Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1552 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c
new file mode 100644
index 000000000..a881c69b1
--- /dev/null
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -0,0 +1,1552 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * f_printer.c - USB printer function driver
+ *
+ * Copied from drivers/usb/gadget/legacy/printer.c,
+ * which was:
+ *
+ * printer.c -- Printer gadget driver
+ *
+ * Copyright (C) 2003-2005 David Brownell
+ * Copyright (C) 2006 Craig W. Nadler
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/timer.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/moduleparam.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/cdev.h>
+#include <linux/kref.h>
+
+#include <asm/byteorder.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/uaccess.h>
+#include <asm/unaligned.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/g_printer.h>
+
+#include "u_printer.h"
+
+#define PRINTER_MINORS		4
+#define GET_DEVICE_ID		0
+#define GET_PORT_STATUS		1
+#define SOFT_RESET		2
+
+#define DEFAULT_Q_LEN		10 /* same as legacy g_printer gadget */
+
+static int major, minors;
+static struct class *usb_gadget_class;
+static DEFINE_IDA(printer_ida);
+static DEFINE_MUTEX(printer_ida_lock); /* protects access do printer_ida */
+
+/*-------------------------------------------------------------------------*/
+
+struct printer_dev {
+	spinlock_t		lock;		/* lock this structure */
+	/* lock buffer lists during read/write calls */
+	struct mutex		lock_printer_io;
+	struct usb_gadget	*gadget;
+	s8			interface;
+	struct usb_ep		*in_ep, *out_ep;
+	struct kref             kref;
+	struct list_head	rx_reqs;	/* List of free RX structs */
+	struct list_head	rx_reqs_active;	/* List of Active RX xfers */
+	struct list_head	rx_buffers;	/* List of completed xfers */
+	/* wait until there is data to be read. */
+	wait_queue_head_t	rx_wait;
+	struct list_head	tx_reqs;	/* List of free TX structs */
+	struct list_head	tx_reqs_active; /* List of Active TX xfers */
+	/* Wait until there are write buffers available to use. */
+	wait_queue_head_t	tx_wait;
+	/* Wait until all write buffers have been sent. */
+	wait_queue_head_t	tx_flush_wait;
+	struct usb_request	*current_rx_req;
+	size_t			current_rx_bytes;
+	u8			*current_rx_buf;
+	u8			printer_status;
+	u8			reset_printer;
+	int			minor;
+	struct cdev		printer_cdev;
+	u8			printer_cdev_open;
+	wait_queue_head_t	wait;
+	unsigned		q_len;
+	char			**pnp_string;	/* We don't own memory! */
+	struct usb_function	function;
+};
+
+static inline struct printer_dev *func_to_printer(struct usb_function *f)
+{
+	return container_of(f, struct printer_dev, function);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * DESCRIPTORS ... most are static, but strings and (full) configuration
+ * descriptors are built on demand.
+ */
+
+/* holds our biggest descriptor */
+#define USB_DESC_BUFSIZE		256
+#define USB_BUFSIZE			8192
+
+static struct usb_interface_descriptor intf_desc = {
+	.bLength =		sizeof(intf_desc),
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_PRINTER,
+	.bInterfaceSubClass =	1,	/* Printer Sub-Class */
+	.bInterfaceProtocol =	2,	/* Bi-Directional */
+	.iInterface =		0
+};
+
+static struct usb_endpoint_descriptor fs_ep_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK
+};
+
+static struct usb_endpoint_descriptor fs_ep_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK
+};
+
+static struct usb_descriptor_header *fs_printer_function[] = {
+	(struct usb_descriptor_header *) &intf_desc,
+	(struct usb_descriptor_header *) &fs_ep_in_desc,
+	(struct usb_descriptor_header *) &fs_ep_out_desc,
+	NULL
+};
+
+/*
+ * usb 2.0 devices need to expose both high speed and full speed
+ * descriptors, unless they only run at full speed.
+ */
+
+static struct usb_endpoint_descriptor hs_ep_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512)
+};
+
+static struct usb_endpoint_descriptor hs_ep_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512)
+};
+
+static struct usb_descriptor_header *hs_printer_function[] = {
+	(struct usb_descriptor_header *) &intf_desc,
+	(struct usb_descriptor_header *) &hs_ep_in_desc,
+	(struct usb_descriptor_header *) &hs_ep_out_desc,
+	NULL
+};
+
+/*
+ * Added endpoint descriptors for 3.0 devices
+ */
+
+static struct usb_endpoint_descriptor ss_ep_in_desc = {
+	.bLength =              USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =      USB_DT_ENDPOINT,
+	.bmAttributes =         USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =       cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_ep_in_comp_desc = {
+	.bLength =              sizeof(ss_ep_in_comp_desc),
+	.bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
+};
+
+static struct usb_endpoint_descriptor ss_ep_out_desc = {
+	.bLength =              USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =      USB_DT_ENDPOINT,
+	.bmAttributes =         USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =       cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_ep_out_comp_desc = {
+	.bLength =              sizeof(ss_ep_out_comp_desc),
+	.bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
+};
+
+static struct usb_descriptor_header *ss_printer_function[] = {
+	(struct usb_descriptor_header *) &intf_desc,
+	(struct usb_descriptor_header *) &ss_ep_in_desc,
+	(struct usb_descriptor_header *) &ss_ep_in_comp_desc,
+	(struct usb_descriptor_header *) &ss_ep_out_desc,
+	(struct usb_descriptor_header *) &ss_ep_out_comp_desc,
+	NULL
+};
+
+/* maxpacket and other transfer characteristics vary by speed. */
+static inline struct usb_endpoint_descriptor *ep_desc(struct usb_gadget *gadget,
+					struct usb_endpoint_descriptor *fs,
+					struct usb_endpoint_descriptor *hs,
+					struct usb_endpoint_descriptor *ss)
+{
+	switch (gadget->speed) {
+	case USB_SPEED_SUPER:
+		return ss;
+	case USB_SPEED_HIGH:
+		return hs;
+	default:
+		return fs;
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void printer_dev_free(struct kref *kref)
+{
+	struct printer_dev *dev = container_of(kref, struct printer_dev, kref);
+
+	kfree(dev);
+}
+
+static struct usb_request *
+printer_req_alloc(struct usb_ep *ep, unsigned len, gfp_t gfp_flags)
+{
+	struct usb_request	*req;
+
+	req = usb_ep_alloc_request(ep, gfp_flags);
+
+	if (req != NULL) {
+		req->length = len;
+		req->buf = kmalloc(len, gfp_flags);
+		if (req->buf == NULL) {
+			usb_ep_free_request(ep, req);
+			return NULL;
+		}
+	}
+
+	return req;
+}
+
+static void
+printer_req_free(struct usb_ep *ep, struct usb_request *req)
+{
+	if (ep != NULL && req != NULL) {
+		kfree(req->buf);
+		usb_ep_free_request(ep, req);
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void rx_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct printer_dev	*dev = ep->driver_data;
+	int			status = req->status;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	list_del_init(&req->list);	/* Remode from Active List */
+
+	switch (status) {
+
+	/* normal completion */
+	case 0:
+		if (req->actual > 0) {
+			list_add_tail(&req->list, &dev->rx_buffers);
+			DBG(dev, "G_Printer : rx length %d\n", req->actual);
+		} else {
+			list_add(&req->list, &dev->rx_reqs);
+		}
+		break;
+
+	/* software-driven interface shutdown */
+	case -ECONNRESET:		/* unlink */
+	case -ESHUTDOWN:		/* disconnect etc */
+		VDBG(dev, "rx shutdown, code %d\n", status);
+		list_add(&req->list, &dev->rx_reqs);
+		break;
+
+	/* for hardware automagic (such as pxa) */
+	case -ECONNABORTED:		/* endpoint reset */
+		DBG(dev, "rx %s reset\n", ep->name);
+		list_add(&req->list, &dev->rx_reqs);
+		break;
+
+	/* data overrun */
+	case -EOVERFLOW:
+		fallthrough;
+
+	default:
+		DBG(dev, "rx status %d\n", status);
+		list_add(&req->list, &dev->rx_reqs);
+		break;
+	}
+
+	wake_up_interruptible(&dev->rx_wait);
+	spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+static void tx_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct printer_dev	*dev = ep->driver_data;
+
+	switch (req->status) {
+	default:
+		VDBG(dev, "tx err %d\n", req->status);
+		fallthrough;
+	case -ECONNRESET:		/* unlink */
+	case -ESHUTDOWN:		/* disconnect etc */
+		break;
+	case 0:
+		break;
+	}
+
+	spin_lock(&dev->lock);
+	/* Take the request struct off the active list and put it on the
+	 * free list.
+	 */
+	list_del_init(&req->list);
+	list_add(&req->list, &dev->tx_reqs);
+	wake_up_interruptible(&dev->tx_wait);
+	if (likely(list_empty(&dev->tx_reqs_active)))
+		wake_up_interruptible(&dev->tx_flush_wait);
+
+	spin_unlock(&dev->lock);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int
+printer_open(struct inode *inode, struct file *fd)
+{
+	struct printer_dev	*dev;
+	unsigned long		flags;
+	int			ret = -EBUSY;
+
+	dev = container_of(inode->i_cdev, struct printer_dev, printer_cdev);
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->interface < 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		return -ENODEV;
+	}
+
+	if (!dev->printer_cdev_open) {
+		dev->printer_cdev_open = 1;
+		fd->private_data = dev;
+		ret = 0;
+		/* Change the printer status to show that it's on-line. */
+		dev->printer_status |= PRINTER_SELECTED;
+	}
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	kref_get(&dev->kref);
+	DBG(dev, "printer_open returned %x\n", ret);
+	return ret;
+}
+
+static int
+printer_close(struct inode *inode, struct file *fd)
+{
+	struct printer_dev	*dev = fd->private_data;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	dev->printer_cdev_open = 0;
+	fd->private_data = NULL;
+	/* Change printer status to show that the printer is off-line. */
+	dev->printer_status &= ~PRINTER_SELECTED;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	kref_put(&dev->kref, printer_dev_free);
+	DBG(dev, "printer_close\n");
+
+	return 0;
+}
+
+/* This function must be called with interrupts turned off. */
+static void
+setup_rx_reqs(struct printer_dev *dev)
+{
+	struct usb_request              *req;
+
+	while (likely(!list_empty(&dev->rx_reqs))) {
+		int error;
+
+		req = container_of(dev->rx_reqs.next,
+				struct usb_request, list);
+		list_del_init(&req->list);
+
+		/* The USB Host sends us whatever amount of data it wants to
+		 * so we always set the length field to the full USB_BUFSIZE.
+		 * If the amount of data is more than the read() caller asked
+		 * for it will be stored in the request buffer until it is
+		 * asked for by read().
+		 */
+		req->length = USB_BUFSIZE;
+		req->complete = rx_complete;
+
+		/* here, we unlock, and only unlock, to avoid deadlock. */
+		spin_unlock(&dev->lock);
+		error = usb_ep_queue(dev->out_ep, req, GFP_ATOMIC);
+		spin_lock(&dev->lock);
+		if (error) {
+			DBG(dev, "rx submit --> %d\n", error);
+			list_add(&req->list, &dev->rx_reqs);
+			break;
+		}
+		/* if the req is empty, then add it into dev->rx_reqs_active. */
+		else if (list_empty(&req->list))
+			list_add(&req->list, &dev->rx_reqs_active);
+	}
+}
+
+static ssize_t
+printer_read(struct file *fd, char __user *buf, size_t len, loff_t *ptr)
+{
+	struct printer_dev		*dev = fd->private_data;
+	unsigned long			flags;
+	size_t				size;
+	size_t				bytes_copied;
+	struct usb_request		*req;
+	/* This is a pointer to the current USB rx request. */
+	struct usb_request		*current_rx_req;
+	/* This is the number of bytes in the current rx buffer. */
+	size_t				current_rx_bytes;
+	/* This is a pointer to the current rx buffer. */
+	u8				*current_rx_buf;
+
+	if (len == 0)
+		return -EINVAL;
+
+	DBG(dev, "printer_read trying to read %d bytes\n", (int)len);
+
+	mutex_lock(&dev->lock_printer_io);
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->interface < 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		mutex_unlock(&dev->lock_printer_io);
+		return -ENODEV;
+	}
+
+	/* We will use this flag later to check if a printer reset happened
+	 * after we turn interrupts back on.
+	 */
+	dev->reset_printer = 0;
+
+	setup_rx_reqs(dev);
+
+	bytes_copied = 0;
+	current_rx_req = dev->current_rx_req;
+	current_rx_bytes = dev->current_rx_bytes;
+	current_rx_buf = dev->current_rx_buf;
+	dev->current_rx_req = NULL;
+	dev->current_rx_bytes = 0;
+	dev->current_rx_buf = NULL;
+
+	/* Check if there is any data in the read buffers. Please note that
+	 * current_rx_bytes is the number of bytes in the current rx buffer.
+	 * If it is zero then check if there are any other rx_buffers that
+	 * are on the completed list. We are only out of data if all rx
+	 * buffers are empty.
+	 */
+	if ((current_rx_bytes == 0) &&
+			(likely(list_empty(&dev->rx_buffers)))) {
+		/* Turn interrupts back on before sleeping. */
+		spin_unlock_irqrestore(&dev->lock, flags);
+
+		/*
+		 * If no data is available check if this is a NON-Blocking
+		 * call or not.
+		 */
+		if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
+			mutex_unlock(&dev->lock_printer_io);
+			return -EAGAIN;
+		}
+
+		/* Sleep until data is available */
+		wait_event_interruptible(dev->rx_wait,
+				(likely(!list_empty(&dev->rx_buffers))));
+		spin_lock_irqsave(&dev->lock, flags);
+	}
+
+	/* We have data to return then copy it to the caller's buffer.*/
+	while ((current_rx_bytes || likely(!list_empty(&dev->rx_buffers)))
+			&& len) {
+		if (current_rx_bytes == 0) {
+			req = container_of(dev->rx_buffers.next,
+					struct usb_request, list);
+			list_del_init(&req->list);
+
+			if (req->actual && req->buf) {
+				current_rx_req = req;
+				current_rx_bytes = req->actual;
+				current_rx_buf = req->buf;
+			} else {
+				list_add(&req->list, &dev->rx_reqs);
+				continue;
+			}
+		}
+
+		/* Don't leave irqs off while doing memory copies */
+		spin_unlock_irqrestore(&dev->lock, flags);
+
+		if (len > current_rx_bytes)
+			size = current_rx_bytes;
+		else
+			size = len;
+
+		size -= copy_to_user(buf, current_rx_buf, size);
+		bytes_copied += size;
+		len -= size;
+		buf += size;
+
+		spin_lock_irqsave(&dev->lock, flags);
+
+		/* We've disconnected or reset so return. */
+		if (dev->reset_printer) {
+			list_add(&current_rx_req->list, &dev->rx_reqs);
+			spin_unlock_irqrestore(&dev->lock, flags);
+			mutex_unlock(&dev->lock_printer_io);
+			return -EAGAIN;
+		}
+
+		/* If we not returning all the data left in this RX request
+		 * buffer then adjust the amount of data left in the buffer.
+		 * Othewise if we are done with this RX request buffer then
+		 * requeue it to get any incoming data from the USB host.
+		 */
+		if (size < current_rx_bytes) {
+			current_rx_bytes -= size;
+			current_rx_buf += size;
+		} else {
+			list_add(&current_rx_req->list, &dev->rx_reqs);
+			current_rx_bytes = 0;
+			current_rx_buf = NULL;
+			current_rx_req = NULL;
+		}
+	}
+
+	dev->current_rx_req = current_rx_req;
+	dev->current_rx_bytes = current_rx_bytes;
+	dev->current_rx_buf = current_rx_buf;
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock_printer_io);
+
+	DBG(dev, "printer_read returned %d bytes\n", (int)bytes_copied);
+
+	if (bytes_copied)
+		return bytes_copied;
+	else
+		return -EAGAIN;
+}
+
+static ssize_t
+printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
+{
+	struct printer_dev	*dev = fd->private_data;
+	unsigned long		flags;
+	size_t			size;	/* Amount of data in a TX request. */
+	size_t			bytes_copied = 0;
+	struct usb_request	*req;
+	int			value;
+
+	DBG(dev, "printer_write trying to send %d bytes\n", (int)len);
+
+	if (len == 0)
+		return -EINVAL;
+
+	mutex_lock(&dev->lock_printer_io);
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->interface < 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		mutex_unlock(&dev->lock_printer_io);
+		return -ENODEV;
+	}
+
+	/* Check if a printer reset happens while we have interrupts on */
+	dev->reset_printer = 0;
+
+	/* Check if there is any available write buffers */
+	if (likely(list_empty(&dev->tx_reqs))) {
+		/* Turn interrupts back on before sleeping. */
+		spin_unlock_irqrestore(&dev->lock, flags);
+
+		/*
+		 * If write buffers are available check if this is
+		 * a NON-Blocking call or not.
+		 */
+		if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
+			mutex_unlock(&dev->lock_printer_io);
+			return -EAGAIN;
+		}
+
+		/* Sleep until a write buffer is available */
+		wait_event_interruptible(dev->tx_wait,
+				(likely(!list_empty(&dev->tx_reqs))));
+		spin_lock_irqsave(&dev->lock, flags);
+	}
+
+	while (likely(!list_empty(&dev->tx_reqs)) && len) {
+
+		if (len > USB_BUFSIZE)
+			size = USB_BUFSIZE;
+		else
+			size = len;
+
+		req = container_of(dev->tx_reqs.next, struct usb_request,
+				list);
+		list_del_init(&req->list);
+
+		req->complete = tx_complete;
+		req->length = size;
+
+		/* Check if we need to send a zero length packet. */
+		if (len > size)
+			/* They will be more TX requests so no yet. */
+			req->zero = 0;
+		else
+			/* If the data amount is not a multiple of the
+			 * maxpacket size then send a zero length packet.
+			 */
+			req->zero = ((len % dev->in_ep->maxpacket) == 0);
+
+		/* Don't leave irqs off while doing memory copies */
+		spin_unlock_irqrestore(&dev->lock, flags);
+
+		if (copy_from_user(req->buf, buf, size)) {
+			list_add(&req->list, &dev->tx_reqs);
+			mutex_unlock(&dev->lock_printer_io);
+			return bytes_copied;
+		}
+
+		bytes_copied += size;
+		len -= size;
+		buf += size;
+
+		spin_lock_irqsave(&dev->lock, flags);
+
+		/* We've disconnected or reset so free the req and buffer */
+		if (dev->reset_printer) {
+			list_add(&req->list, &dev->tx_reqs);
+			spin_unlock_irqrestore(&dev->lock, flags);
+			mutex_unlock(&dev->lock_printer_io);
+			return -EAGAIN;
+		}
+
+		list_add(&req->list, &dev->tx_reqs_active);
+
+		/* here, we unlock, and only unlock, to avoid deadlock. */
+		spin_unlock(&dev->lock);
+		value = usb_ep_queue(dev->in_ep, req, GFP_ATOMIC);
+		spin_lock(&dev->lock);
+		if (value) {
+			list_move(&req->list, &dev->tx_reqs);
+			spin_unlock_irqrestore(&dev->lock, flags);
+			mutex_unlock(&dev->lock_printer_io);
+			return -EAGAIN;
+		}
+	}
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock_printer_io);
+
+	DBG(dev, "printer_write sent %d bytes\n", (int)bytes_copied);
+
+	if (bytes_copied)
+		return bytes_copied;
+	else
+		return -EAGAIN;
+}
+
+static int
+printer_fsync(struct file *fd, loff_t start, loff_t end, int datasync)
+{
+	struct printer_dev	*dev = fd->private_data;
+	struct inode *inode = file_inode(fd);
+	unsigned long		flags;
+	int			tx_list_empty;
+
+	inode_lock(inode);
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->interface < 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		inode_unlock(inode);
+		return -ENODEV;
+	}
+
+	tx_list_empty = (likely(list_empty(&dev->tx_reqs)));
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	if (!tx_list_empty) {
+		/* Sleep until all data has been sent */
+		wait_event_interruptible(dev->tx_flush_wait,
+				(likely(list_empty(&dev->tx_reqs_active))));
+	}
+	inode_unlock(inode);
+
+	return 0;
+}
+
+static __poll_t
+printer_poll(struct file *fd, poll_table *wait)
+{
+	struct printer_dev	*dev = fd->private_data;
+	unsigned long		flags;
+	__poll_t		status = 0;
+
+	mutex_lock(&dev->lock_printer_io);
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->interface < 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		mutex_unlock(&dev->lock_printer_io);
+		return EPOLLERR | EPOLLHUP;
+	}
+
+	setup_rx_reqs(dev);
+	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock_printer_io);
+
+	poll_wait(fd, &dev->rx_wait, wait);
+	poll_wait(fd, &dev->tx_wait, wait);
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (likely(!list_empty(&dev->tx_reqs)))
+		status |= EPOLLOUT | EPOLLWRNORM;
+
+	if (likely(dev->current_rx_bytes) ||
+			likely(!list_empty(&dev->rx_buffers)))
+		status |= EPOLLIN | EPOLLRDNORM;
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	return status;
+}
+
+static long
+printer_ioctl(struct file *fd, unsigned int code, unsigned long arg)
+{
+	struct printer_dev	*dev = fd->private_data;
+	unsigned long		flags;
+	int			status = 0;
+
+	DBG(dev, "printer_ioctl: cmd=0x%4.4x, arg=%lu\n", code, arg);
+
+	/* handle ioctls */
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->interface < 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		return -ENODEV;
+	}
+
+	switch (code) {
+	case GADGET_GET_PRINTER_STATUS:
+		status = (int)dev->printer_status;
+		break;
+	case GADGET_SET_PRINTER_STATUS:
+		dev->printer_status = (u8)arg;
+		break;
+	default:
+		/* could not handle ioctl */
+		DBG(dev, "printer_ioctl: ERROR cmd=0x%4.4xis not supported\n",
+				code);
+		status = -ENOTTY;
+	}
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	return status;
+}
+
+/* used after endpoint configuration */
+static const struct file_operations printer_io_operations = {
+	.owner =	THIS_MODULE,
+	.open =		printer_open,
+	.read =		printer_read,
+	.write =	printer_write,
+	.fsync =	printer_fsync,
+	.poll =		printer_poll,
+	.unlocked_ioctl = printer_ioctl,
+	.release =	printer_close,
+	.llseek =	noop_llseek,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int
+set_printer_interface(struct printer_dev *dev)
+{
+	int			result = 0;
+
+	dev->in_ep->desc = ep_desc(dev->gadget, &fs_ep_in_desc, &hs_ep_in_desc,
+				&ss_ep_in_desc);
+	dev->in_ep->driver_data = dev;
+
+	dev->out_ep->desc = ep_desc(dev->gadget, &fs_ep_out_desc,
+				    &hs_ep_out_desc, &ss_ep_out_desc);
+	dev->out_ep->driver_data = dev;
+
+	result = usb_ep_enable(dev->in_ep);
+	if (result != 0) {
+		DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
+		goto done;
+	}
+
+	result = usb_ep_enable(dev->out_ep);
+	if (result != 0) {
+		DBG(dev, "enable %s --> %d\n", dev->out_ep->name, result);
+		goto done;
+	}
+
+done:
+	/* on error, disable any endpoints  */
+	if (result != 0) {
+		(void) usb_ep_disable(dev->in_ep);
+		(void) usb_ep_disable(dev->out_ep);
+		dev->in_ep->desc = NULL;
+		dev->out_ep->desc = NULL;
+	}
+
+	/* caller is responsible for cleanup on error */
+	return result;
+}
+
+static void printer_reset_interface(struct printer_dev *dev)
+{
+	unsigned long	flags;
+
+	if (dev->interface < 0)
+		return;
+
+	DBG(dev, "%s\n", __func__);
+
+	if (dev->in_ep->desc)
+		usb_ep_disable(dev->in_ep);
+
+	if (dev->out_ep->desc)
+		usb_ep_disable(dev->out_ep);
+
+	spin_lock_irqsave(&dev->lock, flags);
+	dev->in_ep->desc = NULL;
+	dev->out_ep->desc = NULL;
+	dev->interface = -1;
+	spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+/* Change our operational Interface. */
+static int set_interface(struct printer_dev *dev, unsigned number)
+{
+	int			result = 0;
+
+	/* Free the current interface */
+	printer_reset_interface(dev);
+
+	result = set_printer_interface(dev);
+	if (result)
+		printer_reset_interface(dev);
+	else
+		dev->interface = number;
+
+	if (!result)
+		INFO(dev, "Using interface %x\n", number);
+
+	return result;
+}
+
+static void printer_soft_reset(struct printer_dev *dev)
+{
+	struct usb_request	*req;
+
+	INFO(dev, "Received Printer Reset Request\n");
+
+	if (usb_ep_disable(dev->in_ep))
+		DBG(dev, "Failed to disable USB in_ep\n");
+	if (usb_ep_disable(dev->out_ep))
+		DBG(dev, "Failed to disable USB out_ep\n");
+
+	if (dev->current_rx_req != NULL) {
+		list_add(&dev->current_rx_req->list, &dev->rx_reqs);
+		dev->current_rx_req = NULL;
+	}
+	dev->current_rx_bytes = 0;
+	dev->current_rx_buf = NULL;
+	dev->reset_printer = 1;
+
+	while (likely(!(list_empty(&dev->rx_buffers)))) {
+		req = container_of(dev->rx_buffers.next, struct usb_request,
+				list);
+		list_del_init(&req->list);
+		list_add(&req->list, &dev->rx_reqs);
+	}
+
+	while (likely(!(list_empty(&dev->rx_reqs_active)))) {
+		req = container_of(dev->rx_buffers.next, struct usb_request,
+				list);
+		list_del_init(&req->list);
+		list_add(&req->list, &dev->rx_reqs);
+	}
+
+	while (likely(!(list_empty(&dev->tx_reqs_active)))) {
+		req = container_of(dev->tx_reqs_active.next,
+				struct usb_request, list);
+		list_del_init(&req->list);
+		list_add(&req->list, &dev->tx_reqs);
+	}
+
+	if (usb_ep_enable(dev->in_ep))
+		DBG(dev, "Failed to enable USB in_ep\n");
+	if (usb_ep_enable(dev->out_ep))
+		DBG(dev, "Failed to enable USB out_ep\n");
+
+	wake_up_interruptible(&dev->rx_wait);
+	wake_up_interruptible(&dev->tx_wait);
+	wake_up_interruptible(&dev->tx_flush_wait);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static bool gprinter_req_match(struct usb_function *f,
+			       const struct usb_ctrlrequest *ctrl,
+			       bool config0)
+{
+	struct printer_dev	*dev = func_to_printer(f);
+	u16			w_index = le16_to_cpu(ctrl->wIndex);
+	u16			w_value = le16_to_cpu(ctrl->wValue);
+	u16			w_length = le16_to_cpu(ctrl->wLength);
+
+	if (config0)
+		return false;
+
+	if ((ctrl->bRequestType & USB_RECIP_MASK) != USB_RECIP_INTERFACE ||
+	    (ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
+		return false;
+
+	switch (ctrl->bRequest) {
+	case GET_DEVICE_ID:
+		w_index >>= 8;
+		if (USB_DIR_IN & ctrl->bRequestType)
+			break;
+		return false;
+	case GET_PORT_STATUS:
+		if (!w_value && w_length == 1 &&
+		    (USB_DIR_IN & ctrl->bRequestType))
+			break;
+		return false;
+	case SOFT_RESET:
+		if (!w_value && !w_length &&
+		   !(USB_DIR_IN & ctrl->bRequestType))
+			break;
+		fallthrough;
+	default:
+		return false;
+	}
+	return w_index == dev->interface;
+}
+
+/*
+ * The setup() callback implements all the ep0 functionality that's not
+ * handled lower down.
+ */
+static int printer_func_setup(struct usb_function *f,
+		const struct usb_ctrlrequest *ctrl)
+{
+	struct printer_dev *dev = func_to_printer(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct usb_request	*req = cdev->req;
+	u8			*buf = req->buf;
+	int			value = -EOPNOTSUPP;
+	u16			wIndex = le16_to_cpu(ctrl->wIndex);
+	u16			wValue = le16_to_cpu(ctrl->wValue);
+	u16			wLength = le16_to_cpu(ctrl->wLength);
+
+	DBG(dev, "ctrl req%02x.%02x v%04x i%04x l%d\n",
+		ctrl->bRequestType, ctrl->bRequest, wValue, wIndex, wLength);
+
+	switch (ctrl->bRequestType&USB_TYPE_MASK) {
+	case USB_TYPE_CLASS:
+		switch (ctrl->bRequest) {
+		case GET_DEVICE_ID: /* Get the IEEE-1284 PNP String */
+			/* Only one printer interface is supported. */
+			if ((wIndex>>8) != dev->interface)
+				break;
+
+			if (!*dev->pnp_string) {
+				value = 0;
+				break;
+			}
+			value = strlen(*dev->pnp_string);
+			buf[0] = (value >> 8) & 0xFF;
+			buf[1] = value & 0xFF;
+			memcpy(buf + 2, *dev->pnp_string, value);
+			DBG(dev, "1284 PNP String: %x %s\n", value,
+			    *dev->pnp_string);
+			break;
+
+		case GET_PORT_STATUS: /* Get Port Status */
+			/* Only one printer interface is supported. */
+			if (wIndex != dev->interface)
+				break;
+
+			buf[0] = dev->printer_status;
+			value = min_t(u16, wLength, 1);
+			break;
+
+		case SOFT_RESET: /* Soft Reset */
+			/* Only one printer interface is supported. */
+			if (wIndex != dev->interface)
+				break;
+
+			printer_soft_reset(dev);
+
+			value = 0;
+			break;
+
+		default:
+			goto unknown;
+		}
+		break;
+
+	default:
+unknown:
+		VDBG(dev,
+			"unknown ctrl req%02x.%02x v%04x i%04x l%d\n",
+			ctrl->bRequestType, ctrl->bRequest,
+			wValue, wIndex, wLength);
+		break;
+	}
+	/* host either stalls (value < 0) or reports success */
+	if (value >= 0) {
+		req->length = value;
+		req->zero = value < wLength;
+		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+		if (value < 0) {
+			ERROR(dev, "%s:%d Error!\n", __func__, __LINE__);
+			req->status = 0;
+		}
+	}
+	return value;
+}
+
+static int printer_func_bind(struct usb_configuration *c,
+		struct usb_function *f)
+{
+	struct usb_gadget *gadget = c->cdev->gadget;
+	struct printer_dev *dev = func_to_printer(f);
+	struct device *pdev;
+	struct usb_composite_dev *cdev = c->cdev;
+	struct usb_ep *in_ep;
+	struct usb_ep *out_ep = NULL;
+	struct usb_request *req;
+	dev_t devt;
+	int id;
+	int ret;
+	u32 i;
+
+	id = usb_interface_id(c, f);
+	if (id < 0)
+		return id;
+	intf_desc.bInterfaceNumber = id;
+
+	/* finish hookup to lower layer ... */
+	dev->gadget = gadget;
+
+	/* all we really need is bulk IN/OUT */
+	in_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_in_desc);
+	if (!in_ep) {
+autoconf_fail:
+		dev_err(&cdev->gadget->dev, "can't autoconfigure on %s\n",
+			cdev->gadget->name);
+		return -ENODEV;
+	}
+
+	out_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_out_desc);
+	if (!out_ep)
+		goto autoconf_fail;
+
+	/* assumes that all endpoints are dual-speed */
+	hs_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
+	hs_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
+	ss_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
+	ss_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
+
+	ret = usb_assign_descriptors(f, fs_printer_function,
+			hs_printer_function, ss_printer_function,
+			ss_printer_function);
+	if (ret)
+		return ret;
+
+	dev->in_ep = in_ep;
+	dev->out_ep = out_ep;
+
+	ret = -ENOMEM;
+	for (i = 0; i < dev->q_len; i++) {
+		req = printer_req_alloc(dev->in_ep, USB_BUFSIZE, GFP_KERNEL);
+		if (!req)
+			goto fail_tx_reqs;
+		list_add(&req->list, &dev->tx_reqs);
+	}
+
+	for (i = 0; i < dev->q_len; i++) {
+		req = printer_req_alloc(dev->out_ep, USB_BUFSIZE, GFP_KERNEL);
+		if (!req)
+			goto fail_rx_reqs;
+		list_add(&req->list, &dev->rx_reqs);
+	}
+
+	/* Setup the sysfs files for the printer gadget. */
+	devt = MKDEV(major, dev->minor);
+	pdev = device_create(usb_gadget_class, NULL, devt,
+				  NULL, "g_printer%d", dev->minor);
+	if (IS_ERR(pdev)) {
+		ERROR(dev, "Failed to create device: g_printer\n");
+		ret = PTR_ERR(pdev);
+		goto fail_rx_reqs;
+	}
+
+	/*
+	 * Register a character device as an interface to a user mode
+	 * program that handles the printer specific functionality.
+	 */
+	cdev_init(&dev->printer_cdev, &printer_io_operations);
+	dev->printer_cdev.owner = THIS_MODULE;
+	ret = cdev_add(&dev->printer_cdev, devt, 1);
+	if (ret) {
+		ERROR(dev, "Failed to open char device\n");
+		goto fail_cdev_add;
+	}
+
+	return 0;
+
+fail_cdev_add:
+	device_destroy(usb_gadget_class, devt);
+
+fail_rx_reqs:
+	while (!list_empty(&dev->rx_reqs)) {
+		req = container_of(dev->rx_reqs.next, struct usb_request, list);
+		list_del(&req->list);
+		printer_req_free(dev->out_ep, req);
+	}
+
+fail_tx_reqs:
+	while (!list_empty(&dev->tx_reqs)) {
+		req = container_of(dev->tx_reqs.next, struct usb_request, list);
+		list_del(&req->list);
+		printer_req_free(dev->in_ep, req);
+	}
+
+	usb_free_all_descriptors(f);
+	return ret;
+
+}
+
+static int printer_func_set_alt(struct usb_function *f,
+		unsigned intf, unsigned alt)
+{
+	struct printer_dev *dev = func_to_printer(f);
+	int ret = -ENOTSUPP;
+
+	if (!alt)
+		ret = set_interface(dev, intf);
+
+	return ret;
+}
+
+static void printer_func_disable(struct usb_function *f)
+{
+	struct printer_dev *dev = func_to_printer(f);
+
+	DBG(dev, "%s\n", __func__);
+
+	printer_reset_interface(dev);
+}
+
+static inline struct f_printer_opts
+*to_f_printer_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_printer_opts,
+			    func_inst.group);
+}
+
+static void printer_attr_release(struct config_item *item)
+{
+	struct f_printer_opts *opts = to_f_printer_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations printer_item_ops = {
+	.release	= printer_attr_release,
+};
+
+static ssize_t f_printer_opts_pnp_string_show(struct config_item *item,
+					      char *page)
+{
+	struct f_printer_opts *opts = to_f_printer_opts(item);
+	int result = 0;
+
+	mutex_lock(&opts->lock);
+	if (!opts->pnp_string)
+		goto unlock;
+
+	result = strlcpy(page, opts->pnp_string, PAGE_SIZE);
+	if (result >= PAGE_SIZE) {
+		result = PAGE_SIZE;
+	} else if (page[result - 1] != '\n' && result + 1 < PAGE_SIZE) {
+		page[result++] = '\n';
+		page[result] = '\0';
+	}
+
+unlock:
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_printer_opts_pnp_string_store(struct config_item *item,
+					       const char *page, size_t len)
+{
+	struct f_printer_opts *opts = to_f_printer_opts(item);
+	char *new_pnp;
+	int result;
+
+	mutex_lock(&opts->lock);
+
+	new_pnp = kstrndup(page, len, GFP_KERNEL);
+	if (!new_pnp) {
+		result = -ENOMEM;
+		goto unlock;
+	}
+
+	if (opts->pnp_string_allocated)
+		kfree(opts->pnp_string);
+
+	opts->pnp_string_allocated = true;
+	opts->pnp_string = new_pnp;
+	result = len;
+unlock:
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+CONFIGFS_ATTR(f_printer_opts_, pnp_string);
+
+static ssize_t f_printer_opts_q_len_show(struct config_item *item,
+					 char *page)
+{
+	struct f_printer_opts *opts = to_f_printer_opts(item);
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d\n", opts->q_len);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_printer_opts_q_len_store(struct config_item *item,
+					  const char *page, size_t len)
+{
+	struct f_printer_opts *opts = to_f_printer_opts(item);
+	int ret;
+	u16 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou16(page, 0, &num);
+	if (ret)
+		goto end;
+
+	opts->q_len = (unsigned)num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+CONFIGFS_ATTR(f_printer_opts_, q_len);
+
+static struct configfs_attribute *printer_attrs[] = {
+	&f_printer_opts_attr_pnp_string,
+	&f_printer_opts_attr_q_len,
+	NULL,
+};
+
+static const struct config_item_type printer_func_type = {
+	.ct_item_ops	= &printer_item_ops,
+	.ct_attrs	= printer_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static inline int gprinter_get_minor(void)
+{
+	int ret;
+
+	ret = ida_simple_get(&printer_ida, 0, 0, GFP_KERNEL);
+	if (ret >= PRINTER_MINORS) {
+		ida_simple_remove(&printer_ida, ret);
+		ret = -ENODEV;
+	}
+
+	return ret;
+}
+
+static inline void gprinter_put_minor(int minor)
+{
+	ida_simple_remove(&printer_ida, minor);
+}
+
+static int gprinter_setup(int);
+static void gprinter_cleanup(void);
+
+static void gprinter_free_inst(struct usb_function_instance *f)
+{
+	struct f_printer_opts *opts;
+
+	opts = container_of(f, struct f_printer_opts, func_inst);
+
+	mutex_lock(&printer_ida_lock);
+
+	gprinter_put_minor(opts->minor);
+	if (ida_is_empty(&printer_ida))
+		gprinter_cleanup();
+
+	mutex_unlock(&printer_ida_lock);
+
+	if (opts->pnp_string_allocated)
+		kfree(opts->pnp_string);
+	kfree(opts);
+}
+
+static struct usb_function_instance *gprinter_alloc_inst(void)
+{
+	struct f_printer_opts *opts;
+	struct usb_function_instance *ret;
+	int status = 0;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&opts->lock);
+	opts->func_inst.free_func_inst = gprinter_free_inst;
+	ret = &opts->func_inst;
+
+	/* Make sure q_len is initialized, otherwise the bound device can't support read/write! */
+	opts->q_len = DEFAULT_Q_LEN;
+
+	mutex_lock(&printer_ida_lock);
+
+	if (ida_is_empty(&printer_ida)) {
+		status = gprinter_setup(PRINTER_MINORS);
+		if (status) {
+			ret = ERR_PTR(status);
+			kfree(opts);
+			goto unlock;
+		}
+	}
+
+	opts->minor = gprinter_get_minor();
+	if (opts->minor < 0) {
+		ret = ERR_PTR(opts->minor);
+		kfree(opts);
+		if (ida_is_empty(&printer_ida))
+			gprinter_cleanup();
+		goto unlock;
+	}
+	config_group_init_type_name(&opts->func_inst.group, "",
+				    &printer_func_type);
+
+unlock:
+	mutex_unlock(&printer_ida_lock);
+	return ret;
+}
+
+static void gprinter_free(struct usb_function *f)
+{
+	struct printer_dev *dev = func_to_printer(f);
+	struct f_printer_opts *opts;
+
+	opts = container_of(f->fi, struct f_printer_opts, func_inst);
+
+	kref_put(&dev->kref, printer_dev_free);
+	mutex_lock(&opts->lock);
+	--opts->refcnt;
+	mutex_unlock(&opts->lock);
+}
+
+static void printer_func_unbind(struct usb_configuration *c,
+		struct usb_function *f)
+{
+	struct printer_dev	*dev;
+	struct usb_request	*req;
+
+	dev = func_to_printer(f);
+
+	device_destroy(usb_gadget_class, MKDEV(major, dev->minor));
+
+	/* Remove Character Device */
+	cdev_del(&dev->printer_cdev);
+
+	/* we must already have been disconnected ... no i/o may be active */
+	WARN_ON(!list_empty(&dev->tx_reqs_active));
+	WARN_ON(!list_empty(&dev->rx_reqs_active));
+
+	/* Free all memory for this driver. */
+	while (!list_empty(&dev->tx_reqs)) {
+		req = container_of(dev->tx_reqs.next, struct usb_request,
+				list);
+		list_del(&req->list);
+		printer_req_free(dev->in_ep, req);
+	}
+
+	if (dev->current_rx_req != NULL)
+		printer_req_free(dev->out_ep, dev->current_rx_req);
+
+	while (!list_empty(&dev->rx_reqs)) {
+		req = container_of(dev->rx_reqs.next,
+				struct usb_request, list);
+		list_del(&req->list);
+		printer_req_free(dev->out_ep, req);
+	}
+
+	while (!list_empty(&dev->rx_buffers)) {
+		req = container_of(dev->rx_buffers.next,
+				struct usb_request, list);
+		list_del(&req->list);
+		printer_req_free(dev->out_ep, req);
+	}
+	usb_free_all_descriptors(f);
+}
+
+static struct usb_function *gprinter_alloc(struct usb_function_instance *fi)
+{
+	struct printer_dev	*dev;
+	struct f_printer_opts	*opts;
+
+	opts = container_of(fi, struct f_printer_opts, func_inst);
+
+	mutex_lock(&opts->lock);
+	if (opts->minor >= minors) {
+		mutex_unlock(&opts->lock);
+		return ERR_PTR(-ENOENT);
+	}
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		mutex_unlock(&opts->lock);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	kref_init(&dev->kref);
+	++opts->refcnt;
+	dev->minor = opts->minor;
+	dev->pnp_string = &opts->pnp_string;
+	dev->q_len = opts->q_len;
+	mutex_unlock(&opts->lock);
+
+	dev->function.name = "printer";
+	dev->function.bind = printer_func_bind;
+	dev->function.setup = printer_func_setup;
+	dev->function.unbind = printer_func_unbind;
+	dev->function.set_alt = printer_func_set_alt;
+	dev->function.disable = printer_func_disable;
+	dev->function.req_match = gprinter_req_match;
+	dev->function.free_func = gprinter_free;
+
+	INIT_LIST_HEAD(&dev->tx_reqs);
+	INIT_LIST_HEAD(&dev->rx_reqs);
+	INIT_LIST_HEAD(&dev->rx_buffers);
+	INIT_LIST_HEAD(&dev->tx_reqs_active);
+	INIT_LIST_HEAD(&dev->rx_reqs_active);
+
+	spin_lock_init(&dev->lock);
+	mutex_init(&dev->lock_printer_io);
+	init_waitqueue_head(&dev->rx_wait);
+	init_waitqueue_head(&dev->tx_wait);
+	init_waitqueue_head(&dev->tx_flush_wait);
+
+	dev->interface = -1;
+	dev->printer_cdev_open = 0;
+	dev->printer_status = PRINTER_NOT_ERROR;
+	dev->current_rx_req = NULL;
+	dev->current_rx_bytes = 0;
+	dev->current_rx_buf = NULL;
+
+	return &dev->function;
+}
+
+DECLARE_USB_FUNCTION_INIT(printer, gprinter_alloc_inst, gprinter_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Craig Nadler");
+
+static int gprinter_setup(int count)
+{
+	int status;
+	dev_t devt;
+
+	usb_gadget_class = class_create(THIS_MODULE, "usb_printer_gadget");
+	if (IS_ERR(usb_gadget_class)) {
+		status = PTR_ERR(usb_gadget_class);
+		usb_gadget_class = NULL;
+		pr_err("unable to create usb_gadget class %d\n", status);
+		return status;
+	}
+
+	status = alloc_chrdev_region(&devt, 0, count, "USB printer gadget");
+	if (status) {
+		pr_err("alloc_chrdev_region %d\n", status);
+		class_destroy(usb_gadget_class);
+		usb_gadget_class = NULL;
+		return status;
+	}
+
+	major = MAJOR(devt);
+	minors = count;
+
+	return status;
+}
+
+static void gprinter_cleanup(void)
+{
+	if (major) {
+		unregister_chrdev_region(MKDEV(major, 0), minors);
+		major = minors = 0;
+	}
+	class_destroy(usb_gadget_class);
+	usb_gadget_class = NULL;
+}