static int usb_pcwd_probe()

in pcwd_usb.c [599:758]

• 113 lines of code
• 19 McCabe index (conditional complexity)

static int usb_pcwd_probe(struct usb_interface *interface,
						const struct usb_device_id *id)
{
	struct usb_device *udev = interface_to_usbdev(interface);
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	struct usb_pcwd_private *usb_pcwd = NULL;
	int pipe;
	int retval = -ENOMEM;
	int got_fw_rev;
	unsigned char fw_rev_major, fw_rev_minor;
	char fw_ver_str[20];
	unsigned char option_switches, dummy;

	cards_found++;
	if (cards_found > 1) {
		pr_err("This driver only supports 1 device\n");
		return -ENODEV;
	}

	/* get the active interface descriptor */
	iface_desc = interface->cur_altsetting;

	/* check out that we have a HID device */
	if (!(iface_desc->desc.bInterfaceClass == USB_CLASS_HID)) {
		pr_err("The device isn't a Human Interface Device\n");
		return -ENODEV;
	}

	if (iface_desc->desc.bNumEndpoints < 1)
		return -ENODEV;

	/* check out the endpoint: it has to be Interrupt & IN */
	endpoint = &iface_desc->endpoint[0].desc;

	if (!usb_endpoint_is_int_in(endpoint)) {
		/* we didn't find a Interrupt endpoint with direction IN */
		pr_err("Couldn't find an INTR & IN endpoint\n");
		return -ENODEV;
	}

	/* get a handle to the interrupt data pipe */
	pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);

	/* allocate memory for our device and initialize it */
	usb_pcwd = kzalloc(sizeof(struct usb_pcwd_private), GFP_KERNEL);
	if (usb_pcwd == NULL)
		goto error;

	usb_pcwd_device = usb_pcwd;

	mutex_init(&usb_pcwd->mtx);
	usb_pcwd->udev = udev;
	usb_pcwd->interface = interface;
	usb_pcwd->interface_number = iface_desc->desc.bInterfaceNumber;
	usb_pcwd->intr_size = (le16_to_cpu(endpoint->wMaxPacketSize) > 8 ?
				le16_to_cpu(endpoint->wMaxPacketSize) : 8);

	/* set up the memory buffer's */
	usb_pcwd->intr_buffer = usb_alloc_coherent(udev, usb_pcwd->intr_size,
					GFP_KERNEL, &usb_pcwd->intr_dma);
	if (!usb_pcwd->intr_buffer) {
		pr_err("Out of memory\n");
		goto error;
	}

	/* allocate the urb's */
	usb_pcwd->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!usb_pcwd->intr_urb)
		goto error;

	/* initialise the intr urb's */
	usb_fill_int_urb(usb_pcwd->intr_urb, udev, pipe,
			usb_pcwd->intr_buffer, usb_pcwd->intr_size,
			usb_pcwd_intr_done, usb_pcwd, endpoint->bInterval);
	usb_pcwd->intr_urb->transfer_dma = usb_pcwd->intr_dma;
	usb_pcwd->intr_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	/* register our interrupt URB with the USB system */
	if (usb_submit_urb(usb_pcwd->intr_urb, GFP_KERNEL)) {
		pr_err("Problem registering interrupt URB\n");
		retval = -EIO; /* failure */
		goto error;
	}

	/* The device exists and can be communicated with */
	usb_pcwd->exists = 1;

	/* disable card */
	usb_pcwd_stop(usb_pcwd);

	/* Get the Firmware Version */
	got_fw_rev = usb_pcwd_send_command(usb_pcwd, CMD_GET_FIRMWARE_VERSION,
						&fw_rev_major, &fw_rev_minor);
	if (got_fw_rev)
		sprintf(fw_ver_str, "%u.%02u", fw_rev_major, fw_rev_minor);
	else
		sprintf(fw_ver_str, "<card no answer>");

	pr_info("Found card (Firmware: %s) with temp option\n", fw_ver_str);

	/* Get switch settings */
	usb_pcwd_send_command(usb_pcwd, CMD_GET_DIP_SWITCH_SETTINGS, &dummy,
							&option_switches);

	pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
		option_switches,
		((option_switches & 0x10) ? "ON" : "OFF"),
		((option_switches & 0x08) ? "ON" : "OFF"));

	/* If heartbeat = 0 then we use the heartbeat from the dip-switches */
	if (heartbeat == 0)
		heartbeat = heartbeat_tbl[(option_switches & 0x07)];

	/* Check that the heartbeat value is within it's range ;
	 * if not reset to the default */
	if (usb_pcwd_set_heartbeat(usb_pcwd, heartbeat)) {
		usb_pcwd_set_heartbeat(usb_pcwd, WATCHDOG_HEARTBEAT);
		pr_info("heartbeat value must be 0<heartbeat<65536, using %d\n",
			WATCHDOG_HEARTBEAT);
	}

	retval = register_reboot_notifier(&usb_pcwd_notifier);
	if (retval != 0) {
		pr_err("cannot register reboot notifier (err=%d)\n", retval);
		goto error;
	}

	retval = misc_register(&usb_pcwd_temperature_miscdev);
	if (retval != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       TEMP_MINOR, retval);
		goto err_out_unregister_reboot;
	}

	retval = misc_register(&usb_pcwd_miscdev);
	if (retval != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, retval);
		goto err_out_misc_deregister;
	}

	/* we can register the device now, as it is ready */
	usb_set_intfdata(interface, usb_pcwd);

	pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
		heartbeat, nowayout);

	return 0;

err_out_misc_deregister:
	misc_deregister(&usb_pcwd_temperature_miscdev);
err_out_unregister_reboot:
	unregister_reboot_notifier(&usb_pcwd_notifier);
error:
	if (usb_pcwd)
		usb_pcwd_delete(usb_pcwd);
	usb_pcwd_device = NULL;
	return retval;
}