linux内核下 UART 触摸屏驱动代码

这里是一个Linux内核下UART触摸屏驱动的代码示例：

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

#define TOUCHSCREEN_NAME "MyTouchscreen"
#define TOUCHSCREEN_PHYS "mytouchscreen/input0"

static struct serio *serio;

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

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

    // 初始化触摸屏
    err = serio_open(serio, drv);
    if (err) {
        printk(KERN_ERR "MyTouchscreen: 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 "MyTouchscreen: Failed to register input device: %d\n", err);
        serio_close(serio);
        return err;
    }

    printk(KERN_INFO "MyTouchscreen: Touchscreen successfully connected\n");

    return 0;
}

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

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

    // 关闭触摸屏
    serio_close(serio);

    printk(KERN_INFO "MyTouchscreen: Touchscreen successfully disconnected\n");
}

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

static struct serio_driver mytouchscreen_drv = {
    .driver = {
        .name = TOUCHSCREEN_NAME,
        .owner = THIS_MODULE,
    },
    .description = "My Touchscreen Driver",
    .id_table = mytouchscreen_serio_ids,
    .connect = mytouchscreen_connect,
    .disconnect = mytouchscreen_disconnect,
};

static int __init mytouchscreen_init(void)
{
    int err;

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

    // 设置输入设备的属性
    input_dev->name = TOUCHSCREEN_NAME;
    input_dev->phys = TOUCHSCREEN_PHYS;

    // 设置输入事件
    input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
    input_set_abs_params(input_dev, ABS_X, 0, 1023, 0, 0);
    input_set_abs_params(input_dev, ABS_Y, 0, 767, 0, 0);

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

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

    return 0;
}

static void __exit mytouchscreen_exit(void)
{
    serio_unregister_driver(&mytouchscreen_drv);
    input_free_device(input_dev);

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

module_init(mytouchscreen_init);
module_exit(mytouchscreen_exit);

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

这个驱动使用了Serio子系统来与UART接口通信，并将触摸屏识别为一个输入设备。在触摸屏被连接时，将初始化输入设备并注册到输入子系统；当触摸屏被断开时，将取消注册输入设备并关闭Serio接口。