2019年11月14日 | TQ2440开发板 Linux第一个驱动--点灯

我用的是TQ2440开发板,这个程序是参考韦东山的.

4盏LED灯

以下是驱动程序

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

static struct class *firstdrv_class;

static struct class_device        *firstdrv_class_dev;

volatile unsigned long *gpbcon = NULL;

volatile unsigned long *gpbdat = NULL;

static int first_drv_open(struct inode *inode, struct file *file)

{

        //printk("first_drv_openn");

        /* 配置gpb5,6,7,8为输出 */

        *gpbcon &= ~((0x3<<(5*2)) | (0x3<<(6*2)) | (0x3<<(7*2)) | (0x3<<(8*2)));

        *gpbcon |= ((0x1<<(5*2)) |(0x1<<(6*2)) | (0x1<<(7*2)) | (0x1<<(8*2)));

        return 0;

}

static ssize_t first_drv_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)

{

        int val;

        //printk("first_drv_writen");

        copy_from_user(&val, buf, count); //        copy_to_user();

        if (val == 1)

        {

                // 点灯

                *gpbdat &= ~((1<<5) | (1<<6) | (1<<7) | (1<<8));

        }

        else

        {

                // 灭灯

                *gpbdat |= (1<<5) | (1<<6) | (1<<7) | (1<<8);

        }

        return 0;

}

static struct file_operations first_drv_fops = {

    .owner  =   THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */

    .open   =   first_drv_open,     

        .write        =        first_drv_write,           

};

int major;

static int first_drv_init(void)

{

        major = register_chrdev(0, "first_drv", &first_drv_fops); // 注册, 告诉内核

        firstdrv_class = class_create(THIS_MODULE, "firstdrv");

        firstdrv_class_dev = class_device_create(firstdrv_class, NULL, MKDEV(major, 0), NULL, "xyz"); /* /dev/xyz */

        gpbcon = (volatile unsigned long *)ioremap(0x56000010, 16); //0x56000010是的GPIOB的

        gpbdat = gpbcon + 1;

        printk("first_drv_init...n");

        return 0;

}

static void first_drv_exit(void)

{

        unregister_chrdev(major, "first_drv"); // 卸载

        class_device_unregister(firstdrv_class_dev);

        class_destroy(firstdrv_class);

        iounmap(gpbcon);

        printk("first_drv_exit...n");

}

module_init(first_drv_init);

module_exit(first_drv_exit);

MODULE_LICENSE("GPL");

以下是测试程序

#include

#include

#include

#include

/* firstdrvtest on

  * firstdrvtest off

  */

int main(int argc, char **argv)

{

        int fd;

        int val = 1;

        fd = open("/dev/xyz", O_RDWR);

        if (fd < 0)

        {

                printf("can't open!n");

        }

        if (argc != 2)

        {

                printf("Usage :n");

                printf("%s n", argv[0]);

                return 0;

        }

        if (strcmp(argv[1], "on") == 0)

        {

                val  = 1;

        }

        else

        {

                val = 0;

        }

        write(fd, &val, 4);

        return 0;

}