int lg4ff_init(struct hid_device *hid)
{
	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
	struct input_dev *dev = hidinput->input;
	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
	const struct usb_device_descriptor *udesc = &(hid_to_usb_dev(hid)->descriptor);
	const u16 bcdDevice = le16_to_cpu(udesc->bcdDevice);
	const struct lg4ff_multimode_wheel *mmode_wheel = NULL;
	struct lg4ff_device_entry *entry;
	struct lg_drv_data *drv_data;
	int error, i, j;
	int mmode_ret, mmode_idx = -1;
	u16 real_product_id;

	/* Check that the report looks ok */
	if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 7))
		return -1;

	drv_data = hid_get_drvdata(hid);
	if (!drv_data) {
		hid_err(hid, "Cannot add device, private driver data not allocated\n");
		return -1;
	}
	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return -ENOMEM;
	spin_lock_init(&entry->report_lock);
	entry->report = report;
	drv_data->device_props = entry;

	/* Check if a multimode wheel has been connected and
	 * handle it appropriately */
	mmode_ret = lg4ff_handle_multimode_wheel(hid, &real_product_id, bcdDevice);

	/* Wheel has been told to switch to native mode. There is no point in going on
	 * with the initialization as the wheel will do a USB reset when it switches mode
	 */
	if (mmode_ret == LG4FF_MMODE_SWITCHED)
		return 0;
	else if (mmode_ret < 0) {
		hid_err(hid, "Unable to switch device mode during initialization, errno %d\n", mmode_ret);
		error = mmode_ret;
		goto err_init;
	}

	/* Check what wheel has been connected */
	for (i = 0; i < ARRAY_SIZE(lg4ff_devices); i++) {
		if (hid->product == lg4ff_devices[i].product_id) {
			dbg_hid("Found compatible device, product ID %04X\n", lg4ff_devices[i].product_id);
			break;
		}
	}

	if (i == ARRAY_SIZE(lg4ff_devices)) {
		hid_err(hid, "This device is flagged to be handled by the lg4ff module but this module does not know how to handle it. "
			     "Please report this as a bug to LKML, Simon Wood <simon@mungewell.org> or "
			     "Michal Maly <madcatxster@devoid-pointer.net>\n");
		error = -1;
		goto err_init;
	}

	if (mmode_ret == LG4FF_MMODE_IS_MULTIMODE) {
		for (mmode_idx = 0; mmode_idx < ARRAY_SIZE(lg4ff_multimode_wheels); mmode_idx++) {
			if (real_product_id == lg4ff_multimode_wheels[mmode_idx].product_id)
				break;
		}

		if (mmode_idx == ARRAY_SIZE(lg4ff_multimode_wheels)) {
			hid_err(hid, "Device product ID %X is not listed as a multimode wheel", real_product_id);
			error = -1;
			goto err_init;
		}
	}

	/* Set supported force feedback capabilities */
	for (j = 0; lg4ff_devices[i].ff_effects[j] >= 0; j++)
		set_bit(lg4ff_devices[i].ff_effects[j], dev->ffbit);

	error = input_ff_create_memless(dev, NULL, lg4ff_play);

	if (error)
		goto err_init;

	/* Initialize device properties */
	if (mmode_ret == LG4FF_MMODE_IS_MULTIMODE) {
		BUG_ON(mmode_idx == -1);
		mmode_wheel = &lg4ff_multimode_wheels[mmode_idx];
	}
	lg4ff_init_wheel_data(&entry->wdata, &lg4ff_devices[i], mmode_wheel, real_product_id);

	/* Check if autocentering is available and
	 * set the centering force to zero by default */
	if (test_bit(FF_AUTOCENTER, dev->ffbit)) {
		/* Formula Force EX expects different autocentering command */
		if ((bcdDevice >> 8) == LG4FF_FFEX_REV_MAJ &&
		    (bcdDevice & 0xff) == LG4FF_FFEX_REV_MIN)
			dev->ff->set_autocenter = lg4ff_set_autocenter_ffex;
		else
			dev->ff->set_autocenter = lg4ff_set_autocenter_default;

		dev->ff->set_autocenter(dev, 0);
	}

	/* Create sysfs interface */
	error = device_create_file(&hid->dev, &dev_attr_combine_pedals);
	if (error)
		hid_warn(hid, "Unable to create sysfs interface for \"combine\", errno %d\n", error);
	error = device_create_file(&hid->dev, &dev_attr_range);
	if (error)
		hid_warn(hid, "Unable to create sysfs interface for \"range\", errno %d\n", error);
	if (mmode_ret == LG4FF_MMODE_IS_MULTIMODE) {
		error = device_create_file(&hid->dev, &dev_attr_real_id);
		if (error)
			hid_warn(hid, "Unable to create sysfs interface for \"real_id\", errno %d\n", error);
		error = device_create_file(&hid->dev, &dev_attr_alternate_modes);
		if (error)
			hid_warn(hid, "Unable to create sysfs interface for \"alternate_modes\", errno %d\n", error);
	}
	dbg_hid("sysfs interface created\n");

	/* Set the maximum range to start with */
	entry->wdata.range = entry->wdata.max_range;
	if (entry->wdata.set_range)
		entry->wdata.set_range(hid, entry->wdata.range);

#ifdef CONFIG_LEDS_CLASS
	/* register led subsystem - G27/G29 only */
	entry->wdata.led_state = 0;
	for (j = 0; j < 5; j++)
		entry->wdata.led[j] = NULL;

	if (lg4ff_devices[i].product_id == USB_DEVICE_ID_LOGITECH_G27_WHEEL ||
			lg4ff_devices[i].product_id == USB_DEVICE_ID_LOGITECH_G29_WHEEL) {
		struct led_classdev *led;
		size_t name_sz;
		char *name;

		lg4ff_set_leds(hid, 0);

		name_sz = strlen(dev_name(&hid->dev)) + 8;

		for (j = 0; j < 5; j++) {
			led = kzalloc(sizeof(struct led_classdev)+name_sz, GFP_KERNEL);
			if (!led) {
				hid_err(hid, "can't allocate memory for LED %d\n", j);
				goto err_leds;
			}

			name = (void *)(&led[1]);
			snprintf(name, name_sz, "%s::RPM%d", dev_name(&hid->dev), j+1);
			led->name = name;
			led->brightness = 0;
			led->max_brightness = 1;
			led->brightness_get = lg4ff_led_get_brightness;
			led->brightness_set = lg4ff_led_set_brightness;

			entry->wdata.led[j] = led;
			error = led_classdev_register(&hid->dev, led);

			if (error) {
				hid_err(hid, "failed to register LED %d. Aborting.\n", j);
err_leds:
				/* Deregister LEDs (if any) */
				for (j = 0; j < 5; j++) {
					led = entry->wdata.led[j];
					entry->wdata.led[j] = NULL;
					if (!led)
						continue;
					led_classdev_unregister(led);
					kfree(led);
				}
				goto out;	/* Let the driver continue without LEDs */
			}
		}
	}
out:
#endif
	hid_info(hid, "Force feedback support for Logitech Gaming Wheels\n");
	return 0;

err_init:
	drv_data->device_props = NULL;
	kfree(entry);
	return error;
}
Unknown