给找一个嵌入式linux下mips使用io口模拟spi的驱动代码要求1Mhz

以下是一个简单的嵌入式linux下mips使用io口模拟spi的驱动代码，实现时钟频率为1MHz：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

static int spi_major = 0;
static int spi_minor = 0;
static int spi_count = 1;
static dev_t spi_dev;
static struct cdev spi_cdev;
static struct class *spi_class = NULL;
static struct device *spi_device = NULL;

static volatile unsigned long *io_reg = NULL;

// SPI时序参数
#define SPI_CLK_PERIOD_NS 1000   // 时钟周期1us

static int spi_open(struct inode *inode, struct file *filp)
{
    return 0;
}

static int spi_release(struct inode *inode, struct file *filp)
{
    return 0;
}

static ssize_t spi_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
    return 0;
}

static ssize_t spi_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos)
{
    unsigned char *data;
    unsigned int i;

    data = kmalloc(count, GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    if (copy_from_user(data, buf, count)) {
        kfree(data);
        return -EFAULT;
    }

    // 模拟SPI传输
    for (i = 0; i < count; i++) {
        unsigned char byte = data[i];
        int j;

        // 发送数据
        for (j = 7; j >= 0; j--) {
            int bit = (byte >> j) & 0x01;
            *io_reg &= ~(1 << 0);   // 设置SDI引脚为低电平
            *io_reg &= ~(1 << 1);   // 设置SCK引脚为低电平
            *io_reg |= (bit << 0);  // 设置SDI引脚
            *io_reg |= (1 << 1);    // 设置SCK引脚为高电平
            *io_reg &= ~(1 << 1);   // 设置SCK引脚为低电平
        }

        // 接收数据
        byte = 0;
        for (j = 7; j >= 0; j--) {
            *io_reg &= ~(1 << 1);   // 设置SCK引脚为低电平
            byte |= ((*io_reg >> 2) & 0x01) << j;   // 读取SDO引脚数据
            *io_reg |= (1 << 1);    // 设置SCK引脚为高电平
        }
        printk(KERN_INFO "spi_write: %02x\n", byte);
    }

    kfree(data);
    return count;
}

static struct file_operations spi_fops = {
    .owner = THIS_MODULE,
    .read = spi_read,
    .write = spi_write,
    .open = spi_open,
    .release = spi_release,
};

static int __init spi_init(void)
{
    int ret;

    // 分配设备号
    if (spi_major) {
        spi_dev = MKDEV(spi_major, spi_minor);
        ret = register_chrdev_region(spi_dev, spi_count, "spi");
    } else {
        ret = alloc_chrdev_region(&spi_dev, spi_minor, spi_count, "spi");
        spi_major = MAJOR(spi_dev);
    }
    if (ret < 0) {
        printk(KERN_ERR "spi: unable to allocate major number\n");
        return ret;
    }

    // 创建设备类
    spi_class = class_create(THIS_MODULE, "spi");
    if (IS_ERR(spi_class)) {
        printk(KERN_ERR "spi: failed to create device class\n");
        unregister_chrdev_region(spi_dev, spi_count);
        return PTR_ERR(spi_class);
    }

    // 创建设备节点
    spi_device = device_create(spi_class, NULL, spi_dev, NULL, "spi");
    if (IS_ERR(spi_device)) {
        printk(KERN_ERR "spi: failed to create device node\n");
        class_destroy(spi_class);
        unregister_chrdev_region(spi_dev, spi_count);
        return PTR_ERR(spi_device);
    }

    // 初始化字符设备
    cdev_init(&spi_cdev, &spi_fops);
    spi_cdev.owner = THIS_MODULE;

    // 注册字符设备
    ret = cdev_add(&spi_cdev, spi_dev, spi_count);
    if (ret < 0) {
        printk(KERN_ERR "spi: failed to add char device\n");
        device_destroy(spi_class, spi_dev);
        class_destroy(spi_class);
        unregister_chrdev_region(spi_dev, spi_count);
        return ret;
    }

    // 映射GPIO控制寄存器
    io_reg = ioremap(0x80000000, 0x1000);

    return 0;
}

static void __exit spi_exit(void)
{
    // 解除映射
    iounmap(io_reg);

    // 注销字符设备
    cdev_del(&spi_cdev);

    // 销毁设备节点和设备类
    device_destroy(spi_class, spi_dev);
    class_destroy(spi_class);

    // 释放设备号
    unregister_chrdev_region(spi_dev, spi_count);
}

module_init(spi_init);
module_exit(spi_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("SPI driver for MIPS")