I2C_MINORS
if (adap->nr >= I2C_MINORS) {
res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);