driver/3-new-led/new_char.c

/*
 * @Author: error: error: git config user.name & please set dead value or install git && error: git config user.email & please set dead value or install git & please set dead value or install git
 * @Date: 2023-08-19 09:31:52
 * @LastEditors: error: error: git config user.name & please set dead value or install git && error: git config user.email & please set dead value or install git & please set dead value or install git
 * @LastEditTime: 2023-08-19 10:42:49
 * @FilePath: /3-new-led/led.c
 * @Description: 这是默认设置,请设置`customMade`, 打开koroFileHeader查看配置 进行设置: https://github.com/OBKoro1/koro1FileHeader/wiki/%E9%85%8D%E7%BD%AE
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
/***
 * configuration
 */
// DEV_NAME
#define dev_name "newchr"
// DEV_ID配置
#define DEV_ID_STATIC 1
#if DEV_ID_STATIC
#define DEV_ID_MAJOR 80
#define DEV_ID_MINOR 0
#endif
struct _dev_info
{
    dev_t dev_id;
    struct cdev cdev;
    struct class *class;
    struct device *device;
} dev_info = {0};

/***
 * code
 */
static ssize_t tis_module_read(struct file *file, char __user *out, size_t size, loff_t *offt)
{
    printk("%s: module read\n", dev_name);
    return 0;
}
static ssize_t tis_module_write(struct file *file, const char __user *in, size_t size, loff_t *offt)
{
    printk("%s: module write\n", dev_name);
    return 0;
}
static int tis_module_open(struct inode *inode, struct file *file)
{
    printk("%s: module open\n", dev_name);
    return 0;
}

static int tis_module_release(struct inode *inode, struct file *file)
{
    printk("%s: module release\n", dev_name);
    return 0;
}
static struct file_operations tis_module_f = {
    .owner = THIS_MODULE,
    .write = tis_module_write,
    .read = tis_module_read,
    .open = tis_module_open,
    .release = tis_module_release,
};

static int __init tis_module_init(void)
{
    int ret;
    // 申请dev id
#if (DEV_ID_STATIC)
    dev_info.dev_id = MKDEV(DEV_ID_MAJOR, DEV_ID_MINOR);
    ret = register_chrdev_region(dev_info.dev_id, 1, dev_name);
    if (ret < 0)
    {
        printk("[%s] dev_id get failed\n",dev_name);
        return ret;
    }
#else
    ret = alloc_chrdev_region(&dev_info.dev_id, 0, 1, dev_name);
    if (ret)
    {
        printk("[%s] dev_id get failed\n");
        return ret;
    }
#endif
    // 注册设备
    dev_info.cdev.owner = THIS_MODULE;
    cdev_init(&dev_info.cdev, &tis_module_f);
    ret = cdev_add(&dev_info.cdev, dev_info.dev_id, 1);
    if (ret < 0)
    {
        printk("[%s] cdev_add failed\n", dev_name);
        goto del_unregister;
    }
    // 创建设备
    dev_info.class = class_create(THIS_MODULE, dev_name);
    if (IS_ERR(dev_info.class))
    {
        printk("[%s] class create failed\n", dev_name);
        goto del_cdev;
    }
    dev_info.device = device_create(dev_info.class, NULL, dev_info.dev_id, NULL, dev_name);
    if (IS_ERR(dev_info.device))
    {
        printk("[%s] dev create failed\n", dev_name);
        goto destroy_class;
    }
    printk("[%s] init success\n", dev_name);
    return 0;

destroy_class:
    class_destroy(dev_info.class);
del_cdev:
    cdev_del(&dev_info.cdev);
del_unregister:
    unregister_chrdev_region(dev_info.dev_id, 1);
    return -EIO;
}
static void __exit tis_module_exit(void)
{
    /* 注销字符设备驱动 */
    cdev_del(&dev_info.cdev);                     /*  删除cdev */
    unregister_chrdev_region(dev_info.dev_id, 1); /* 注销设备号 */
    device_destroy(dev_info.class, dev_info.dev_id);
    class_destroy(dev_info.class);
    printk("[%s] exit success\n", dev_name);
}
module_init(tis_module_init);
module_exit(tis_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("chenyf");
MODULE_INFO(intree, "Y");