struct device { struct klist klist_children; struct klist_node knode_parent; /* node in sibling list */ struct klist_node knode_driver; struct klist_node knode_bus; struct device *parent;/* 设备的 "父" 设备，该设备所属的设备，通常一个父设备是某种总线或者主控制器. 如果 parent 是 NULL, 则该设备是顶层设备，较少见 */ struct kobject kobj;/*代表该设备并将其连接到结构体系中的 kobject； 注意：作为通用的规则, device->kobj->parent 应等于 device->parent->kobj*/ char bus_id[BUS_ID_SIZE];/*在总线上唯一标识该设备的字符串;例如: PCI 设备使用标准的 PCI ID 格式, 包含:域, 总线, 设备, 和功能号.*/ struct device_type *type; unsigned is_registered:1; unsigned uevent_suppress:1; struct device_attribute uevent_attr; struct device_attribute *devt_attr; struct semaphore sem; /* semaphore to synchronize calls to its driver. */ struct bus_type * bus; /*标识该设备连接在何种类型的总线上*/ struct device_driver *driver; /*管理该设备的驱动程序*/ void *driver_data; /*该设备驱动使用的私有数据成员*/ void *platform_data; /* Platform specific data, device core doesn't touch it */ struct dev_pm_info power; #ifdef CONFIG_NUMA int numa_node; /* NUMA node this device is close to */ #endif u64 *dma_mask; /* dma mask (if dma'able device) */ u64 coherent_dma_mask;/* Like dma_mask, but for alloc_coherent mappings as not all hardware supports 64 bit addresses for consistent allocations such descriptors. */ struct list_head dma_pools; /* dma pools (if dma'ble) */ struct dma_coherent_mem *dma_mem; /* internal for coherent mem override */ /* arch specific additions */ struct dev_archdata archdata; spinlock_t devres_lock; struct list_head devres_head; /* class_device migration path */ struct list_head node; struct class *class; dev_t devt; /* dev_t, creates the sysfs "dev" */ struct attribute_group **groups; /* optional groups */ void (*release)(struct device * dev);/*当这个设备的最后引用被删除时，内核调用该方法; 它从被嵌入的 kobject 的 release 方法中调用。所有注册到核心的设备结构必须有一个 release 方法, 否则内核将打印错误信息*/ }; /*在注册 struct device 前，最少要设置parent, bus_id, bus, 和 release 成员*/ | 