2.6内核IIC驱动程序源码（3）（转载）

int IIC_read(struct file *file, char* buf, size_t count, loff_t *f_pos)
{
        struct IIC_dev *dev = file->private_data;
        size_t val = DATA_LEN;
        while( dev->index < val )
        {
                if( file->f_flags & O_NONBLOCK )
                        return -EAGAIN;
                // 在这里准备睡眠,等待条件为真
                if( wait_event_interruptible(dev->rq, (dev->index >= val)) )
                        return -ERESTARTSYS; // 返回非0表示被信号中断
        }
        if( copy_to_user(buf, dev->buffer, val) )
                return -EFAULT;
        memset( dev->buffer, 0, dev->size );
        dev->index = 0;
        set_slave_recv_mode();
        return val;
}

int IIC_release(struct inode *inode, struct file *file)
{
        struct IIC_dev *dev = file->private_data;
        iowrite8( 0x0, R_IICCON );
        iowrite8( 0x0, R_IICADD );
        iowrite8( 0x0, R_IICSTAT);
        barrier(); // 强制写入寄存器
        memset( dev->buffer, 0, dev->size );
        dev->index = 0;
        free_irq( IRQ_IIC, NULL );
        up(&dev->sem);
        return 0;
}

unsigned int IIC_poll(struct file* file, poll_table* wait)
{
        struct IIC_dev *dev = file->private_data;
        unsigned int mask = 0, val = DATA_LEN;
        poll_wait(file,&dev->rq,wait);
        if( dev->index >= val )
                mask |= POLLIN | POLLRDNORM;
        return mask;
}

irqreturn_t interrupt_handle( int irq, void* dev_id, struct pt_regs* regs )
{
        struct IIC_dev *dev = dev_id;
        int val = DATA_LEN;
        uint8_t ch = ioread8( R_IICDS );
        if( dev->index == 0 && ch == 0xAA )
                goto ret;
        dev->buffer[dev->index++] = ch;
        if( dev->index >= val )
        {
                wake_up_interruptible( &dev->rq );
                // 直接退出 Slave Receiver 模式

                return IRQ_HANDLED;
        }
ret:
        iowrite8( 0xEF, R_IICCON );
        return IRQ_HANDLED;
}

module_init(IIC_init);
module_exit(IIC_exit);

MODULE_AUTHOR("kf701.ye AT gmail.com");
MODULE_DESCRIPTION("Study");
MODULE_SUPPORTED_DEVICE(DEVICE);
MODULE_LICENSE("GPL");