Linux下tty驱动框架

在Linux下编写串口驱动程序，需要使用Linux提供的tty和serial驱动模块。以下是一个简单的tty串口驱动程序示例，使用C语言编写：

#include <linux/module.h>
#include <linux/serial_core.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>

static struct tty_driver *my_serial_tty_driver;

// 初始化串口
static int my_serial_init(struct tty_struct* tty)
{
    printk(KERN_INFO "my_serial_init called\n");
    return 0;
}

// 打开串口
static int my_serial_open(struct tty_struct* tty, struct file* filp)
{
    printk(KERN_INFO "my_serial_open called\n");
    return 0;
}

// 从串口读取数据
static ssize_t my_serial_read(struct tty_struct* tty, struct file* filp,
                              unsigned char* buf, size_t count)
{
    printk(KERN_INFO "my_serial_read called\n");
    return 0;
}

// 向串口发送数据
static ssize_t my_serial_write(struct tty_struct* tty, struct file* filp,
                               const unsigned char* buf, size_t count)
{
    printk(KERN_INFO "my_serial_write called\n");
    return 0;
}

// 关闭串口
static void my_serial_close(struct tty_struct* tty, struct file* filp)
{
    printk(KERN_INFO "my_serial_close called\n");
}

// 设置串口属性
static int my_serial_set_param(struct tty_struct* tty, struct ktermios* old_termios)
{
    printk(KERN_INFO "my_serial_set_param called\n");
    return 0;
}

// 驱动程序结构体
static struct tty_operations my_serial_tty_ops = {
    .open = my_serial_open,
    .close = my_serial_close,
    .read = my_serial_read,
    .write = my_serial_write,
    .set_termios = my_serial_set_param,
    .init_termios = my_serial_init
};

// 初始化驱动程序
static int __init my_serial_init_driver(void)
{
    // 注册tty驱动
    my_serial_tty_driver = alloc_tty_driver(1);
    if (!my_serial_tty_driver) {
        printk(KERN_ERR "Failed to allocate tty driver\n");
        return -ENOMEM;
    }

    my_serial_tty_driver->owner = THIS_MODULE;
    my_serial_tty_driver->driver_name = "my_serial";
    my_serial_tty_driver->name = "ttyMySerial";
    my_serial_tty_driver->major = 0; // 使用动态分配的主设备号
    my_serial_tty_driver->minor_start = 0;
    my_serial_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
    my_serial_tty_driver->subtype = SERIAL_TYPE_NORMAL;
    tty_set_operations(my_serial_tty_driver, &my_serial_tty_ops);

    // 注册tty设备
    if (tty_register_driver(my_serial_tty_driver)) {
        printk(KERN_ERR "Failed to register tty driver\n");
        put_tty_driver(my_serial_tty_driver);
        return -EINVAL;
    }

    printk(KERN_INFO "my_serial driver initialized successfully\n");
    return 0;
}

// 卸载驱动程序
static void __exit my_serial_exit_driver(void)
{
    tty_unregister_driver(my_serial_tty_driver);
    put_tty_driver(my_serial_tty_driver);
    printk(KERN_INFO "my_serial driver unregistered\n");
}

module_init(my_serial_init_driver);
module_exit(my_serial_exit_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("Sample serial driver");

在此示例中，我们使用了Linux提供的serial_core.h和tty.h头文件。串口驱动程序的主要函数包括初始化、打开、读取、写入、关闭和设置属性。