经历了人生美好一刻、难过的时候，会懂得，会放弃，会怀念不断积累的平淡。那些曾经拥有的都过去了，忘记了，不再在意了，而棱角渐渐光滑，激情也慢慢消失，会同意有些事需要时间慢慢积累，也相信付出不一定会有收获，而这里，却还想欺骗自己一回，想说“一分耕耘一分收获”。
用了多年时间耗尽精力一遍遍地学那些看似应该学的东西，最后却仍觉得捉襟见肘，会伤心，会回首，忍受许多无奈。学习Linux也已经一段时间了，一些琐事断断续续，酱油也打了半瓶，一些概念也模模糊糊浮上眼帘了，对设备模型也有了一些新的认识。
基本结构体有：
struct bus_type{
const char*name;/*总线名称*/
struct bus_attribute*bus_attrs; /*总线属性*/
struct device_attribute *dev_attrs;/*该总线上所有设备的默认属性*/
struct driver_attribute *drv_attrs; /*该总线上所有驱动的默认属性*/
int (*match)(struct device *dev, struct device_driver *drv);/*驱动匹配*/
int (*uevent)(struct device *dev, struct kobj_uevent_env *env); /*添加环境变量*/
int (*probe)(struct device *dev);/*驱动匹配*/
int (*remove)(struct device *dev);/*设备移除时调用*/
void (*shutdown)(struct device *dev);/*关机时调用*/
int (*suspend)(struct device *dev, pm_message_t state);/*挂起（投入休眠）时调用*/
int (*resume)(struct device *dev);/*恢复时调用*/
struct dev_pm_ops *pm;/*设备电源管理*/
struct bus_type_private *p;/*私有数据。完全由驱动核心初始化并使用*/
};
struct bus_type_private{
struct kset subsys;/*与该总线相关的子系统*/
struct kset *drivers_kset;/*总线上驱动程序的kset*/
struct kset *devices_kset;/*挂在该总线的所有设备的kset*/
struct klist klist_devices;/*挂接在该总线的设备链表*/
struct klist klist_drivers;/*与该总线相关的驱动程序链表*/
struct blocking_notifier_head bus_notifier;
unsigned int drivers_autoprobe:1;
struct bus_type *bus;
};
struct kobj_attribute{
struct attribute attr;
ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
char *buf);
ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count);
};
struct device{
struct device*parent;//父设备，会在父设备目录下生成当前设备的目录
struct device_private*p;
struct kobject kobj;
const char*init_name; /* initial name of the device */
struct device_type*type;
struct semaphoresem;/* semaphore to synchronize calls to its driver. */
struct bus_type *bus;/* type of bus device is on */
struct device_driver *driver;/* which driver has allocated this device */
void*driver_data;/* data private to the driver */
void*platform_data; /* Platform specific data, device
core doesn't touch it */
struct dev_pm_infopower;
#ifdef CONFIG_NUMA
intnuma_node;/* NUMA node this device is close to */
#endif
u64*dma_mask;/* dma mask (if dma'able device) */
u64coherent_dma_mask;/* Like dma_mask, but for
alloc_coherent mappings as
not all hardware supports
64 bit addresses for consistent
allocations such descriptors. */
struct device_dma_parameters *dma_parms;
struct list_headdma_pools;/* dma pools (if dma'ble) */
struct dma_coherent_mem *dma_mem; /* internal for coherent mem
override */
/* arch specific additions */
struct dev_archdataarchdata;
dev_tdevt;/* dev_t, creates the sysfs "dev" */
spinlock_tdevres_lock;
struct list_headdevres_head;
struct klist_nodeknode_class;
struct class*class;
struct attribute_group**groups;/* optional groups */
void(*release)(struct device *dev);
};
struct device_private{
struct klist klist_children;
struct klist_node knode_parent;
struct klist_node knode_driver;/*作为添加到驱动的设备列表的节点*/
struct klist_node knode_bus;
struct device *device;
};
struct device_driver{
const char*name;/*驱动程序的名字(在sysfs中出现)*/
struct bus_type*bus;/*驱动程序所操作的总线类型*/
struct module*owner;
const char*mod_name;/* used for built-in modules */
int (*probe) (struct device *dev);/*查询一个特定设备是否存在及驱动是否可以使用它的函数*/
int (*remove) (struct device *dev);/*将设备从系统中删除*/
void (*shutdown) (struct device *dev);/*关闭设备*/
int (*suspend) (struct device *dev, pm_message_t state);
int (*resume) (struct device *dev);
struct attribute_group **groups;
struct dev_pm_ops *pm;
struct driver_private *p;
};
struct driver_private{
struct kobject kobj;/*内嵌的kobject对象*/
struct klist klist_devices;/*当前驱动程序能操作的设备链表*/
struct klist_node knode_bus;/*作为添加到总线的驱动列表的节点*/
struct module_kobject *mkobj;
struct device_driver *driver;
};