要求:platform驱动实现
现象:
test.c应用程序
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
int main(int argc, char const *argv[])
{
int fd;
char buf[10]={0};
fd = open("/dev/myplatform",O_RDWR);
if(fd < 0)
{
printf("打开设备文件失败\n");
exit(-1);
}
while(1)
{
memset(buf,0,sizeof(buf));
read(fd,buf,sizeof(buf));
printf("buf[0]=%d\n",buf[0]);
}
close(fd);
return 0;
}
job.c驱动程序
#include <linux/init.h>
#include <linux/module.h>
#include<linux/fs.h>
#include<linux/device.h>
#include<linux/cdev.h>
#include<linux/slab.h>
#include <linux/io.h>
#include<linux/of.h>
#include<linux/gpio.h>
#include<linux/of_gpio.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/uaccess.h>
#include<linux/mod_devicetable.h>
#include<linux/platform_device.h>
struct cdev *cdev;//字符设备驱动对象空间首地址
unsigned int major=200;//主设备号
unsigned int minor=0;//次设备号的起始值
dev_t devno;//设备号变量
char kbuf[128]={0};
struct class *cls;//存放向上提交目录的返回值
struct device *dev;//存放向上提交设备节点信息结构体
struct device_node *dnode;//设备数节点信息结构体
struct gpio_desc *gpiono;//GPIO信息结构体
char number = 0;
unsigned int irqno;//获取中断号
wait_queue_head_t wq_head;//定义一个等待队列头
unsigned int condition=0;
struct resource *res;//存放设备信息的数组首地址
unsigned int irqno;//软中断号
/*myplatform{
compatible = "hqyj,myplatform";
reg=<0X12345678 0X400>;
interrupt-parent=<&gpiof>;
interrupts=<9 0>; //9表示引用中断父节点时的索引信息 0表示默认设置
led1=<&gpioe 10 0>;
};*/
int mycdev_open(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
//size参数是用户期待读到的字节长度
int ret;
//把内核的数据再拷贝给进程
if(size>sizeof(kbuf))
size=sizeof(kbuf);
kbuf[0] = number;
if(file->f_flags & O_NONBLOCK){
//非阻塞
return -EINVAL;
}else{
//阻塞
ret = wait_event_interruptible(wq_head,condition);
if(ret < 0){
printk("receive signal....\n");
return ret;
}
}
ret=copy_to_user(ubuf,kbuf,size);
if(ret)
{
printk("数据从内核向用户拷贝失败\n");
return -EIO;
}
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
condition = 0;
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
// 定义操作方法结构体变量并赋值
struct file_operations fops =
{
.read = mycdev_read,
.open = mycdev_open,
.write = mycdev_write,
.release = mycdev_close,
};
//中断处理函数
irqreturn_t myirq_handler(int irqno, void *dev_id)
{
printk("key1 interrupt\n");
number = !number;
condition = 1;
gpiod_set_value(gpiono,!gpiod_get_value(gpiono));
wake_up_interruptible(&wq_head);
return IRQ_HANDLED;
}
//probe函数,匹配设备成功执行
int pdrv_probe(struct platform_device *pdev)
{
int ret;
//初始化等待队列头
init_waitqueue_head(&wq_head);
//1.分配字符设备驱动对象空间 cdev_alloc
cdev = cdev_alloc();
if (!cdev) {
printk(KERN_ALERT "cdev_alloc failed\n");
return -ENOMEM;
}
printk("字符设备驱动对象空间申请成功\n");
//2.字符设备驱动对象部分初始化 cdev_init
cdev_init(cdev, &fops);
//3.申请设备号 register_chrdev_region/alloc_chrdev_region
if(major>0)//静态申请设备号
{
ret=register_chrdev_region(MKDEV(major,minor),1,"myplatform");
if(ret)
{
printk("静态指定设备号失败\n");
goto out2;
}
}
else//动态申请设备号
{
ret=alloc_chrdev_region(&devno,minor,1,"myplatform");
if(ret)
{
printk("动态申请设备号失败\n");
goto out2;
}
major=MAJOR(devno);//根据设备号得到主设备号
minor=MINOR(devno);//根据设备号得到次设备号
}
printk("申请设备号成功\n");
//4.注册字符设备驱动对象 cdev_add()
ret=cdev_add(cdev,MKDEV(major,minor),1);
if(ret)
{
printk("注册字符设备驱动对象失败\n");
goto out3;
}
printk("注册字符设备驱动对象成功\n");
//5.向上提交目录
cls=class_create(THIS_MODULE,"myplatform");
if(IS_ERR(cls))
{
printk("向上提交目录失败\n");
ret=-PTR_ERR(cls);
goto out4;
}
printk("向上提交目录成功\n");
//6.向上提交设备节点
dev=device_create(cls,NULL,MKDEV(major,minor),NULL,"myplatform");
if(IS_ERR(dev))
{
printk("向上提交节点信息失败\n");
ret=-PTR_ERR(dev);
goto out5;
}
printk("向上提交设备节点信息成功\n");
/*res=platform_get_resource(pdev,IORESOURCE_MEM,0);
if(res == NULL)
{
printk("获取资源失败\n");
return -ENXIO;
}
printk("获取资源信息成功%x\n",res->start);*/
irqno = platform_get_irq(pdev,0);
if(irqno < 0)
{
printk("获取中断资源失败\n");
return irqno;
}
printk("软中断号为%d\n",irqno);
//pdev->dev.of_node 设备树匹配之后会把设备树节点结构体首地址赋值给dev的of_node成员
gpiono=gpiod_get_from_of_node(pdev->dev.of_node,"led1",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono))
{
printk("解析GPIO信息失败\n");
return -PTR_ERR(gpiono);
}
//注册中断
ret=request_irq(irqno,myirq_handler,IRQF_TRIGGER_FALLING,"myplatform",NULL);
if(ret)
{
printk("注册驱动失败\n");
return ret;
}
printk("中断注册成功\n");
return 0;
out5:
//销毁上面提交的设备信息
device_destroy(cls,MKDEV(major,minor));
class_destroy(cls);
out4:
cdev_del(cdev);
out3:
unregister_chrdev_region(MKDEV(major,minor),1);
out2:
kfree(cdev);
out1:
return ret;
}
//remove 设备和驱动分离时执行
int pdrv_remove(struct platform_device *pdev)
{
//注销中断
free_irq(irqno,NULL);
//灭灯,注销gpio信息
gpiod_set_value(gpiono,0);
gpiod_put(gpiono);
//1.销毁设备信息 device_destroy
device_destroy(cls,MKDEV(major,minor));
//2.销毁目录 class_destroy
class_destroy(cls);
//3.注销对象 cdev_del()
cdev_del(cdev);
//4.释放设备号 unregister_chrdev_region()
unregister_chrdev_region(MKDEV(major,minor),1);
//5.释放对象空间 kfree()
kfree(cdev);
return 0;
}
//用于通过设备树的形式匹配设备信息
struct of_device_id oftable[]={
{.compatible="hqyj,myplatform",},
{.compatible="hqyj,myplatform1",},
{},
};
//驱动端结构体
struct platform_driver pdrv={
.probe=pdrv_probe,
.remove=pdrv_remove,
.driver={
.name="11111",
.of_match_table=oftable,
},
};
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");