2018年10月12日 | Tiny210驱动之LED测试

first_drv.c驱动源码：

#include "linux/device.h"

#include "linux/module.h"

#include "linux/kernel.h"

#include "linux/fs.h"

#include "linux/init.h"

#include "linux/delay.h"

#include "asm/uaccess.h"

#include "asm/irq.h"

#include "asm/io.h"

static struct class *firstdrv_class;

volatile unsigned long *gpj2con = NULL;

volatile unsigned long *gpj2dat = NULL;

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

{

    // 配置GPJ2_0,GPJ2_1,GPJ2_2,GPJ2_3为输出 

    *gpj2con &= ~((0xf<<(0*4)) | (0xf<<(1*4)) | (0xf<<(2*4)) | (0xf<<(3*4)));

    *gpj2con |= ((0x1<<(0*4)) | (0x1<<(1*4)) | (0x1<<(2*4)) | (0x1<<(3*4)));

    return 0;

}

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

{

    int val;

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

    if (val == 1)

    {

        // 点灯

        *gpj2dat &= ~((1<<0) | (1<<1) | (1<<2) | (1<<3));

    }

    else

    {

        // 灭灯

        *gpj2dat |= (1<<0) | (1<<1) | (1<<2) | (1<<3);

    }

    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");

    device_create(firstdrv_class, NULL, MKDEV(major, 0), NULL, "xyz"); // /dev/xyz 

    gpj2con = (volatile unsigned long *)ioremap(0xE0200280, 16);

    gpj2dat = gpj2con + 1;

    return 0;

}

static void first_drv_exit(void)

{

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

    device_destroy(firstdrv_class, MKDEV(major, 0));

    class_destroy(firstdrv_class);

    iounmap(gpj2con);

}

module_init(first_drv_init);

module_exit(first_drv_exit);

MODULE_LICENSE("GPL");

====================================================================

firstdrvtest.c测试程序：

#include "sys/types.h"

#include "sys/stat.h"

#include "fcntl.h"

#include "stdio.h"

// 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 《on|off》\n", argv[0]); //实际为"<"

        return 0;

    }

    if (strcmp(argv[1], "on") == 0)

    {

        val  = 1;

    }

    else

    {

        val = 0;

    }

    write(fd, &val, 4);

    return 0;

}