简单的平台设备驱动

dev_led：

#include<linux/init.h>
#include<linux/module.h>
#include<linux/ioport.h>
#include<linux/platform_device.h>
#include"led.h"

/*1.构建资源*/
struct resource s5pc_led_resource[]={
[0]={
.start =S5PC100_PA_LED, //0xE03001C0
.end =S5PC100_PA_LED+SZ_8-1,
.flags =IORESOURCE_MEM,
},
};

static void led_release(struct device *dev)
{

}

/*2.构建一个平台设备结构体*/
struct platform_device s5pc_led_device ={
.name ="s5pc-led",
.id =-1,
.num_resources =ARRAY_SIZE(s5pc_led_resource),
.resource =s5pc_led_resource,
.dev ={
.release =led_release,
},
};

static int __init led_dev_init(void)
{
/*3.注册平台设备
*将平台设备注册到平台总线的设备链表里面了
*/
platform_device_register(&s5pc_led_device);
return 0;
}

static void __exit led_dev_exit(void)
{
platform_device_unregister(&s5pc_led_device);
}

module_init(led_dev_init);
module_exit(led_dev_exit);
MODULE_LICENSE("GPL");

 

led_drv：

#include<linux/init.h>
#include<linux/module.h>
#include<linux/fs.h> //file_operations
#include<linux/device.h> //device_creat class_creat
#include<linux/cdev.h> //struct cdev
#include<linux/slab.h> //kamalloc
#include<asm/io.h> //ioremap writel readl
#include<asm/uaccess.h> //copy_to_user copy_from_user
#include<linux/platform_device.h> //平台
#include "led.h"

/*构建本地结构体*/
struct led_device{
struct cdev *cdev;
void __iomem *led_base;
dev_t devno;
struct class *led_class;
};

static struct led_device *s5pc_led_dev;

static int led_open(struct inode *inode, struct file *file)
{
printk(KERN_INFO "led open!\n");

return 0;
}

static ssize_t led_write(struct file *file, const char __user *buf, size_t size, loff_t *opps)
{
int ret=0;
int val;
/*获取用户空间的数据
*如果拷贝成功,则返回0
*失败返回剩下的没有拷贝成功的字节数>0
*/
ret =copy_from_user(&val,buf,size);

if(val){
/*点灯*/
writel((readl(s5pc_led_dev->led_base+S5PC100_GPG3DAT)|(0x1<<0)),s5pc_led_dev->led_base+S5PC100_GPG3DAT);
}else{
/*灭灯*/
writel((readl(s5pc_led_dev->led_base+S5PC100_GPG3DAT)&~(0x1<<0)),s5pc_led_dev->led_base+S5PC100_GPG3DAT);
}

return ret?-EFAULT:size;
}

struct file_operations led_fops={
.owner =THIS_MODULE,
.open =led_open,
.write =led_write,
};

/*3.实现probe函数,在设备资源与设备驱动匹配成功的时候,才会调用*/
static int s5pc_led_probe(struct platform_device *pdev)
{
int ret;
struct resource *res;

s5pc_led_dev=kmalloc(sizeof(struct led_device), GFP_KERNEL);

/*3.1 获取资源*/
res=platform_get_resource(pdev,IORESOURCE_MEM,0);

/*3.2 映射*/
s5pc_led_dev->led_base=ioremap(res->start, res->end-res->start+1);

/*3.3 初始化设备,操作寄存器,将GPG3[0]设置为输出*/
writel((readl(s5pc_led_dev->led_base+S5PC100_GPG3CON)&~(0xf<<0))|(0x1<<0),s5pc_led_dev->led_base+S5PC100_GPG3CON);

/*3.4 给用户提供接口*/
s5pc_led_dev->devno =MKDEV(LED_MAJOR, 0);
ret=register_chrdev_region(s5pc_led_dev->devno,1,"leds");

s5pc_led_dev->cdev=cdev_alloc();
cdev_init(s5pc_led_dev->cdev,&led_fops);
cdev_add(s5pc_led_dev->cdev,s5pc_led_dev->devno,1);

s5pc_led_dev->led_class=class_create(THIS_MODULE, "led_class");
device_create(s5pc_led_dev->led_class,NULL,s5pc_led_dev->devno,NULL,"led");

return 0;
}

/*4.实现remove函数*/
static int s5pc_led_remove(struct platform_device *pdev)
{
unregister_chrdev_region(s5pc_led_dev->devno,1);
cdev_del(s5pc_led_dev->cdev);
iounmap(s5pc_led_dev->led_base);
device_destroy(s5pc_led_dev->led_class,s5pc_led_dev->devno);
class_destroy(s5pc_led_dev->led_class);
return 0;
}

/*1.构建平台驱动结构体*/
struct platform_driver s5pc_led_driver={
.probe =s5pc_led_probe,
.remove =s5pc_led_remove,
.driver ={
.owner =THIS_MODULE,
.name ="s5pc-led",
},
};

static int __init led_dev_init(void)
{
/*2.注册平台驱动
*将平台驱动注册到平台总线的驱动链表中
*/
platform_driver_register(&s5pc_led_driver);
return 0;
}

static void __exit led_dev_exit(void)
{
platform_driver_unregister(&s5pc_led_driver);
}

module_init(led_dev_init);
module_exit(led_dev_exit);
MODULE_LICENSE("GPL");

 test：

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>

/*./led_test on 点灯
*./led_test off 灭灯
*/
int main(int argc,char **argv)
{
int fd;
int buf=0;
/*1.打开设备/打开驱动/打开设备文件*/
fd =open("/dev/led",O_RDWR);
if(fd<0){
perror("open failed");
exit(1);
}

/*2.操作硬件*/
if(strcmp(argv[1],"on")==0){
buf =1;
}else{
buf =0;
}

if(write(fd,&buf,4)!=4){
perror("write failed");
exit(1);
}
close(fd);
return 0;
}