• 20231027 基于STM32mp157a 的内核与应用层通过子系统控制led灯，以及计时器功能

    1.基于GPIO子系统编写LED驱动，编写应用程序进行测试

    stm32mp157a-fsmp1a.dts

    内核程序：ledk.c

    1. #include <linux/init.h>
    2. #include <linux/module.h>
    3. #include <linux/of.h>
    4. #include <linux/of_gpio.h>
    5. #include <linux/delay.h>
    6. #include <linux/timer.h>
    7.  
    8. struct device_node *dnode1;
    9. struct gpio_desc *gpiono1;
    10. struct gpio_desc *gpiono2;
    11. struct gpio_desc *gpiono3;
    12. struct timer_list mytimer;
    13.  
    14. unsigned int *vir_rcc;
    15. struct class *cls;
    16. struct device *dev;
    17. int major;
    18.  
    19. char kbuf[128] = {0};
    20.  
    21. //定义操作方法
    22. int mycdev_open(struct inode *inode, struct file *file)
    23. {
    24.     printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    25.     return 0;
    26. }
    27. ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
    28. {
    29.     printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    30.     int ret1=copy_to_user(ubuf,kbuf,size);
    31.     if(ret1)
    32.     {
    33.         printk("copy_to_user filed\n");
    34.         return -EIO;
    35.     }
    36.     return 0;
    37. }
    38. ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
    39. {
    40.     printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    41.     int ret=copy_from_user(kbuf,ubuf,size);
    42.     if(ret)
    43.     {
    44.         printk("copy_from_user filed\n");
    45.         return -EIO;
    46.     }
    47.     //设定该GPIO管脚的输出值
    48.     if(!strcmp(kbuf,"off"))
    49.     {
    50.         gpiod_set_value(gpiono1,0);
    51.         gpiod_set_value(gpiono2,0);
    52.         gpiod_set_value(gpiono3,0);       
    53.     }
    54.     else if(!strcmp(kbuf,"on"))
    55.     {
    56.         gpiod_set_value(gpiono1,1);
    57.         gpiod_set_value(gpiono2,1);
    58.         gpiod_set_value(gpiono3,1); 
    59.     }
    60.     return 0;
    61. }
    62. int mycdev_close(struct inode *inode, struct file *file)
    63. {
    64.  
    65.     printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    66.     return 0;
    67. }
    68. //定义操作方法结构体变量并赋值
    69. struct file_operations fops = {
    70.     .open = mycdev_open,
    71.     .read = mycdev_read,
    72.     .write = mycdev_write,
    73.     .release = mycdev_close,
    74. };
    75.  
    76. static int __init mycdev_init(void)
    77. {
    78.     // 字符设备驱动注册
    79.     major = register_chrdev(0, "mychrdev", &fops);
    80.     if (major < 0)
    81.     {
    82.         printk("字符设备驱动注册失败\n");
    83.         return major;
    84.     }
    85.     printk("字符设备驱动注册成功:major=%d\n", major);
    86.     // 向上提交目录
    87.     cls = class_create(THIS_MODULE, "mychrdev");
    88.     if (IS_ERR(cls))
    89.     {
    90.         printk("向上提交目录失败\n");
    91.         return -PTR_ERR(cls);
    92.     }
    93.     printk("向上提交目录成功\n");
    94.     // 向上提交设备节点信息
    95.     int i; // 向上提交三次设备节点信息
    96.     for (i = 0; i < 3; i++)
    97.     {
    98.         dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
    99.         if (IS_ERR(dev))
    100.         {
    101.             printk("向上提交设备节点失败\n");
    102.             return -PTR_ERR(dev);
    103.         }
    104.     }
    105.     printk("向上提交设备节点成功\n");
    106.  
    107.  
    108.     //解析设备树节点信息
    109.     dnode1 = of_find_node_by_path("/myled");
    110.     if(dnode1 == NULL)
    111.     {
    112.         printk("path_find failed \n");
    113.         return -ENXIO;
    114.     }
    115.     //根据GPIO相关节点得到GPIO编号
    116.     gpiono1 = gpiod_get_from_of_node(dnode1,"led1-gpio",0,GPIOD_OUT_LOW,NULL);
    117.     if(IS_ERR(gpiono1))
    118.     {
    119.         printk("申请gpiono1信息失败 \n");
    120.     }
    121.     printk("申请gpiono1信息成功 \n");
    122.     gpiono2 = gpiod_get_from_of_node(dnode1,"led2-gpio",0,GPIOD_OUT_LOW,NULL);
    123.     if(IS_ERR(gpiono2))
    124.     {
    125.         printk("申请gpiono2信息失败 \n");
    126.     }
    127.     printk("申请gpiono2信息成功 \n");
    128.     gpiono3 = gpiod_get_from_of_node(dnode1,"led3-gpio",0,GPIOD_OUT_LOW,NULL);
    129.     if(IS_ERR(gpiono3))
    130.     {
    131.         printk("申请gpiono3信息失败 \n");
    132.     }
    133.     printk("申请gpiono3信息成功 \n");
    134.  
    135.  
    136.     //GPIO的状态
    137.     
    138.     return 0;
    139. }
    140. static void __exit mycdev_exit(void)
    141. {
    142.     //设定该GPIO管脚的输出值
    143.     gpiod_set_value(gpiono1,0);
    144.     gpiod_set_value(gpiono2,0);
    145.     gpiod_set_value(gpiono3,0);
    146.     //释放GPIO编号
    147.     gpiod_put(gpiono1);
    148.     gpiod_put(gpiono2);
    149.     gpiod_put(gpiono3);
    150.  
    151.     // 销毁设备节点信息
    152.     int i;
    153.     for (i = 0; i < 3; i++)
    154.     {
    155.         device_destroy(cls, MKDEV(major, i));
    156.     }
    157.     // 销毁目录
    158.     class_destroy(cls);
    159.     // 注销字符设备驱动
    160.     unregister_chrdev(major, "mychrdev");
    161.  
    162. }
    163. module_init(mycdev_init);
    164. module_exit(mycdev_exit);
    165. MODULE_LICENSE("GPL");

    应用程序：ledu.c

    1. #include <stdlib.h>
    2. #include <stdio.h>
    3. #include <sys/types.h>
    4. #include <sys/stat.h>
    5. #include <sys/ioctl.h>
    6. #include <fcntl.h>
    7. #include <unistd.h>
    8. #include <string.h>
    9.  
    10. int main(int argc,const char * argv[])
    11. {
    12.     int a=0;
    13.     char buf[128] = "";
    14.     char buf1[128] = "";
    15.     int fd1=open("/dev/myled0",O_RDWR);
    16.     int fd2=open("/dev/myled1",O_RDWR);
    17.     int fd3=open("/dev/myled2",O_RDWR);
    18.     if(fd1<0)
    19.     {
    20.         printf("打开设备文件1失败\n");
    21.         exit(-1);
    22.     }
    23.     if(fd2<0)
    24.     {
    25.         printf("打开设备文件2失败\n");
    26.         exit(-1);
    27.     }
    28.     if(fd3<0)
    29.     {
    30.         printf("打开设备文件3失败\n");
    31.         exit(-1);
    32.     }
    33.  
    34.     memset(buf,0,sizeof(buf));
    35.     while(1)
    36.     {
    37.         printf("请输入灯的控制(1开灯/0关灯) => ");
    38.         scanf("%d",&a);
    39.         
    40.         write(fd1,buf,sizeof(buf));
    41.         write(fd2,buf,sizeof(buf));
    42.         write(fd3,buf,sizeof(buf));
    43.  
    44.         if(a == 1)
    45.         {
    46.             strcpy(buf,"on");
    47.             write(fd1,buf,sizeof(buf));
    48.             write(fd2,buf,sizeof(buf));
    49.             write(fd3,buf,sizeof(buf));            
    50.         }
    51.         else if(a == 0)
    52.         {
    53.             strcpy(buf,"off");
    54.             write(fd1,buf,sizeof(buf));
    55.             write(fd2,buf,sizeof(buf));
    56.             write(fd3,buf,sizeof(buf));             
    57.         }
    58.         read(fd1,buf1,sizeof(buf));
    59.         printf("buf1:%s\n",buf1);
    60.     }
    61.     return 0;
    62. }

    2.设置定时器，5秒钟打印一次hello world

    内核程序

    1. #include <linux/init.h>
    2. #include <linux/module.h>
    3. #include <linux/of.h>
    4. #include <linux/of_gpio.h>
    5. #include <linux/delay.h>
    6. #include <linux/timer.h>
    7.  
    8. struct device_node *dnode1;
    9. struct gpio_desc *gpiono1;
    10. struct gpio_desc *gpiono2;
    11. struct gpio_desc *gpiono3;
    12. struct timer_list mytimer;
    13.  
    14. char kbuf[128] = {0};
    15.  
    16. void mytimer_funtion(struct timer_list *timer)
    17. {
    18.     
    19.     //PRINTK
    20.     printk("阿巴阿巴阿巴阿巴阿巴\n");
    21.     gpiod_set_value(gpiono1,!gpiod_get_value(gpiono1));
    22.  
    23.     //启用定时器
    24.     mod_timer(timer,jiffies + msecs_to_jiffies(5000));
    25. }
    26.  
    27.  
    28. static int __init mycdev_init(void)
    29. {
    30.     //解析设备树节点信息
    31.     dnode1 = of_find_node_by_path("/myled");
    32.     if(dnode1 == NULL)
    33.     {
    34.         printk("path_find failed \n");
    35.         return -ENXIO;
    36.     }
    37.     //根据GPIO相关节点得到GPIO编号
    38.     gpiono1 = gpiod_get_from_of_node(dnode1,"led1-gpio",0,GPIOD_OUT_LOW,NULL);
    39.     if(IS_ERR(gpiono1))
    40.     {
    41.         printk("申请gpiono1信息失败 \n");
    42.     }
    43.     gpiono2 = gpiod_get_from_of_node(dnode1,"led2-gpio",0,GPIOD_OUT_LOW,NULL);
    44.     if(IS_ERR(gpiono2))
    45.     {
    46.         printk("申请gpiono2信息失败 \n");
    47.     }
    48.     gpiono3 = gpiod_get_from_of_node(dnode1,"led3-gpio",0,GPIOD_OUT_LOW,NULL);
    49.     if(IS_ERR(gpiono3))
    50.     {
    51.         printk("申请gpiono3信息失败 \n");
    52.     }
    53.     //分配定时器对象(timer_list)
    54.     //初始化定时器(timer_setup)
    55.     timer_setup(&mytimer,mytimer_funtion,0);
    56.     mytimer.expires = jiffies+HZ;
    57.     //注册定时器并启用(add_timer)
    58.     add_timer(&mytimer);
    59.  
    60.  
    61.     //GPIO的状态
    62.     
    63.     return 0;
    64. }
    65. static void __exit mycdev_exit(void)
    66. {
    67.     //设定该GPIO管脚的输出值
    68.     gpiod_set_value(gpiono1,0);
    69.     gpiod_set_value(gpiono2,0);
    70.     gpiod_set_value(gpiono3,0);
    71.     //释放GPIO编号
    72.     gpiod_put(gpiono1);
    73.     gpiod_put(gpiono2);
    74.     gpiod_put(gpiono3);
    75.     //注销定时器(del_timer)
    76.     del_timer(&mytimer);
    77.  
    78. }
    79. module_init(mycdev_init);
    80. module_exit(mycdev_exit);
    81. MODULE_LICENSE("GPL");

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  • 原文地址：https://blog.csdn.net/ainitjq1314/article/details/134083746