static int nintendo_hid_probe()

in hid-nintendo.c [2107:2277]

• 119 lines of code
• 20 McCabe index (conditional complexity)

static int nintendo_hid_probe(struct hid_device *hdev,
			    const struct hid_device_id *id)
{
	int ret;
	struct joycon_ctlr *ctlr;

	hid_dbg(hdev, "probe - start\n");

	ctlr = devm_kzalloc(&hdev->dev, sizeof(*ctlr), GFP_KERNEL);
	if (!ctlr) {
		ret = -ENOMEM;
		goto err;
	}

	ctlr->hdev = hdev;
	ctlr->ctlr_state = JOYCON_CTLR_STATE_INIT;
	ctlr->rumble_queue_head = JC_RUMBLE_QUEUE_SIZE - 1;
	ctlr->rumble_queue_tail = 0;
	hid_set_drvdata(hdev, ctlr);
	mutex_init(&ctlr->output_mutex);
	init_waitqueue_head(&ctlr->wait);
	spin_lock_init(&ctlr->lock);
	ctlr->rumble_queue = alloc_workqueue("hid-nintendo-rumble_wq",
					     WQ_FREEZABLE | WQ_MEM_RECLAIM, 0);
	INIT_WORK(&ctlr->rumble_worker, joycon_rumble_worker);

	ret = hid_parse(hdev);
	if (ret) {
		hid_err(hdev, "HID parse failed\n");
		goto err_wq;
	}

	/*
	 * Patch the hw version of pro controller/joycons, so applications can
	 * distinguish between the default HID mappings and the mappings defined
	 * by the Linux game controller spec. This is important for the SDL2
	 * library, which has a game controller database, which uses device ids
	 * in combination with version as a key.
	 */
	hdev->version |= 0x8000;

	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
	if (ret) {
		hid_err(hdev, "HW start failed\n");
		goto err_wq;
	}

	ret = hid_hw_open(hdev);
	if (ret) {
		hid_err(hdev, "cannot start hardware I/O\n");
		goto err_stop;
	}

	hid_device_io_start(hdev);

	/* Initialize the controller */
	mutex_lock(&ctlr->output_mutex);
	/* if handshake command fails, assume ble pro controller */
	if ((jc_type_is_procon(ctlr) || jc_type_is_chrggrip(ctlr)) &&
	    !joycon_send_usb(ctlr, JC_USB_CMD_HANDSHAKE, HZ)) {
		hid_dbg(hdev, "detected USB controller\n");
		/* set baudrate for improved latency */
		ret = joycon_send_usb(ctlr, JC_USB_CMD_BAUDRATE_3M, HZ);
		if (ret) {
			hid_err(hdev, "Failed to set baudrate; ret=%d\n", ret);
			goto err_mutex;
		}
		/* handshake */
		ret = joycon_send_usb(ctlr, JC_USB_CMD_HANDSHAKE, HZ);
		if (ret) {
			hid_err(hdev, "Failed handshake; ret=%d\n", ret);
			goto err_mutex;
		}
		/*
		 * Set no timeout (to keep controller in USB mode).
		 * This doesn't send a response, so ignore the timeout.
		 */
		joycon_send_usb(ctlr, JC_USB_CMD_NO_TIMEOUT, HZ/10);
	} else if (jc_type_is_chrggrip(ctlr)) {
		hid_err(hdev, "Failed charging grip handshake\n");
		ret = -ETIMEDOUT;
		goto err_mutex;
	}

	/* get controller calibration data, and parse it */
	ret = joycon_request_calibration(ctlr);
	if (ret) {
		/*
		 * We can function with default calibration, but it may be
		 * inaccurate. Provide a warning, and continue on.
		 */
		hid_warn(hdev, "Analog stick positions may be inaccurate\n");
	}

	/* get IMU calibration data, and parse it */
	ret = joycon_request_imu_calibration(ctlr);
	if (ret) {
		/*
		 * We can function with default calibration, but it may be
		 * inaccurate. Provide a warning, and continue on.
		 */
		hid_warn(hdev, "Unable to read IMU calibration data\n");
	}

	/* Set the reporting mode to 0x30, which is the full report mode */
	ret = joycon_set_report_mode(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to set report mode; ret=%d\n", ret);
		goto err_mutex;
	}

	/* Enable rumble */
	ret = joycon_enable_rumble(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to enable rumble; ret=%d\n", ret);
		goto err_mutex;
	}

	/* Enable the IMU */
	ret = joycon_enable_imu(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to enable the IMU; ret=%d\n", ret);
		goto err_mutex;
	}

	ret = joycon_read_info(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to retrieve controller info; ret=%d\n",
			ret);
		goto err_mutex;
	}

	mutex_unlock(&ctlr->output_mutex);

	/* Initialize the leds */
	ret = joycon_leds_create(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to create leds; ret=%d\n", ret);
		goto err_close;
	}

	/* Initialize the battery power supply */
	ret = joycon_power_supply_create(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to create power_supply; ret=%d\n", ret);
		goto err_close;
	}

	ret = joycon_input_create(ctlr);
	if (ret) {
		hid_err(hdev, "Failed to create input device; ret=%d\n", ret);
		goto err_close;
	}

	ctlr->ctlr_state = JOYCON_CTLR_STATE_READ;

	hid_dbg(hdev, "probe - success\n");
	return 0;

err_mutex:
	mutex_unlock(&ctlr->output_mutex);
err_close:
	hid_hw_close(hdev);
err_stop:
	hid_hw_stop(hdev);
err_wq:
	destroy_workqueue(ctlr->rumble_queue);
err:
	hid_err(hdev, "probe - fail = %d\n", ret);
	return ret;
}