Linux to write a driver module that communicates with each other and add it to the kernel

Take Mini2440 For example, its Linux kernel directory is/opt/friendlyarm/mini2440/ linux-2.6.32.2, under linux-2.6.32.2 (Linux kernel directory), under the drivers directory, the new directory is named Add_sub_kconfig.

To create a new file add_sub.c,add_sub.h,test_communication.c in the Add_sub_kconfig directory, the code is as follows: (Example from "Introduction and practice of Linux Driver Development 2nd edition")

#ifndef Add_sub_h #define Add_sub_hLong add_integer (intint  b); long sub_integer (intint  b); #endif

#include <linux/init.h>#include<linux/module.h>#include"Add_sub.h"LongAdd_integer (intAintb) {    returnA +b;}LongSub_integer (intAintb) {    returnAb;} Export_symbol (Add_integer); Export_symbol (Sub_integer); Module_license ("GPL");

#include <linux/init.h>#include<linux/module.h>#include"Add_sub.h"Static intA =1;Static intb =1;Static intAddorsub =1;Static intTest_init (void){    intresult =0; PRINTK ("Test init\n"); if(Addorsub = =1) {result=Add_integer (A, b); }    Else{result=Sub_integer (A, b); } PRINTK ("The %s result is%d\n", addorsub = =1?"ADD":"Sub", result); return 0;}Static voidTest_exit (void) {PRINTK ("Test exit\n");} Module_init (Test_init); Module_exit (test_exit); Module_param (A,int, S_irugo); Module_param (b,int, S_irugo); Module_param (Addorsub,int, S_irugo); Module_license ("GPL");

Create a new Kconfig file in the Add_sub_kconfig directory with two modules, where a menu is constructed to include them. The tristate indicates that the module can be either compiled into the kernel or as a standalone module, and the default value m represents a separate module. If you want to compile directly into the kernel, you can use a Boolean and then change the default value to Y.

" add_sub_function "     "add_sub_function" config add_sub "add_sub       Support"    default  mconfig test_communicationa     "  Add_sub TestSupport"     depends on add_sub    default  Mendmenu 

Create a new makefile file in the Add_sub_kconfig directory, write add_sub and test_communication after config in Kconfig, and write Config_add_sub and config_test_ here Communication:

obj-$ (config_add_sub) + = add_sub.oobj-$ (config_test_communication) + = TEST_COMMUNICATION.O

Add the following in the Kconfig file in the drivers directory:

SOURCE "Drivers/add_sub_kconfig/kconfig"

Add the following in the makefile file in the drivers directory:

obj-$ (config_add_sub) + = add_sub_kconfig/

obj-$ (config_test_communication) + = add_sub_kconfig/

Go back to the/opt/friendlyarm/mini2440/linux-2.6.32.2 directory and execute:

Make Menuconfig, and then confirm that the module you added is already open. (choose m to compile the KO module here)

Make modules to see the two KO files compiled in the Add_sub_kconfig directory.

Download the two KO files to Mini2440 for testing.

Linux to write a driver module that communicates with each other and add it to the kernel