驱动 11/24
要求：设备树点亮板子上的所有灯
测试代码：
#include
#include
#include
#include
#include
#include
#include
char buf[128] = "";
char ubuf[128] = {0};
int main(int argc, char const *argv[])
{int fd = -1;fd = open("/dev/myled0",O_RDWR);if(-1 == fd){perror("open is error");exit(1);}while(1){printf("请输入你想操控的位置>>0：内核板 1：拓展板\n");fgets(buf,sizeof(buf),stdin);buf[strlen(buf)-1]='\0'; //去除换行printf("请输入你想开灯还是关灯>>0：关灯 1：开灯\n");fgets(buf+1,sizeof(buf),stdin);buf[strlen(buf)-1]='\0'; //去除换行printf("请输入你想操控的灯>>1：LED1 2：LED2 3：LED3\n");fgets(buf+2,sizeof(buf),stdin);buf[strlen(buf)-1]='\0'; //去除换行printf("最后的操作码为：%s\n",buf);write(fd,buf,sizeof(buf));}close(fd);return 0;
}
驱动代码
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include#define CNAME "myled"
struct cdev *cdev;
struct class * cls;
struct device * dev;
#if 1
unsigned int major = 0;//动态申请设备号
#else
unsigned int major = 500; //静态指定设备号
#endif
int minor = 0;
const int count = 1;
char kbuf[128] = "";
//定义指针指向获取到的设备节点信息
struct device_node *nhb_node;
struct device_node *tzb_node;
//用于接收到的gpio编号
struct gpio_desc * tzb_gpiono1,* tzb_gpiono2,* tzb_gpiono3;
struct gpio_desc * nhb_gpiono1,* nhb_gpiono2,* nhb_gpiono3;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 __user *ubuf, size_t size, loff_t *loff)
{int ret;printk("read:%s:%s:%d\n",__FILE__,__func__,__LINE__);if(size > sizeof(kbuf)) size = sizeof(kbuf);ret = copy_to_user(ubuf,kbuf,size);if(ret){printk("copy to user is error\n");return -EIO;}return size;return 0;
}
ssize_t mycdev_write (struct file *file, const char __user *ubuf, size_t size, loff_t *loff)
{int ret;printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);//校验传输数据大小，如果用户空间传输数据的大小大于内核空间，需要更正传输数据大小if(size > sizeof(kbuf)) size = sizeof(kbuf);ret = copy_from_user(kbuf,ubuf,size);if(ret){printk("copy from user is error\n");return -EIO;}printk("传递过来的命令为：kbuf=%s\n",kbuf);/*kbuf[0]:控制内核板还是拓展板kbuf[1]:开灯还是关灯kbuf[2]:具体的哪一盏灯*/switch(kbuf[0]){case '0'://内核switch (kbuf[1]){case '0'://关灯switch (kbuf[2]){case '1': //led1gpiod_set_value(nhb_gpiono1,0);break;case '2': //led2gpiod_set_value(nhb_gpiono2,0);break;case '3': //led3gpiod_set_value(nhb_gpiono3,0);break;default:break;}break;case '1'://开灯switch (kbuf[2]){case '1': //led1gpiod_set_value(nhb_gpiono1,1);break;case '2': //led2gpiod_set_value(nhb_gpiono2,1);break;case '3': //led3gpiod_set_value(nhb_gpiono3,1);break;default:break;}break;default:break;}case '1'://拓展板switch (kbuf[1]){case '0'://关灯switch (kbuf[2]){case '1': //led1gpiod_set_value(tzb_gpiono1,0);break;case '2': //led2gpiod_set_value(tzb_gpiono2,0);break;case '3': //led3gpiod_set_value(tzb_gpiono3,0);break;default:break;}break;case '1'://开灯switch (kbuf[2]){case '1': //led1gpiod_set_value(tzb_gpiono1,1);break;case '2': //led2gpiod_set_value(tzb_gpiono2,1);break;case '3': //led3gpiod_set_value(tzb_gpiono3,1);break;default:break;}break;default:break;}break;}return size;
}
int mycdev_close (struct inode *inode, struct file *file)
{printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);return 0;
}
const struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,
};
//入口
static int __init mycdev_init(void)
{int ret;int i;dev_t devno;//1.分配cdev结构体cdev=cdev_alloc();if(NULL==cdev){printk("分配结构体失败\n");ret = -EIO;goto ERR1;}//2.初始化结构体cdev_init(cdev,&fops);//3.申请设备号if(major>0){//静态指定设备号ret=register_chrdev_region(MKDEV(major,minor),count,CNAME);if(ret){printk("静态指定设备号失败\n");ret= -ENOMEM;goto ERR2; }}else{//动态申请设备号ret=alloc_chrdev_region(&devno,0,count,CNAME);if(ret){printk("动态指定设备号失败\n");ret= -ENOMEM;goto ERR2; }//获取主设备号major=MAJOR(devno);//获取次设备号minor=MINOR(devno);printk("动态指定设备号成功\n");} //4.驱动的注册ret=cdev_add(cdev,MKDEV(major,minor),count);if(ret){printk("驱动注册失败\n");ret=-EIO;goto ERR3;}printk("驱动注册成功\n");//5.自动创建设备节点//1)向上层提交目录信息cls=class_create(THIS_MODULE,CNAME);if(IS_ERR(cls)){printk("向上层提交目录信息失败\n");ret=PTR_ERR(cls);goto ERR4;}//2）向上层提交设备节点信息printk("向上层提交设备节点信息成功\n");for(i=0;i;led2=<&gpioz 6 0>;led3=<&gpioz 7 0>;};tzb-leds{ led1=<&gpioe 10 0>;led2=<&gpiof 10 0>;led3=<&gpioe 8 0>;}; *///通过名字获取设备树结点信息//拓展板tzb_node=of_find_node_by_name(NULL,"tzb-leds");if(tzb_node==NULL){printk("通过名字解析设备树失败\n");return -EFAULT;}printk("通过名字解析设备树成功\n");//获取并申请gpio编号tzb_gpiono1=gpiod_get_from_of_node(tzb_node,"led1",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(tzb_gpiono1)){printk("获取并申请gpio编号失败\n");return PTR_ERR(tzb_gpiono1);}tzb_gpiono2=gpiod_get_from_of_node(tzb_node,"led2",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(tzb_gpiono2)){printk("获取并申请gpio编号失败\n");return PTR_ERR(tzb_gpiono2);}tzb_gpiono3=gpiod_get_from_of_node(tzb_node,"led3",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(tzb_gpiono3)){printk("获取并申请gpio编号失败\n");return PTR_ERR(tzb_gpiono3);}printk("获取gpio编号成功\n");/* //点亮拓展板led1gpiod_set_value(tzb_gpiono1,1);gpiod_set_value(tzb_gpiono2,1);gpiod_set_value(tzb_gpiono3,1);
*/
/*****************************************************************************///内核板nhb_node=of_find_node_by_name(NULL,"nhb-leds");if(nhb_node==NULL){printk("通过名字解析设备树失败\n");return -EFAULT;}printk("通过名字解析设备树成功\n");//获取并申请gpio编号nhb_gpiono1=gpiod_get_from_of_node(nhb_node,"led1",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(nhb_gpiono1)){printk("获取并申请gpio编号失败\n");return PTR_ERR(nhb_gpiono1);}nhb_gpiono2=gpiod_get_from_of_node(nhb_node,"led2",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(nhb_gpiono2)){printk("获取并申请gpio编号失败\n");return PTR_ERR(nhb_gpiono2);}nhb_gpiono3=gpiod_get_from_of_node(nhb_node,"led3",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(nhb_gpiono3)){printk("获取并申请gpio编号失败\n");return PTR_ERR(nhb_gpiono3);}printk("获取gpio编号成功\n");
/* //点亮内核板led1gpiod_set_value(nhb_gpiono1,1);gpiod_set_value(nhb_gpiono2,1);gpiod_set_value(nhb_gpiono3,1);
*/return 0;
ERR5:for(--i;i>0;i--){device_destroy(cls,MKDEV(major,i));}
ERR4:cdev_del(cdev);
ERR3:unregister_chrdev_region(MKDEV(major,minor),count);
ERR2:kfree(cdev);
ERR1:return -EIO;
}
//出口
static void __exit mycdev_exit(void)
{int i;//1。销毁设备节点信息for(i=0;i 设备树
现象：
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