Key knowledge of embedded driver

1. What is a drive ？ Drive down operation hardware , Interface up , Simply put, you used to configure hardware registers to make the hardware work normally , Then you first configure the hardware in the same way in the driver , It's just about when to put the process of configuring hardware into the framework of the driver , At the same time, provide your hardware operation interface to the outside , such as open,read,write,ioctl And so on , To put it bluntly, it is through the application layer io Operate to call the interface of the driver, and then modify the state of the hardware in the interface provided by the driver , Realize the control of hardware . Of course, some basic knowledge such as spin lock , mutex , Interrupt the bottom half and so on. You can learn by yourself .
Only take down the drive , We can open the whole closed loop from the bottom hardware to the top application, and then from the top application to the bottom driver , We will find that many things are small for us case Of course. .
2. The environment needs to be built , We need to know how to compile the kernel , How to run the kernel on the board .
3. The first drive must also light up .
4. stay linux Write a simple character device driver .
5. After learning, you will find that the driver is basically in the framework , For example, character device framework ,Platform frame ,IIC frame ,SPI frame ,INPUT Input subsystem framework ,misc,USB And so on .