Linux内核之设备驱动模型

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学习内容:总线、设备、驱动

驱动模型：
为了方便维护设备和驱动，内核抽象出三个类：

总线 struct bus_type;
设备 struct device;
驱动 struct device_driver;

这里的总线是抽象的该念总线，逻辑层面的，只是为了管理匹配
向内核注册并和总线关联的设备和驱动的，匹配规则决定于总线。
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总线对应结构体:

struct bus_type {
const char  *name; //总线的名字，注册成功后会见于/sys/bus/
const char  *dev_name;
struct device  *dev_root;
struct bus_attribute *bus_attrs;
struct device_attribute *dev_attrs;
struct driver_attribute *drv_attrs;

int (*match)(struct device *dev, struct device_driver *drv); //匹配规则

............

struct subsys_private *p;
};

int (*match)(struct device *dev, struct device_driver *drv); //匹配规则
匹配规则由编写驱动者自己定义。但是匹配成功必须返回1，否则返回0；

总线的注册：
int bus_register(struct bus_type *bus);
void bus_unregister(struct bus_type *bus);
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设备对应结构体:
struct device {
  struct device *parent;
struct device_private *p;
   struct kobject kobj;
  const char *init_name; //设备的名字,在/sys/bus/xx/devices目录下可查看
  const struct device_type *type;
  struct mutex mutex;
  struct bus_type *bus;   //用于关联的总线
  struct device_driver *driver; //匹配成功后指向设备的驱动结构体变量。
  void *platform_data;
  struct dev_pm_info power;
  struct dev_pm_domain *pm_domain;
             ..........
  struct klist_node knode_class;
  struct class  *class;
  const struct attribute_group **groups; //必须实现，当设备从内核移除时会调用此函数
  void (*release)(struct device *dev);
};

设备的注册及移除：
int device_register(struct device *dev);
void device_unregister(struct device *dev);
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驱动对应结构体:
struct device_driver {
  const char *name; //驱动的名字
  struct bus_type *bus; //驱动需要关联的总线
  struct module *owner;
  const char *mod_name;
  bool suppress_bind_attrs;
  const struct of_device_id;

int (*probe) (struct device *dev); //匹配成功，内核自动调用probe
int (*remove) (struct device *dev); //移除驱动时会自动调用remove

  void (*shutdown) (struct device *dev);
  int (*suspend) (struct device *dev, pm_message_t state);
  int (*resume) (struct device *dev);
  const struct attribute_group **groups;
  const struct dev_pm_ops *pm;

  struct driver_private *p;//很重要
};

驱动的注册及移除：
int driver_register(struct device_driver *drv)
void driver_unregister(struct device_driver *drv)

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