linux内核下 UART 键盘驱动代码

这里是一个Linux内核下UART键盘驱动的代码示例：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/input.h>
#include <linux/serio.h>

#define KEYBOARD_NAME "MyKeyboard"
#define KEYBOARD_PHYS "mykeyboard/input0"

static struct serio *serio;

static int mykeyboard_connect(struct serio *serio, struct serio_driver *drv)
{
    int err;

    printk(KERN_INFO "MyKeyboard: Connecting to serio...\n");

    // 初始化键盘
    err = serio_open(serio, drv);
    if (err) {
        printk(KERN_ERR "MyKeyboard: Failed to open serio: %d\n", err);
        return err;
    }

    // 注册输入设备
    err = input_register_device(input_dev);
    if (err) {
        printk(KERN_ERR "MyKeyboard: Failed to register input device: %d\n", err);
        serio_close(serio);
        return err;
    }

    printk(KERN_INFO "MyKeyboard: Keyboard successfully connected\n");

    return 0;
}

static void mykeyboard_disconnect(struct serio *serio)
{
    printk(KERN_INFO "MyKeyboard: Disconnecting from serio...\n");

    // 取消注册输入设备
    input_unregister_device(input_dev);

    // 关闭键盘
    serio_close(serio);

    printk(KERN_INFO "MyKeyboard: Keyboard successfully disconnected\n");
}

static const struct serio_device_id mykeyboard_serio_ids[] = {
    {
        .type = SERIO_RS232,
        .proto = SERIO_PROTO_KEYBOARD,
        .id = SERIO_ANY_ID,
        .extra = SERIO_ANY_EXTRA,
    },
    { }
};
MODULE_DEVICE_TABLE(serio, mykeyboard_serio_ids);

static struct serio_driver mykeyboard_drv = {
    .driver = {
        .name = KEYBOARD_NAME,
        .owner = THIS_MODULE,
    },
    .description = "My Keyboard Driver",
    .id_table = mykeyboard_serio_ids,
    .connect = mykeyboard_connect,
    .disconnect = mykeyboard_disconnect,
};

static int __init mykeyboard_init(void)
{
    int err;

    // 分配输入设备结构体
    input_dev = input_allocate_device();
    if (!input_dev) {
        printk(KERN_ERR "MyKeyboard: Failed to allocate input device\n");
        return -ENOMEM;
    }

    // 设置输入设备的属性
    input_dev->name = KEYBOARD_NAME;
    input_dev->phys = KEYBOARD_PHYS;
    input_dev->id.bustype = BUS_RS232;

    // 设置输入事件
    input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
    input_dev->keybit[BIT_WORD(KEY_ESC)] = BIT_MASK(KEY_ESC);

    // 注册serio驱动
    err = serio_register_driver(&mykeyboard_drv);
    if (err) {
        printk(KERN_ERR "MyKeyboard: Failed to register serio driver: %d\n", err);
        input_free_device(input_dev);
        return err;
    }

    printk(KERN_INFO "MyKeyboard: Driver successfully loaded\n");

    return 0;
}

static void __exit mykeyboard_exit(void)
{
    serio_unregister_driver(&mykeyboard_drv);
    input_free_device(input_dev);

    printk(KERN_INFO "MyKeyboard: Driver successfully unloaded\n");
}

module_init(mykeyboard_init);
module_exit(mykeyboard_exit);

MODULE_AUTHOR("Your Name Here");
MODULE_DESCRIPTION("My Keyboard Driver");
MODULE_LICENSE("GPL");

这个驱动使用了Serio子系统来与UART接口通信，并将键盘识别为一个输入设备。在键盘被连接时，将初始化输入设备并注册到输入子系统；当键盘被断开时，将取消注册输入设备并关闭Serio接口。在本例中，键盘只支持一个键（ESC键），但您可以添加更多的键和事件。