驱动程序
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/cdev.h>
#include <linux/ioctl.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
struct cdev *cdev;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
unsigned int major=500;
unsigned int minor=0;//次设备号的起始值
dev_t devno;
struct class *cls;
struct device *dev;
char kbuf[128]={0};
static int number=0;
unsigned int irqno;
struct resource *res;
struct device_node *dnodel;
//定义等待队列头
wait_queue_head_t wq_head;
unsigned int condition=0;
//中断处理函数
irqreturn_t myirq_handler(int irqno, void *dev_id)
{ number=!number;printk("key1 interrupt\n");gpiod_set_value(gpiono1,!gpiod_get_value(gpiono1)); condition=1;//表示硬件数据就绪wake_up_interruptible(&wq_head);//唤醒休眠的进程return IRQ_HANDLED;
}
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)
{int ret;if(sizeof(number)<size)size=sizeof(number);wait_event_interruptible(wq_head,condition);//将进程切换为休眠ret=copy_to_user(ubuf,&number,size);if(ret){printk("copy_to_user filed\n");return -EIO;}printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);condition=0;//表示下一次硬件数据没有准备好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 = {.open = mycdev_open,.read=mycdev_read,.release = mycdev_close,
};int pdrv_probe(struct platform_device *pdev)
{ int ret,i;/****************************************************///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_alloccdev=cdev_alloc();if(cdev==NULL){printk("申请字符设备驱动对象空间失败\n");ret=-EFAULT;goto out1;}printk("字符设备驱动对象申请成功\n");//2.字符设备驱动对象部分初始化 cdev_initcdev_init(cdev,&fops);//3.申请设备号 register_chrdev_region/alloc_chrdev_regionif(major>0)//静态申请设备号{ret=register_chrdev_region(MKDEV(major,minor),3,"myled");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,3,"myled");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),3);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,"myled");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for(i=0;i<3;i++){dev=device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);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");/********************************************************///获取gpio信息//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gpiono1=gpiod_get_from_of_node(pdev->dev.of_node,"led1",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpiono1)){printk("解析GPIO信息失败\n");return -PTR_ERR(gpiono1);} //获取软中断号 irqno=platform_get_irq(pdev,0);if(irqno<0){printk("获取中断资源失败\n");return irqno;}printk("中断类型资源为%d\n",irqno);//注册中断ret=request_irq(irqno,myirq_handler,IRQF_TRIGGER_FALLING,"key1",NULL);if(ret){printk("注册驱动失败\n");return ret;}printk("key1中断注册成功\n");printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);return 0;
out5:for(--i;i>=0;i--){//销毁上面提交的设备信息device_destroy(cls,MKDEV(major,i));}class_destroy(cls);
out4:cdev_del(cdev);
out3:unregister_chrdev_region(MKDEV(major,minor),3);
out2:kfree(cdev);
out1:return ret;}
//remove 设备和驱动分离时执行
int pdrv_remove(struct platform_device *pdev)
{ //1.销毁设备信息 device_destroyint i;for(i=0;i<3;i++){device_destroy(cls,MKDEV(major,i));}//2.销毁目录 class_destroyclass_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),3);//5.释放对象空间 kfree()kfree(cdev);//注销中断free_irq(irqno,NULL);//释放gpio编号gpiod_put(gpiono1);printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);return 0;
}
struct of_device_id oftable[]={{.compatible="hqyj,myplatform",}, {.compatible="hqyj,myplatform1",}, {},
};
struct platform_driver pdrv={.probe=pdrv_probe,.remove=pdrv_remove,.driver={.name="aaaaa", .of_match_table=oftable,//设置设备树匹配},
};
//一键注册宏
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");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>
unsigned int number;
int main(int argc, char const *argv[])
{char buf[128] = {0};int fd = open("/dev/myled0", O_RDWR);if (fd < 0){printf("打开设备文件失败\n");exit(-1);}while (1){read(fd, &number, sizeof(number));printf("number:%d\n",number);}close(fd);return 0;
}实验现象
