05-S3C2440 learning kernel (porting) linux3.4.2 porting (4) support LED driver, button driver

1. Previous work:

(1) Re-port the 3.4.2 kernel, modify the partitions, and create the jffs2 file system

http://blog.csdn.net/fengyuwuzu0519/article/details/69802922

(2) Modify the kernel to support yffs2, create a yffs2 file system, trim the kernel, and create patches

http://blog.csdn.net/fengyuwuzu0519/article/details/70162666

(3) Transplant kernel to support DM9000C network card driver (can use mount nfs) and three-way serial port

http://blog.csdn.net/fengyuwuzu0519/article/details/72846205

So far, the kernel we have ported is basically complete and includes the network card driver, but there are still too few drivers. Now we port the previously written 2.6.22 driver to linux3.4.2 to expand the system driver.

The next job:

There are many kernel upgrades, and many header files will be deleted, or some macros will be renamed or no longer used, resulting in some header files in the driver being no longer valid and some functions being unable to be used as before. Therefore, when we modify the driver, we mainly address the function changes brought about by the kernel upgrade, because the compilation of the driver depends on the kernel.

2. Transplant linux2.26LED, button and other drivers to 3.4.2 kernel

1. Driver migration method between kernels

1. Compile

2. Solve the error

2.1 Wrong header file: remove or rename

2.2 Wrong macro: rename and use a new macro

2.3 Some functions are gone: rename and use new functions

2. Transplantation process

(1) Transplant LED driver

Update the kernel directory in the kernel, which needs to be compiled in advance

Make directly and see what errors there are

Some header files no longer exist, just remove them and see

Compile again

If there is a problem with the class_create declaration, then see how other kernel drivers use this function.

It should be the missing header file, including:

Compile again

I found that this function is black, so it should be no longer used. So search for class_create.

The function name is changed to: device_create

The export function is renamed to: device_destroy(firstdrv_class, MKDEV(major, 0));

Compile successfully and copy to the board

Loading Driver

This is the LED driver transplantation result.

(2) Transplanting the key driver

Modify the makefile and then make directly

Add the above header files

Pin declaration is gone

See which function is used, kernel search

The solution is given below

Continue compiling

After this is expanded, there is this variable, which should be due to some headers not being included.

Missing header file, see how others use this function

Continue compiling

How to use the search request_irq

The name of the macro has changed. How to use this function?

Many drivers are similar, we can modify them by comparing the software:

Continue compiling:

Uninstall error:

The function parameters have changed

Kill the application that uses it before uninstalling the driver.