GPIO子系统编写LED驱动

text.c

#include
#include 
#include 
#include 
#include 
#include 
int main(int argc, char const *argv[])
{
    char buf[128]={0};
    int fd=open("/dev/myleds",O_RDWR);
    if(fd<0)
    {
        printf("打开设备文件失败\n");
        exit(-1);
    }
    //在终端输入数据
    while(1)
    {
        printf("请输入：0（led1关灯）1（led1开灯）2（led2开灯）3（led2关灯）4（led3开灯）5（led3开灯）>>>");
        fgets(buf,sizeof(buf),stdin);
        buf[strlen(buf)-1]='\0';
        write(fd,buf,sizeof(buf));
    }
    close(fd);
    return 0;
}

驱动代码

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
/*    myleds{
    led1=<&gpioe 10 0>;
    led2=<&gpiof 10 0>;
    led3=<&gpioe 8 0>;
};*/
int major;
int gpiono;
int gpiono2;
int gpiono3;
char kbuf[128] = {0};
struct class *cls;
struct device *dev;
struct device_node *dnode;
 
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 *iof)
{
    int ret;
    //将进程2写到内核的数据传递给进程1
    if(size>sizeof(kbuf))
        size=sizeof(kbuf);
    ret=copy_to_user(ubuf,kbuf,size);
    if(ret)
    {
        printk("copy to user failed\n");
        return -EIO;
    }
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
ssize_t mycdev_write(struct file *file,const char *ubuf,size_t size,loff_t *off)
{
    int ret;
    if(size>sizeof(kbuf))
        size=sizeof(kbuf);
    ret=copy_from_user(kbuf,ubuf,size);
    if(ret)
    {
        printk("copy from user failed\n");
        return -EIO;
    }
    if(kbuf[0]=='1')
    {
        //开灯
        gpio_set_value(gpiono,1);
    }
    else if(kbuf[0]=='0')
    {
        //关灯
        gpio_set_value(gpiono,0);
    }
    else if(kbuf[0]=='2')
    {
        gpio_set_value(gpiono2,1);
    }
    else if(kbuf[0]=='3')
    {
        //关灯
        gpio_set_value(gpiono2,0);
    }
    else if(kbuf[0]=='4')
    {
        gpio_set_value(gpiono3,1);
    }
    else if(kbuf[0]=='5')
    {
        gpio_set_value(gpiono3,0);
    }
    return 0;
}
int mycdev_close(struct inode *inode,struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
//定义操作方法结构变量并初始化
struct file_operations fops=
{
    .open=mycdev_open,
    .read=mycdev_read,
    .write=mycdev_write,
    .release=mycdev_close,
};
//入口函数
static int __init mycdev_init(void)
{
    int ret;
    //进行字符设备驱动的注册
    major=register_chrdev(0,"myleds",&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lu
    cls=class_create(THIS_MODULE,"myleds");
    if(IS_ERR(cls))
    {
        printk("向上提交目錄失敗\n");
        return -PTR_ERR(cls);
    }
    printk("向上提交目录成功\n");
    //向上提交设备节点信息
    dev=device_create(cls,NULL,MKDEV(major,0),NULL,"myleds");
    if(IS_ERR(dev))
    {
        printk("向上提交设备节点失败\n");
        return -PTR_ERR(dev);
    }
    printk("向上提交设备节点成功\n");
    return 0;
 
    // 解析设备树节点
    dnode = of_find_node_by_name(NULL, "myleds");
    if (dnode == NULL)
    {
        printk("解析设备树节点失败\n");
        return -ENOMEM;
    }
    printk("解析设备树节点成功\n");
    // 根据设备树节点解析出gpio编号--led1
    gpiono = of_get_named_gpio(dnode, "led1", 0);
    if (gpiono < 0)
    {
        printk("gpio解析设备号失败\n");
        return -EIO;
    }
    // 申请gpio编号
    ret = gpio_request(gpiono, NULL);
    if (ret)
    {
        printk("GPIO编号申请失败\n");
        return -EIO;
    }
    printk("申请gpio编号成功%d\n", gpiono);
    gpiono2 = of_get_named_gpio(dnode, "led2", 0);
    if (gpiono2 < 0)
    {
        printk("gpio2解析设备号失败\n");
        return -EIO;
    }
    ret=gpio_request(gpiono2,NULL);
    if(ret)
    {
        printk("gpio2编号申请失败\n");
        return ret;
    }
    gpiono3 = of_get_named_gpio(dnode, "led3", 0);
    if (gpiono3 < 0)
    {
        printk("gpio3解析设备号失败\n");
        return -EIO;
    }
    ret=gpio_request(gpiono3,NULL);
    if(ret)
    {
        printk("gpio3编号申请失败\n");
        return ret;
    }
    printk("gpio3编号申请成功\n");
    // 设置管脚为输出
    gpio_direction_output(gpiono, 0);
    gpio_direction_output(gpiono2, 0);
    gpio_direction_output(gpiono3, 0);
    // 开灯
    //gpio_set_value(gpiono, 1);
    return 0;
}
static void __exit mycdev_exit(void)
{ 
    // 灭灯
    gpio_set_value(gpiono, 0);
    gpio_set_value(gpiono2, 0);
    gpio_set_value(gpiono3, 0);
    // 释放gpio编号
    gpio_free(gpiono);
    gpio_free(gpiono2);
    gpio_free(gpiono3);
    //销毁设备节点信息
    device_destroy(cls,MKDEV(major,0));
    //销毁目录空间
    class_destroy(cls);
    //字符设备驱动的注销
    unregister_chrdev(major,"myleds");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");
linux@linux:~/qudong/day2/