河间网站制作,百度站长平台网站收录,百度系app有哪些,营销策划方案步骤首先#xff0c;如果对platform设备和驱动的注册机制不熟悉的话#xff0c;可以先看一下大神的博客 http://blog.csdn.net/zqixiao_09/article/details/50888795
一、下面逐一分析一下每一个函数的功能 1、platform_device_register //把设备注册到platform bus上
1)plat…首先如果对platform设备和驱动的注册机制不熟悉的话可以先看一下大神的博客 http://blog.csdn.net/zqixiao_09/article/details/50888795
一、下面逐一分析一下每一个函数的功能 1、platform_device_register //把设备注册到platform bus上
1)platform_device_add
2)pdev-dev.bus platform_bus_type; //指明设备要挂载总线类型
3)device_add
4)bus_add_device //把设备放到相应的总线上面
5)bus_probe_device
6)device_attach //尝试绑定相应的驱动
7)bus_for_each_drv
8)__device_attach
9)driver_match_device //调用platform_match匹配相应的驱动,先匹配id table再返回比较驱动的名字
//1、注册设备前驱动已经注册那么则会继续执行相应设备的probe函数
//2、如果注册设备前驱动没有被注册那么就仅把设备注册到总线上
10)driver_probe_device(drv, dev)
11)really_probe(dev, drv)
12)dev-bus-probe(dev)/drv-probe(dev) //执行驱动的probe对设备进行初始化
13)put_device //把设备放进内核
2、platform_driver_register //把驱动注册到platform bus上
1)drv-driver.bus platform_bus_type;//指明驱动要挂载总线类型
2)driver_register
3)bus_add_driver //把driver添加到bus上面
4)driver_attach
5)bus_for_each_dev //查找相应的设备是否已经在总线上注册
6)__driver_attach(struct device * dev, void * data)
7)driver_match_device(drv, dev) //与上面platform_match的一样
//1、注册驱动前设备已经注册那么则会继续执行相应设备的probe函数
//2、如果注册驱动前设备没有被注册那么就仅把驱动注册到总线上
8)driver_probe_device(drv, dev)
9)really_probe(dev, drv)
10)dev-bus-probe(dev)/drv-probe(dev) //执行驱动的probe对设备进行初始化
11)klist_add_tail(priv-knode_bus, bus-p-klist_drivers); //把driver放在bus
下面分析一下关键函数int bus_add_driver(struct device_driver *drv){......if (drv-bus-p-drivers_autoprobe) {error driver_attach(drv); //驱动开始匹配设备if (error)goto out_unregister;}......}int driver_attach(struct device_driver *drv){return bus_for_each_dev(drv-bus, NULL, drv, __driver_attach); //在bus上面轮询匹配设备}//遍历bus的函数int bus_for_each_dev(struct bus_type *bus, struct device *start,void *data, int (*fn)(struct device *, void *)){struct klist_iter i;struct device *dev;int error 0;if (!bus)return -EINVAL;klist_iter_init_node(bus-p-klist_devices, i,(start ? start-p-knode_bus : NULL));while ((dev next_device(i)) !error)error fn(dev, data); klist_iter_exit(i);return error;}//实际的匹配函数static int __driver_attach(struct device *dev, void *data){struct device_driver *drv data;/** Lock device and try to bind to it. We drop the error* here and always return 0, because we need to keep trying* to bind to devices and some drivers will return an error* simply if it didnt support the device.** driver_probe_device() will spit a warning if there* is an error.*///如果没有找到相应的设备 则退出if (!driver_match_device(drv, dev)) return 0;//如果找到相应的设备 则执行driver的probe对设备进行初始化工作if (dev-parent) /* Needed for USB */device_lock(dev-parent);device_lock(dev);if (!dev-driver)driver_probe_device(drv, dev);device_unlock(dev);if (dev-parent)device_unlock(dev-parent);return 0;}
3、device_register 其实device_register就是platform_device_register的父本platform_device_register在device_register的基础上添加了platform_device一些个性的内容如果没有把设备注册成platform device的情况一般都会使用device_register来注册设备如misc_register注册设备时。
4、driver_register driver_register也一样就是platform_driver_register的父本。
二、下面结合实例说明一下
#include linux/init.h
#include linux/module.h
#include linux/device.h
#include linux/platform_device.h
#include linux/miscdevice.h
#include linux/fs.h#define DRIVER_NAME hello_driver//用于在总线上适配的驱动名字
#define DEVICE_NAME hello_device//生成的设备节点名字static int hello_release(struct inode *inode, struct file *file){printk(hello release\n);return 0;
}static int hello_open(struct inode *inode, struct file *file){printk(hello open\n);return 0;
}static struct file_operations hello_ops {.owner THIS_MODULE,.open hello_open,.release hello_release,
};static struct miscdevice hello_dev {.minor MISC_DYNAMIC_MINOR,.name DEVICE_NAME,//设备节点名.fops hello_ops,
};//如果总线匹配成功 就会执行probe函数
static int hello_probe(struct platform_device *pdv){printk(hello_probe\n);misc_register(hello_dev);return 0;
}static int hello_remove(struct platform_device *pdv){printk(hello_remove\n);misc_deregister(hello_dev);return 0;
}static void hello_shutdown(struct platform_device *pdv){;
}static int hello_suspend(struct platform_device *pdv,pm_message_t pmt){return 0;
}static int hello_resume(struct platform_device *pdv){return 0;
}//创建设备
static struct platform_device hello_device
{ .name DRIVER_NAME, //用于总线匹配.id -1,
}; //创建驱动
struct platform_driver hello_driver {.probe hello_probe,.remove hello_remove,.shutdown hello_shutdown,.suspend hello_suspend,.resume hello_resume,.driver {.name DRIVER_NAME, //用于总线匹配.owner THIS_MODULE,}
};static int hello_init(void)
{int DriverState;platform_device_register(hello_device);printk(KERN_EMERG hello_init!\n);//打印信息使用dmesg查看//执行platform_driver_register后 适配完 就会执行//hello_probe即先打印hello_probe信息才会打印//tDriverState信息DriverState platform_driver_register(hello_driver);printk(KERN_EMERG \tDriverState is %d\n,DriverState);return 0;
}static void hello_exit(void)
{printk(KERN_EMERG hello_exit!\n);platform_driver_unregister(hello_driver); platform_device_unregister(hello_device);
}module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE(GPL);
