写一段嵌入式Linux串口驱动代码

以下是一个简单的嵌入式Linux串口驱动代码示例：

#include <linux/module.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/tty.h>

static struct uart_driver my_uart_driver = {
    .owner = THIS_MODULE,
    .driver_name = "my_uart_driver",
    .dev_name = "ttyMY",
    .major = TTY_MAJOR,
    .minor = 0,
    .nr = 1,
};

static int my_uart_probe(struct platform_device *pdev)
{
    struct uart_port *port;
    int ret;

    port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
    if (!port)
        return -ENOMEM;

    uart_unregister_driver(&my_uart_driver);

    uart_port_init(port);
    port->iotype = UPIO_MEM;
    port->flags = UPF_BOOT_AUTOCONF;
    port->ops = &my_uart_ops;
    port->line = my_uart_driver.minor;
    port->irq = pdev->irq;

    ret = uart_add_one_port(&my_uart_driver, port);
    if (ret < 0) {
        kfree(port);
        return ret;
    }

    platform_set_drvdata(pdev, port);

    return 0;
}

static int my_uart_remove(struct platform_device *pdev)
{
    struct uart_port *port = dev_get_drvdata(&pdev->dev);

    uart_remove_one_port(&my_uart_driver, port);
    kfree(port);

    return 0;
}

static struct platform_driver my_uart_platform_driver = {
    .probe = my_uart_probe,
    .remove = my_uart_remove,
    .driver = {
        .name = "my_uart",
        .owner = THIS_MODULE,
    },
};

static int __init my_uart_init(void)
{
    int ret;

    ret = uart_register_driver(&my_uart_driver);
    if (ret < 0)
        return ret;

    ret = platform_driver_register(&my_uart_platform_driver);
    if (ret < 0) {
        uart_unregister_driver(&my_uart_driver);
        return ret;
    }

    return 0;
}

static void __exit my_uart_exit(void)
{
    platform_driver_unregister(&my_uart_platform_driver);
    uart_unregister_driver(&my_uart_driver);
}

module_init(my_uart_init);
module_exit(my_uart_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your name");
MODULE_DESCRIPTION("My UART driver");

这个例子中，我们定义了一个名为"my_uart_driver"的串口驱动程序。在probe函数中，我们初始化了串口端口，分配了内存，并将其添加到串口驱动程序中。在remove函数中，我们从串口驱动中删除端口并释放内存。最后，在init函数中，我们注册了平台驱动程序和串口驱动程序。在exit函数中，我们注销了平台驱动程序和串口驱动程序。