Linux 亮灯驱动代码

以下是一个简单的Linux亮灯驱动代码，可用于控制板载LED灯。

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#define DEVICE_NAME "led" // 设备名
#define LED_ON 1 // LED亮
#define LED_OFF 0 // LED灭

static int major; // 主设备号
static struct class *led_class; // 设备类
static struct device *led_device; // 设备

// 硬件地址映射
static void __iomem *gpio_base = NULL;

// LED灯控制函数
static void led_control(int status)
{
    u32 val;

    val = readl(gpio_base);
    if (status == LED_ON) {
        val &= ~(1 << 1); // LED亮
    } else {
        val |= 1 << 1; // LED灭
    }
    writel(val, gpio_base); // 写入寄存器
}

// 打开设备
static int led_open(struct inode *inode, struct file *file)
{
    return 0;
}

// 关闭设备
static int led_release(struct inode *inode, struct file *file)
{
    return 0;
}

// 读取设备
static ssize_t led_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
    return 0;
}

// 写入设备
static ssize_t led_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
    char data;
    int ret;

    ret = copy_from_user(&data, buf, sizeof(data)); // 从用户空间获取数据
    if (ret) {
        printk(KERN_ALERT "copy_from_user failed!\n");
        return -EFAULT;
    }

    led_control(data); // 控制LED灯

    return sizeof(data);
}

// 设备操作函数
static struct file_operations led_fops = {
    .owner = THIS_MODULE,
    .open = led_open,
    .release = led_release,
    .read = led_read,
    .write = led_write,
};

// 模块加载函数
static int __init led_init(void)
{
    int ret;

    printk(KERN_ALERT "led driver init!\n");

    // 映射GPIO寄存器
    gpio_base = ioremap(0x11000000, 0x100);

    // 分配主设备号
    ret = alloc_chrdev_region(&major, 0, 1, DEVICE_NAME);
    if (ret < 0) {
        printk(KERN_ALERT "alloc_chrdev_region failed!\n");
        return ret;
    }

    // 创建设备类
    led_class = class_create(THIS_MODULE, DEVICE_NAME);
    if (IS_ERR(led_class)) {
        unregister_chrdev_region(major, 1);
        printk(KERN_ALERT "class_create failed!\n");
        return PTR_ERR(led_class);
    }

    // 创建设备
    led_device = device_create(led_class, NULL, MKDEV(major, 0), NULL, DEVICE_NAME);
    if (IS_ERR(led_device)) {
        class_destroy(led_class);
        unregister_chrdev_region(major, 1);
        printk(KERN_ALERT "device_create failed!\n");
        return PTR_ERR(led_device);
    }

    // 注册设备驱动
    cdev_init(&led_cdev, &led_fops);
    led_cdev.owner = THIS_MODULE;
    ret = cdev_add(&led_cdev, MKDEV(major, 0), 1);
    if (ret < 0) {
        device_destroy(led_class, MKDEV(major, 0));
        class_destroy(led_class);
        unregister_chrdev_region(major, 1);
        printk(KERN_ALERT "cdev_add failed!\n");
        return ret;
    }

    return 0;
}

// 模块卸载函数
static void __exit led_exit(void)
{
    printk(KERN_ALERT "led driver exit!\n");

    // 注销设备驱动
    cdev_del(&led_cdev);
    device_destroy(led_class, MKDEV(major, 0));
    class_destroy(led_class);
    unregister_chrdev_region(major, 1);

    // 取消硬件地址映射
    iounmap(gpio_base);
}

module_init(led_init);
module_exit(led_exit);

MODULE_LICENSE("GPL");

这段代码包括了设备的创建、驱动的注册、硬件地址的映射、LED灯的控制等功能，可以根据实际需要进行修改。