如果有三个I2C设备，如下所述，在设备驱动程序init（）函数中调用以下调用register_chrdev（89，“i2c”，&i2cfops）。注意，名称是“i2c”而不是“i2c-0”/“i2c-1”/“i2c-2”。在i2cdriver_open或i2cdriver_ioctl函数中，驱动器如何知道次要编号或为哪个I2C设备调用了该函数？
请参阅下文了解更多详情。

crw-r--r--    1 0        0         89,   0 Jun 12 09:15 /dev/i2c-0
crw-r--r--    1 0        0         89,   1 Jun 12 09:15 /dev/i2c-1
crw-r--r--    1 0        0         89,   2 Jun 12 09:15 /dev/i2c-2

字符串
适用范围：

int main(void)
{
  int fd;
  fd = open("/dev/i2c-0");
  (void) ioctl(fd, ...);
  return 0;
}

型
司机：

static struct file_operations i2cfops;
int i2cdriver_open(struct inode * inodePtr, struct file * filePtr);
int i2cdriver_ioctl(struct inode * inodePtr, struct file * filePtr, unsigned int ui, unsigned long ul);
int driver_init(void)
{
  i2cfops.open = &i2cdriver_open;
  i2cfops.ioctl = &i2cdriver_ioctl;
  (void) register_chrdev(89, "i2c", &i2cfops);
  return 0;
}
int i2cdriver_open(struct inode * inodePtr, struct file * filePtr)
{
  /*In here, how to know the minor number or for which I2C device this function has been invoked?*/
}
int i2cdriver_ioctl(struct inode * inodePtr, struct file * filePtr, unsigned int ui, unsigned long ul)
{
  /*In here, how to know the minor number or for which I2C device this function has been invoked?*/
}

型