驱动开发 day9

text.c

#include 

int main(int argc, const char* argv[])
{
    int fd;
    int status;

    if ((fd = open("/dev/platform_irq_led", O_RDWR)) == -1) {
        perror("open error");
        exit(EXIT_FAILURE);
    }

    while (1) {
        read(fd, &status, sizeof(status));
        printf("status = %d\n", status);
    }
    close(fd);
    return 0;
}

demo.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define CNAME "platform_irq_led"
int major;
struct class *cls;
struct device *dev;
wait_queue_head_t wq;
unsigned int condition=0;
unsigned int status=0;
struct gpio_desc *desc;
unsigned int irqno;

irqreturn_t irq_led_handle(int irq, void *dev)
{
    status = gpiod_get_value(desc);
    status = !status;
    gpiod_set_value(desc,status);

    condition=1;
    wake_up_interruptible(&wq);

    return IRQ_HANDLED;
}
int irq_led_open(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t irq_led_read(struct file *file, 
    char __user *ubuf, size_t size, loff_t *offs)
{
    int ret;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    if(file->f_flags & O_NONBLOCK){
        //非阻塞
        return -EINVAL;
    }else{
        //阻塞
        ret = wait_event_interruptible(wq,condition);
        if(ret < 0){
            printk("receive signal....\n");
            return ret;
        }
    }
    //将数据拷贝到用户空间
    if(size > sizeof(status)) size = sizeof(status);
    ret = copy_to_user(ubuf,(void *)&status,size);
    if(ret){
        printk("copy data to user error\n");
        return -EIO;
    }

    //4.将条件清零
    condition = 0;

    return size;
}
int irq_led_close(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
struct file_operations fops = {
    .open = irq_led_open,
    .read = irq_led_read,
    .release = irq_led_close,
};
int pdrv_probe(struct platform_device* pdev) //在进入probe函数的时候节点已经被放在pdev->dev.of_node中了
{
   int ret;
    //1.注册字符设备驱动
    major = register_chrdev(0,CNAME,&fops);
    if(major < 0){
        printk("register char device driver error\n");
        ret = major;
        goto ERR1;
    }
    //2.创建设备节点
    cls = class_create(THIS_MODULE,CNAME);
    if(IS_ERR(cls)){
        printk("class create error\n");
        ret = PTR_ERR(cls);
        goto ERR2;
    }
    dev = device_create(cls,NULL,MKDEV(major,0),NULL,CNAME);
    if(IS_ERR(dev)){
        printk("device create error\n");
        ret = PTR_ERR(dev);
        goto ERR3;
    }
    //3.初始化等待队列头
    init_waitqueue_head(&wq);
   
    desc = gpiod_get_from_of_node(pdev->dev.of_node,"led1",0,GPIOD_OUT_LOW,NULL);
    if(IS_ERR(desc)){
        printk("get gpiod error\n");
        ret = PTR_ERR(desc);
        goto ERR4;
    }

    irqno = platform_get_irq(pdev,0);  //获取中断的信息
    if(irqno < 0){
        printk("get irq resource error\n");
        ret = irqno;
        goto ERR5;
    }
    
    ret = request_irq(irqno,irq_led_handle,IRQF_TRIGGER_FALLING,CNAME,NULL);
    if(ret){
        printk("request irq error\n");
        goto ERR5;
    }

    return 0;
ERR5:
    gpiod_put(desc);
ERR4:
    device_destroy(cls,MKDEV(major,0));
ERR3:
    class_destroy(cls);
ERR2:
    unregister_chrdev(major,CNAME);
ERR1:
    return ret;
}
int pdrv_remove(struct platform_device* pdev)
{
    printk("%s:%d\n", __func__, __LINE__);
    free_irq(irqno,NULL);
    gpiod_put(desc);
    device_destroy(cls,MKDEV(major,0));
    class_destroy(cls);
    unregister_chrdev(major,CNAME);
    return 0;
}
struct of_device_id oftable[] = {
    {.compatible = "hqyj,platform",},
    {/*end*/},
};


struct platform_driver pdrv = {
    .probe = pdrv_probe,
    .remove = pdrv_remove,
    .driver = {
        .name = "hahaha",
        .of_match_table = oftable,
    },
    
};
//这个宏能够实现入口，出口，注册，注销的过程
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");