2.6内核IIC驱动程序源码（2）（转载）

struct IIC_dev{
        wait_queue_head_t rq; // 读取等待队列
        uint8_t *buffer;
        uint32_t size;
        uint32_t index;
        struct semaphore sem;
        struct cdev cdev;
};
struct IIC_dev *my_dev;

static int __init IIC_init(void)
{
        // 1. 分配主设备号
        dev_t devno = MKDEV( major, minor );
        int ret = register_chrdev_region( devno, 1, DEVICE );//(设备号，注册号，名称)
        if( ret < 0 )
        {
          printk(KERN_DEBUG "register major number failed with %d\n", ret);
          return ret;
        }
        printk(KERN_DEBUG "%s:register major number OK\n",DEVICE);

        // 2. 注册设备
        my_dev = kmalloc(sizeof(struct IIC_dev), GFP_KERNEL);
        memset( my_dev, 0, sizeof(struct IIC_dev) );
        cdev_init( &my_dev->cdev, &fops );
        my_dev->cdev.ops = &fops;
        my_dev->cdev.owner = THIS_MODULE;
        ret = cdev_add( &my_dev->cdev, devno, 1 );
        if( ret < 0 )
        {
          printk(KERN_DEBUG "register device failed with %d\n", ret);
          return ret;
        }
        printk(KERN_DEBUG "%s:register device OK\n",DEVICE);

        // 3. 分配本驱动要使用的内存
        my_dev->index = 0;
        my_dev->size = 128;
        my_dev->buffer = kmalloc( my_dev->size, GFP_KERNEL );
        if( NULL == my_dev->buffer )
        {
          printk(KERN_DEBUG "kmalloc failed\n");
          return -ENOMEM;
        }
        printk(KERN_DEBUG "%s:kmalloc buffer OK\n",DEVICE);

        // 4. 初始化信号量
        init_MUTEX( &(my_dev->sem) );
        printk(KERN_DEBUG "%s:init semaphore OK\n",DEVICE);

        // 5. 初始化等待队列头
        init_waitqueue_head(&my_dev->rq);

        // 6. Remap IIC 寄存器
        address_map();

        // 7. 设置 s3c2410 IIC
        unsigned int tmp = ioread32( R_GPEUP );
        tmp |= 0xc000; //Pull-up disable
        iowrite32( tmp, R_GPEUP );
        tmp = ioread32( R_GPECON );
        tmp |= 0xa0000000; //GPE15:IICSDA , GPE14:IICSCL
        iowrite32( tmp, R_GPECON );
        return 0;
}


static void __exit IIC_exit(void)
{
        dev_t devno = MKDEV( major, minor );
        // 以相反的顺序清除
        address_unmap();
        kfree( my_dev->buffer );
        cdev_del( &my_dev->cdev );
        kfree( my_dev );
        printk(KERN_DEBUG "%s:kfree OK\n",DEVICE);
        unregister_chrdev_region( devno, 1 );
        printk(KERN_DEBUG "%s:unregister device OK\n",DEVICE);
}

static void set_slave_recv_mode(void)
{
        iowrite8( 0xE2, R_IICCON ); // 使能ACK，使能中断
        iowrite8( 0xAA, R_IICADD ); // 从器件地址
        iowrite8( 0x10, R_IICSTAT); // 设置从器件接收模式
        barrier(); // 强制写入寄存器
}

int IIC_open(struct inode *inode, struct file *file)
{
        struct IIC_dev *dev = container_of(inode->i_cdev, struct IIC_dev, cdev);
        file->private_data = dev;
        if( down_interruptible(&dev->sem) )
                return -ERESTARTSYS;
        set_slave_recv_mode();
        int ret = request_irq( IRQ_IIC, interrupt_handle，SA_INTERRUPT, DEVICE, (void*)dev );
        if( ret )
        {
                printk( KERN_INFO "I2C: can't get assigned irq %d\n", IRQ_IIC );
        }
        return 0;
}