linux 字符驱动视频

sudo mknod /dev/mydevice c 240 0

sudo lsof /dev/mydevice

cat /proc/interrupts

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/gpio.h>

#define DEVICE_NAME "led_driver"
#define LED_PIN 21

static int major_number;
static struct class *led_class;
static struct device *led_device;

static int led_open(struct inode *inode, struct file *file) {
    gpio_request(LED_PIN, "led_gpio");
    gpio_direction_output(LED_PIN, 0);
    return 0;
}

static int led_close(struct inode *inode, struct file *file) {
    gpio_free(LED_PIN);
    return 0;
}

static ssize_t led_write(struct file *file, const char __user *ubuf, size_t count, loff_t *ppos) {
    int value;
    copy_from_user(&value, ubuf, count);
    gpio_set_value(LED_PIN, value);
    return count;
}

static struct file_operations fops = {
    .owner = THIS_MODULE,
    .open = led_open,
    .release = led_close,
    .write = led_write,
};

static int __init led_init(void) {
    major_number = register_chrdev(0, DEVICE_NAME, &fops);
    if (major_number < 0) {
        printk(KERN_ALERT "Registering char device failed with %d\n", major_number);
        return major_number;
    }
    led_class = class_create(THIS_MODULE, DEVICE_NAME);
    if (IS_ERR(led_class)) {
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to register device class\n");
        return PTR_ERR(led_class);
    }
    led_device = device_create(led_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
    if (IS_ERR(led_device)) {
        class_destroy(led_class);
        unregister_chr储量(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to create the device\n");
        return PTR_ERR(led_device);
    }
    gpio_request(LED_PIN, "led_gpio");
    gpio_direction_output(LED_PIN, 0);
    printk(KERN_INFO "LED driver loaded\n");
    return 0;
}

static void __exit led_exit(void) {
    device_destroy(led_class, MKDEV(major_number, 0));
    class_unregister(led_class);
    class_destroy(led_class);
    unregister_chrdev(major_number, DEVICE_NAME);
    gpio_free(LED_PIN);
    printk(KERN_INFO "LED driver unloaded\n");
}

module_init(led_init);
module_exit(led_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("A simple LED driver");
MODULE_VERSION("0.1");