Implementing a character driver

• Four major steps

• Implement operations corresponding to the system calls an application can apply to a file: file operations
• Define a file_operations structure associating function pointers to their implementation in your driver
• Reserve a set of major and minors for your driver
• Tell the kernel to associate the reserved major and minor to your file operations

• This is a very common design scheme in the Linux kernel

• A common kernel infrastructure defines a set of operations to be implemented by a driver and functions to register your driver
• Your driver only needs to implement this set of well-defined operations