+ ssize_t (*em_show)(struct ata_port *ap, char *buf);
+ ssize_t (*em_store)(struct ata_port *ap, const char *message,
+ size_t size);
+ ssize_t (*sw_activity_show)(struct ata_device *dev, char *buf);
+ ssize_t (*sw_activity_store)(struct ata_device *dev,
+ enum sw_activity val);