platform总线驱动

实现按键中断

test.c

#include <stdio.h>
#include <sys/types.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include "myled.h"
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/select.h>
#include <sys/epoll.h>
#include <signal.h>
#include <unistd.h>

int main(int argc, char const *argv[])
{
    int fd;
    char number;
    fd=open("dev/myled1",O_RDWR);
    if(fd<0)
    {
        printf("打开platform总线失败\n");
        exit(-1);
    }
    while (1)
    {
        int ret;
        ret=read(fd,&number,sizeof(char));
        if(0 == ret)
        {
            printf("读取失败\n");
            break;
        }
        printf("number=%c\n",number);

   
    }
    
     close(fd);


    return 0;
}

pdrv.c(驱动程序)

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/of.h>


#include <linux/uaccess.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of_irq.h>
 
#include <linux/device.h>
#include "myled.h"
#include <linux/io.h>
#include <linux/ioctl.h>
#include <linux/poison.h>
#include <linux/slab.h>
#include <linux/cdev.h>


struct resource *res;
int irqno;
struct gpio_desc *desc;
struct gpio_desc *desc1;

wait_queue_head_t head;
unsigned int condition;
unsigned char number;
struct cdev *cdev;
struct class* cls;
struct device* dev;
dev_t dev1;
unsigned int major;
unsigned int minor;


ssize_t mycdev_read(struct file *file, char __user *ubuf, size_t size, loff_t *loff)
{
    int ret;
    if(file->f_flags&O_NONBLOCK)
    {
        return -EINVAL;
    }else
    {
        ret=wait_event_interruptible(head,condition);
        if(ret)
        {
            printk("接收阻塞，休眠\n");
            return ret;
        }
    }
    if(size>sizeof(char))
        size=sizeof(char);
    ret=copy_to_user(ubuf,&number,size);
    if(ret)
    {
        printk("数据从内核向用户拷贝失败\n");
        return -EIO;
    }
    condition=0;
    return size;
}



//write()
ssize_t mycdev_write(struct file *file, const char __user *ubuf, size_t size, loff_t *loff)
{
       return 0;
}


int mycdev_open(struct inode *inode, struct file *file)
{
       return 0;
}




int mycdev_close(struct inode *inode, struct file *file)
{
       return 0;
}



//操作方法结构体的初始化
struct file_operations fops=
{
    .open=mycdev_open,
    .read=mycdev_read,
    .write=mycdev_write,
    //.unlocked_ioctl=ioctl,
    .release=mycdev_close,
};

//中断
irqreturn_t irq_handler(int irq,void *dev)
{
    gpiod_set_value(desc,!gpiod_get_value(desc));
    if(number =='0')
    {
        number='1';
        condition=1;
        wake_up_interruptible(&head);

    }else
    {
        number='0';
        condition=1;
        wake_up_interruptible(&head);
    }
    return IRQ_HANDLED;
}






int pdrv_probe(struct platform_device *pdr)
{
    int ret;
    printk("%s:%d\n",__FILE__,__LINE__);
    res= platform_get_resource(pdr,IORESOURCE_MEM,0);
    if(res == NULL)
    {
        printk("获取资源失败\n");
        return -ENODATA;
    }
    irqno=platform_get_irq(pdr,0);
    if(irqno<0)
    {
        printk("获取资源失败\n");
        return irqno;
    }
    printk("%#x   %d\n",res->start,irqno);

    //获取gpio编号
    desc=gpiod_get_from_of_node(pdr->dev.of_node,"led2",0,GPIOD_OUT_HIGH,NULL);
    if(IS_ERR(desc))
    {
        printk("获取GPIO编号失败\n");
        return PTR_ERR(desc);
    }

        //注册软中断号
        ret=request_irq(irqno,irq_handler,IRQF_TRIGGER_FALLING,"key2",NULL);
        if(ret)
        {
            printk("注册中断号失败\n");
            return ret;
        }
         printk("注册中断号成功\n");
         condition = 0;
         init_waitqueue_head(&head);
         return 0;

}



int pdrv_remove(struct platform_device *pdr)
{
    free_irq(irqno,NULL);
    gpiod_set_value(desc,0);
    gpiod_put(desc);


    printk("%s:%d\n",__FILE__,__LINE__);
    return 0;
}


//定义compatible表
struct of_device_id oftable[]=
{
    {.compatible="hjd,platform"},
    {},
};





MODULE_DEVICE_TABLE(of,oftable);

struct platform_driver pdrv=
{
    .probe=pdrv_probe,
    .remove=pdrv_remove,
    .driver={
        .name="test1",
        .of_match_table=oftable,  //设备树匹配
    },
    //.id_table=idtable,

};



static int __init mycdev_init(void)
{
    int ret,i;
    //1.分配对象

    cdev=cdev_alloc();
    if(cdev==NULL)
    {
        printk("cdev alloc memoory err\n");
        ret = -ENOMEM;
        goto ERR1;
    }
    printk("对象分配成功\n");


    //2.初始化对象
    cdev_init(cdev,&fops);
    
    //3.设备号的申请
        ret =alloc_chrdev_region(&dev1,0,3,"LED");
        if(ret!=0)
        {
            printk("动态申请设备号失败\n");
            goto ERR2;
        }
        major = MAJOR(dev1);
        minor = MINOR(dev1);
        printk("动态申请设备号成功\n");
 

    //4.注册字符设备驱动
    ret = cdev_add(cdev,dev1,3);
     if(ret)
        {
            printk("字符设备驱动注册失败\n");
            goto ERR3;
        }
      
        printk("注册字符设备驱动成功\n");
    //自动创建设备节点
     //向上提交目录信息
    cls=class_create(THIS_MODULE,"LED");
    if(IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        ret= PTR_ERR(cls);
        goto ERR4;
    }
    printk("向上提交目录成功\n");
    


    for(i=0;i<3;i++)
    {
        dev=device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);
        if(IS_ERR(dev))
        {
            printk("向上提交节点失败\n");
            ret = PTR_ERR(dev);
            goto ERR5;
        }
    }
    printk("向上提交节点成功\n");

    platform_driver_register(&pdrv);
 
    return 0;
ERR5:
    for(--i;i>=0;i--)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    class_destroy(cls);
ERR4:
    cdev_del(cdev);
ERR3:
    unregister_chrdev_region(dev1,3);
ERR2:
    kfree(cdev);
ERR1:
    return ret;

}





static void __exit mycdev_exit(void)
{
    int i;
    platform_driver_unregister(&pdrv);

    for(i=0;i<3;i++)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    //销毁目录
    class_destroy(cls);

    //注销字符设备驱动
    cdev_del(cdev);


   //释放设备号
    unregister_chrdev_region(dev1,3);

    kfree(cdev);

}
module_init(mycdev_init);
module_exit(mycdev_exit);


MODULE_LICENSE("GPL");
//MODULE_AUTHOR("184924447@qq.com");