12. Hybrid Device Driver Model

Hybrid Device Driver Model

In a Linux system, there are a class of character devices, which have the same main device number (10), but the second device number is different, we call this device a hybrid device (Miscdevice). All promiscuous devices form a linked list, and the kernel locates the corresponding promiscuous device according to the secondary device number when accessing the device.

I. Description of equipment

A struct miscdevice is used in Linux to describe a hybrid device.

1 structMiscdevice {2  　　 intMinor/*Secondary Device number*/3  　　 Const Char*name;/*Device Name*/4  　　 Const structFile_operations *fops;/*file Operations*/5  　　 structlist_head list;6  　　 structDevice *parent;7  　　 structDevice *This_device;8};

Minor is the secondary device number, name is the device name. There is also a struct file_operations structure that we need to initialize.

Second, equipment registration

Linux uses the Misc_register function to register a hybrid device driver.

int  misc_register (struct miscdevice * misc)

So to implement a hybrid device driver. The first is to initialize our miscdevice structure, and then we use the Misc_register function to register a hybrid device.

Three, hybrid device driver summary

12. Hybrid Device Driver Model