驱动开发-按键中断

编写LED灯的驱动，使用GPIO子系统，里面添加按键的中断处理

1.应用程序发送指令控制LED亮灭

2.按键1 按下，led1电位反转 按键2按下，led2电位反转 按键3 按下，led3电位反转

功能函数

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

//功能码
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)

int main(int argc, char const *argv[])
{
    char buf[128] = {0};
    int a,b;
    int fd;
    while (1)
    {
        printf("请输入要控制的灯：0(led1) 1(led2) 2(led3)\n");
        scanf("%d",&a);
        if(a == 0)
        {
            fd = open("/dev/myled0", O_RDWR);
            if (fd < 0)
            {
                printf("打开设备文件失败\n");
                exit(-1);
            }
        }

        else if(a == 1)
        {
            fd = open("/dev/myled1", O_RDWR);
            if (fd < 0)
            {
                printf("打开设备文件失败\n");
                exit(-1);
            }
        }

        else if(a == 2)
        {
            int fd = open("/dev/myled2", O_RDWR);
            if (fd < 0)
            {
                printf("打开设备文件失败\n");
                exit(-1);
            }
        }
    
        printf("请输入控制命令:0(关闭) 1(开灯)>");

        scanf("%d",&b);
        switch(b)
        {
            case 1:
                ioctl(fd,LED_ON);
                break;
            case 0:
                ioctl(fd,LED_OFF);
                break;
        }
        close(fd);
    }

    return 0;
}

驱动代码

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


//功能码
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)

unsigned int major;//定义一个变量保存主设备号

char kbuf[128]={0};
struct class *cls;
struct device*device;


struct device_node *dev_led;
struct device_node *dev;
unsigned int irqno1,irqno2,irqno3;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;


/*
    myirq{
    interrupt-parent=<&gpiof>;//引用中断父节点
    interrupts=<9 0>,<7 0>,<8 0>;//声明和中断父节点的关系 9表示索引号，0表示默认设置
};
*/

//中断处理函数
irqreturn_t myirq_handler1(int irq,void *dev)
{

    gpiod_set_value(gpiono1, !gpiod_get_value(gpiono1)); // LED1
    return IRQ_HANDLED;
}
irqreturn_t myirq_handler2(int irq,void *dev)
{

    gpiod_set_value(gpiono2, !gpiod_get_value(gpiono2)); // LED2
    return IRQ_HANDLED;
}
irqreturn_t myirq_handler3(int irq,void *dev)
{
    gpiod_set_value(gpiono3, !gpiod_get_value(gpiono3)); // LED3
    return IRQ_HANDLED;
}

//封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
    int a = inode->i_rdev;//获取当前设备文件对应的设备号
    file->private_data=(void*)MINOR(a);//将次设备号保存到当前文件的file结构中
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}

long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    unsigned int a=(unsigned int)file->private_data;
    switch(a)
    {
        case 0:
            if(cmd == LED_ON)
            gpiod_set_value(gpiono1,1);
            else
            gpiod_set_value(gpiono1,0);
            break;   
        case 1:
            if(cmd == LED_ON)
            gpiod_set_value(gpiono2,1);
            else
            gpiod_set_value(gpiono2,0);
            break; 
        case 2:
            if(cmd == LED_ON)
            gpiod_set_value(gpiono3,1);
            else
            gpiod_set_value(gpiono3,0);
            break;                          
    }
    return 0;
}

int mycdev_close(struct inode *inode, struct file *file)
{
     printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
//定义一个操作方法结构体变量并且初始化
struct file_operations fops={
    .open=mycdev_open,
    .release=mycdev_close,
    .unlocked_ioctl = mycdev_ioctl,
};

static int __init mycdev_init(void)
{
    int i;
    // 字符设备驱动注册
    major = register_chrdev(0, "mychrdev", &fops);
    if (major < 0)
    {
        printk("字符设备驱动注册失败\n");
        return major;
    }
    printk("字符设备驱动注册成功:major=%d\n", major);
    // 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");
        return -PTR_ERR(cls);
    }
    printk("向上提交目录信息成功\n");
    // 向上提交设备节点信息
    for (i = 0; i < 3; i++)
    {
        device = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
        if (IS_ERR(device))
        {
            printk("向上提交设备节点信息失败\n");
            return -PTR_ERR(device);
        }
    }
    printk("向上提交设备节点成功\n");
    

    int ret1,ret2,ret3;
    //解析按键的设备树节点
    dev = of_find_node_by_path("/myirq");
    if(dev==NULL)
    {
        printk("解析设备树节点失败\n");
        return -EFAULT;
    }
    printk("解析设备树节点成功\n");
    //根据设备树节点的路径解析设备树信息
    dev_led = of_find_node_by_path("/leds");
    if(dev_led==NULL)
    {
        printk("解析设备树信息失败\n");
        return -EFAULT;
    }
    printk("解析设备树信息成功\n");
    
    //根据设备树节点解析出软中断号
    irqno1 = irq_of_parse_and_map(dev,0);//按键1索引号为0
    irqno2 = irq_of_parse_and_map(dev,1);//按键2索引号为1
    irqno3 = irq_of_parse_and_map(dev,2);//按键3索引号为2
    if(!irqno1|!irqno1|!irqno2)
    {
        printk("解析软中断号失败\n");
        return -ENXIO;
    }
    printk("解析软中断号成功 irqno=%d %d %d\n",irqno1,irqno2,irqno3);
    //注册中断
    ret1 = request_irq(irqno1,myirq_handler1,IRQF_TRIGGER_FALLING,"key1",NULL);
    ret2 = request_irq(irqno2,myirq_handler2,IRQF_TRIGGER_FALLING,"key2",NULL);
    ret3 = request_irq(irqno3,myirq_handler3,IRQF_TRIGGER_FALLING,"key3",NULL);
    if(ret1|ret2|ret3)
    {
        printk("注册中断失败\n");
        return -EFAULT;
    }
    printk("注册中断成功\n");

    //根据解析到的设备树信息解析出led的gpio编号
    // 申请gpio_desc对象并设置输出为低电平
    gpiono1 = gpiod_get_from_of_node(dev_led, "led1-gpios", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono1))
    {
        printk("申请gpio1对象失败\n");
        return -PTR_ERR(gpiono1);
    }
    printk("申请gpio1对象成功\n");

    gpiono2 = gpiod_get_from_of_node(dev_led, "led2-gpios", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono2))
    {
        printk("申请gpio2对象失败\n");
        return -PTR_ERR(gpiono2);
    }
    printk("申请gpio2对象成功\n");

    gpiono3 = gpiod_get_from_of_node(dev_led, "led3-gpios", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono3))
    {
        printk("申请gpio对象失败\n");
        return -PTR_ERR(gpiono3);
    }
    printk("申请gpio3对象成功\n");


    return 0;
}
static void __exit mycdev_exit(void)
{

    //销毁设备节点信息
    int i;
    for(i=0;i<3;i++)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    //销毁目录信息
    class_destroy(cls);
    //注销字符设备驱动
    unregister_chrdev(major,"mychrdev");

    //注销中断
    free_irq(irqno1,NULL);
    free_irq(irqno2,NULL);
    free_irq(irqno3,NULL);

    // 灭灯
    gpiod_set_value(gpiono1, 0);
    // 释放gpio编号
    gpiod_put(gpiono1);

    gpiod_set_value(gpiono2, 0);
    gpiod_put(gpiono2);
    
    gpiod_set_value(gpiono3, 0);
    gpiod_put(gpiono3);

}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");