int (*write)(struct device* dev, void* buf, size_t offset, size_t len);
int (*read_page)(struct device* dev, void* buf, size_t offset);
int (*write_page)(struct device* dev, void* buf, size_t offset);
int (*write)(struct device* dev, void* buf, size_t offset, size_t len);
int (*read_page)(struct device* dev, void* buf, size_t offset);
int (*write_page)(struct device* dev, void* buf, size_t offset);