sysfs.h: add ATTRIBUTE_GROUPS() macro

commit f2f37f58 upstream.

To make it easier for driver subsystems to work with attribute groups,
create the ATTRIBUTE_GROUPS macro to remove some of the repetitive
typing for the most common use for attribute groups.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

include/linux/sysfs.h

@@ -80,6 +80,15 @@ struct attribute_group {
 
 #define __ATTR_NULL { .attr = { .name = NULL } }
 
+#define ATTRIBUTE_GROUPS(name)					\
+static const struct attribute_group name##_group = {		\
+	.attrs = name##_attrs,					\
+};								\
+static const struct attribute_group *name##_groups[] = {	\
+	&name##_group,						\
+	NULL,							\
+}
+
 #define attr_name(_attr) (_attr).attr.name
 
 struct file;