驱动学习5： zynq实现点亮led

最新推荐文章于 2024-11-28 10:00:00 发布

转载最新推荐文章于 2024-11-28 10:00:00 发布 · 544 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/shuqingstudy/p/9175189.html

本文介绍了一个AXI GPIO设备驱动的实现过程，包括内核模块的初始化、设备注册、文件操作函数的实现等内容，并提供了一段完整的驱动代码及应用层示例。该驱动实现了LED灯的开关控制功能。

驱动代码：

#include <linux/module.h>  
#include <linux/kernel.h>  
#include <linux/fs.h>  
#include <asm/irq.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/device.h>            //包含了device、class 等结构的定义
#include <asm/io.h>               //包含了ioremap、iowrite等内核访问IO内存等函数
#include <linux/uaccess.h>        //包含了copy_to_user、copy_from_user等
   
#define DEVICE_NAME          "axiled"
#define CLASS_NAME           "zynqebb" 

/* XGPIO Physical address */
#define XGPIO_PHY_ADDR 0x41200000      //This Address is based SDK 
/* Register Offset Definitions */
#define XGPIO_DATA_OFFSET   (0x0)    /* Data register  */
#define XGPIO_TRI_OFFSET    (0x4)    /* I/O direction register  */

volatile unsigned long *Gpio_DIR = NULL;
volatile unsigned long *Gpio_DATA = NULL;
  

MODULE_AUTHOR("Xilinx ");  
MODULE_DESCRIPTION("AXI GPIO moudle dirver");  
MODULE_VERSION("v1.0");  
MODULE_LICENSE("GPL");  
  
static int axi_gpio_driver_major;  
static struct class* axi_gpio_driver_class = NULL;  
static struct device* axi_gpio_driver_device = NULL;  
  
unsigned long axi_gpio_virt_addr = 0;        //AXI_GPIO moulde's  visual address  
  
static ssize_t axi_gpio_write(struct file * file, const char * buf, size_t count,loff_t *off)
{
    //printk("axi_gpio_write\n");
    int  val;
    copy_from_user(&val,buf,count);
    printk("before Gpio_DATA:%lx,%lx.\n",Gpio_DATA,ioread32(Gpio_DATA));
    
    if(val == 1)
    {
        //点灯
        //*Gpio_DATA = (unsigned long )0x00000005;     //设置AXI GPIO的方向输出全为高  
        iowrite32(0x0000000F,Gpio_DATA); //设置AXI GPIO的方向输出全为高  
    }
    else
    { 
        //灭灯 
        iowrite32(0x00000000,Gpio_DATA); //设置AXI GPIO的方向输出全为低  
    }
    printk("after Gpio_DATA:%lx,%lx.\n",Gpio_DATA,ioread32(Gpio_DATA));
    return 0;

}

static int axi_gpio_open(struct inode *inode, struct file *filp)
{
    //printk("axi_gpio_open\n");

    //配置led管脚为输出
    printk("before Gpio_DIR:%lx,%lx.\n",Gpio_DIR,ioread32(Gpio_DIR));
    //*Gpio_DIR = (unsigned long )0x00000000;       //设置AXI GPIO的方向输出  
    iowrite32(0x00000000,Gpio_DIR);  //设置AXI GPIO的方向输出  
    
    printk("after Gpio_DIR:%lx,%lx.\n",Gpio_DIR,ioread32(Gpio_DIR));
    
    return 0;
}
  
static struct file_operations axi_gpio_fops = {  
    .owner = THIS_MODULE,  
    .write       = axi_gpio_write,
    .open        = axi_gpio_open,
};  


static int __init axi_gpio_driver_module_init(void)  
{  
    int ret;  
  
    axi_gpio_driver_major=register_chrdev(0, DEVICE_NAME, &axi_gpio_fops );//内核注册设备驱动  
    if (axi_gpio_driver_major < 0){  
        printk("failed to register device.\n");  
        return -1;  
    }  
  
    axi_gpio_driver_class = class_create(THIS_MODULE, CLASS_NAME);//创建设备类  
    if (IS_ERR(axi_gpio_driver_class)){  
        printk("failed to create zxi_gpio moudle class.\n");  
        unregister_chrdev(axi_gpio_driver_major, DEVICE_NAME);  
        return -1;  
    }  
  
  
    axi_gpio_driver_device = device_create(axi_gpio_driver_class, NULL, MKDEV(axi_gpio_driver_major, 0), NULL, DEVICE_NAME);   
    if (IS_ERR(axi_gpio_driver_device)){  
        printk("failed to create device .\n");  
        unregister_chrdev(axi_gpio_driver_major, DEVICE_NAME);  
        return -1;  
    }  
     
     
    //To get Custom IP--gpio moudle's virtual address 
#if 1    
    if(request_mem_region(XGPIO_PHY_ADDR, 0x1000,DEVICE_NAME) == NULL ){
        printk( "request_mem_region failed\n");
        return -1;
    }
#endif  
    axi_gpio_virt_addr = (unsigned long)ioremap(XGPIO_PHY_ADDR, sizeof(u32));
    //将模块的物理地址映射到虚拟地址上  
    printk( "ioremap called: phys %#08x -> virt %#08x\n",XGPIO_PHY_ADDR, axi_gpio_virt_addr );
    //指定需要操作的寄存器的地址
    Gpio_DIR =  (unsigned long *)(axi_gpio_virt_addr + XGPIO_TRI_OFFSET);
    Gpio_DATA = (unsigned long *)(axi_gpio_virt_addr + XGPIO_DATA_OFFSET);
    
    return 0;
}  
static void __exit axi_gpio_driver_module_exit(void)  
{  

    //撤销映射关系 
    iounmap((void *)axi_gpio_virt_addr); 
#if 1
    release_mem_region(XGPIO_PHY_ADDR, 0x1000);
#endif
    device_destroy(axi_gpio_driver_class, MKDEV(axi_gpio_driver_major, 0));  
    class_unregister(axi_gpio_driver_class);  
    class_destroy(axi_gpio_driver_class);  
    unregister_chrdev(axi_gpio_driver_major, DEVICE_NAME);  
    printk("axi_gpio module exit.\n");  
}  
  
module_init(axi_gpio_driver_module_init);  
module_exit(axi_gpio_driver_module_exit);

应用层代码：

#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/axiled", O_RDWR);
    if (fd < 0)
    {
        printf("can't open!\n");
    }
    if (argc != 2)
    {
        printf("Usage :\n");
        printf("%s <on|off>\n", argv[0]);
        return 0;
    }

    if (strcmp(argv[1], "on") == 0)
    {
        val  = 1;
    }
    else
    {
        val = 0;
    }
    
    write(fd, &val, 4);
    return 0;
}

插入模块：

root@plnx_arm:/mnt# insmod mytest.ko
ioremap called: phys 0x41200000 -> virt 0xf09f0000

测试设备号：

运行应用程序:

转载于:https://www.cnblogs.com/shuqingstudy/p/9175189.html