linux设备驱动模型 之driver（驱动）原理与实例分析

1、 驱动描述

       驱动程序由struct device_driver 描述 :

struct device_driver {
const char *name; /*驱动程序的名字( 体现在 sysfs 中 )*/
struct bus_type *bus; /*驱动程序所在的总线*/
struct module
*owner;
const char
*mod_name;
int (*probe) (struct device *dev);
int (*remove) (struct device *dev);
void (*shutdown) (struct device *dev);
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;

}

2、 驱动注册/注册

        1）int driver_register(struct device_driver *drv)

            注册驱动

       2）void driver_unregister(struct device_driver *drv)

           注销驱动

3、 驱动属性

       驱动的属性使用struct driver_attribute 来描述:

struct driver_attribute {
struct attribute attr;
ssize_t (*show)(struct device_driver *drv,
char *buf);
ssize_t (*store)(struct device_driver *drv,
const char *buf, size_t count);

}

      1）int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)

            创建属性

      2）void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)

            删除属性

4、 实例分析

       driver.c源码

#include <linux/device.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/string.h>

MODULE_AUTHOR("haha");

MODULE_LICENSE("Dual BSD/GPL");

extern struct bus_type my_bus_type;

/*当驱动找到对应的设备时会执行该函数*/

static int my_probe(struct device *dev)

{

    printk("Driver found device which my driver can handle!\n");

    return 0;

}

static int my_remove(struct device *dev)

{

    printk("Driver found device unpluged!\n");

    return 0;

}

struct device_driver my_driver = {

        .name = "my_dev",

        .bus = &my_bus_type,

        .probe = my_probe,

        .remove = my_remove,

};

static ssize_t mydriver_show(struct device_driver *driver, char *buf)

{

        return sprintf(buf, "%s\n", "This is my driver!");

}

static DRIVER_ATTR(drv, S_IRUGO, mydriver_show, NULL);

static int __init my_driver_init(void)

{

        int ret = 0;

        /*注册驱动*/

        driver_register(&my_driver);

        /*创建属性文件*/

        driver_create_file(&my_driver, &driver_attr_drv);

        return ret;

}

static void my_driver_exit(void)

{

        driver_unregister(&my_driver);

}

module_init(my_driver_init);

module_exit(my_driver_exit);

5、 试验结果





顶
1
踩