Linux driver _ The simplest example __linux

1.helloworld.c

#include <linux/module.h>//information related to module
 
#include <linux/kernel.h>
#include <linux/init.h >      //init-related functions
 
static int __init hellokernel_init (void)
{
        printk (kern_info "Hello kernel!\n");
        return 0;
}
 
static void __exit hellokernel_exit (void)
{
        PRINTK (kern_info "Exit kernel!\n");
}
 
 
Module_init (hellokernel_init);
Module_exit (hellokernel_exit);
 
 
Module_license ("GPL");
Module_author ("xxxx");

2.Makefile

<pre name= "code" class= "CPP" >obj-m: = HELLOWORLD.O
 
PWD       : = $ (Shell PWD) all
 
:
        make-c/lib/ modules/$ (Shell uname-r)/build m=$ (PWD) modules clean: RM-RF *.o
        core. *~ *.cmd. *.mod.c

3. Implementation and Results

Execute Make:

After the success of the compilation will generate a corresponding KO file, that is, we want to drive the

Driver-related actions:

To view the information of the KO module modinfo insert module insmod Helloworld.ko Uninstall module Rmmod HelloWorld also has a modprobe feature that later describes viewing driver printing information: Use DMESG to view the related printing information in the driver       。 Now there are examples of the following printed content:---------------------log start----------------------------[27520.195551] Exit kernel!   [27948.531569] Hello kernel! ---------------------Log End----------------------------