Platform-type device automatically creates analysis "go" of device nodes in the/dev directory

Transferred from: http://blog.csdn.net/rockrockwu/article/details/7357648

System boot process platform device, the driver registration is complete, why in the/dev directory is automatically created a good device node?

The Automatically created device node in the/dev directory can be passed class_create () and then Device_create (). But in tracking

Kernel platform registration process can be found, in fact, there is no appeal two function, then platform registration

How do I create a device file node in the/dev directory?

[CPP]View PlainCopy

2. int Device_add (struct device *dev)
4. {
6. ... ...
10. if (MAJOR (dev->devt)) {
12. Error = Device_create_file (dev, &devt_attr);
14. if (Error)
16. Goto Ueventattrerror;
20. Error = Device_create_sys_dev_entry (dev);
22. if (Error)
24. Goto Devtattrerror;
28. Devtmpfs_create_node (Dev);
30. }
34. ... ...
36. }

In the process of Device_add can find the appeal code, first determine whether the dev in the device number, and some of the file creation

Finally, the device node is created in the/dev function through the function devtmpfs_dreate_node (dev).

Platform-type device automatically creates analysis "go" of device nodes in the/dev directory