Linux Embedded Drive Learning path (21) character device driver summary and introduction of block device drivers

Character device drivers

An application is a function called open Read write in a C library. In order to operate the hardware, the driver module is introduced.

Build a simple drive that has a few steps.

1. Create File_operations

2. Request a device number

3. Registering character device drivers,

4. Drive entry

5. Drive exit

Check that the data is coming in a way:

1. Query method

2. Hibernate wake-up mode

If the device fails to wake when an exception occurs, it will always be in hibernation.

3. Poll mechanism

If not awakened, you can wake yourself up for a certain amount of time.

4. Asynchronous notification (signal)

In order to enhance generality, the input subsystem is used in several ways.

Block device drivers

Sd

Linux Embedded Drive Learning path (21) character device driver summary and introduction of block device drivers