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static struct bus_type gpio_bus_type = { .name = "gpio",};

static int __init gpiolib_dev_init(void){ int ret;  /* Register GPIO sysfs bus */ ret  = bus_register(&gpio_bus_type); if (ret < 0) {  pr_err("gpiolib: could not register GPIO bus type\n");  return ret; }  ret = alloc_chrdev_region(&gpio_devt, 0, GPIO_DEV_MAX, "gpiochip"); if (ret < 0) {  pr_err("gpiolib: failed to allocate char dev region\n");  bus_unregister(&gpio_bus_type); } else {  gpiolib_initialized = true;  gpiochip_setup_devs(); } return ret;}core_initcall(gpiolib_dev_init);

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