Linux Device Drivers Development

Bus attributes

These rely on the struct bus_attribute structure:

struct bus_attribute { 
   struct attribute attr; 
   ssize_t (*show)(struct bus_type *, char * buf); 
   ssize_t (*store)(struct bus_type *, const char * buf, size_t count); 
}; 

Bus attributes are declared using the BUS_ATTR macro:

BUS_ATTR(_name, _mode, _show, _store) 

Any bus attribute declared using BUS_ATTR will have the prefix bus_attr_ added to the attribute variable name:

#define BUS_ATTR(_name, _mode, _show, _store)      \ 
struct bus_attribute bus_attr_##_name = __ATTR(_name, _mode, _show, _store) 

They are created/removed using the bus_{create|remove}_file functions:

int bus_create_file(struct bus_type *, struct bus_attribute *); void bus_remove_file(struct bus_type *, struct bus_attribute ...