Error %d adding sysfs file\n", ret);
 
 	/* Find dependent devices */
 	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
@@ -1020,6 +1043,7 @@ static int dock_add(acpi_handle handle)
 	return 0;
 
 dock_add_err_unregister:
+	device_remove_file(&dock_device->dev, &dev_attr_type);
 	device_remove_file(&dock_device->dev, &dev_attr_docked);
 	device_remove_file(&dock_device->dev, &dev_attr_undock);
 	device_remove_file(&dock_device->dev, &dev_attr_uid);
@@ -1047,6 +1071,7 @@ static int dock_remove(struct dock_station *dock_station)
 	    kfree(dd);
 
 	/* cleanup sysfs */
+	device_remove_file(&dock_device->dev, &dev_attr_type);
 	device_remove_file(&dock_device->dev, &dev_attr_docked);
 	device_remove_file(&dock_device->dev, &dev_attr_undock);
 	device_remove_file(&dock_device->dev, &dev_attr_uid);