static ssize_t show_brightness(struct device *dev, char *buf)
static ssize_t show_brightness(struct device *dev, struct device_attribute *attr, char *buf)
static ssize_t show_brightness(struct device *dev, char *buf){	struct usb_interface *intf = to_usb_interface(dev);    	struct usb_cytherm *cytherm = usb_get_intfdata(intf);     	return sprintf(buf, "%i", cytherm->brightness);}