drivers/usb/gadget/f_hid.c - kernel/msm-4.19 - Gitiles

 /*
  * f_hid.c -- USB HID function driver
  *
  * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

 #include <linux/kernel.h>
 #include <linux/utsname.h>
 #include <linux/module.h>
 #include <linux/hid.h>
 #include <linux/cdev.h>
 #include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/uaccess.h>
 #include <linux/wait.h>
 #include <linux/usb/g_hid.h>

 static int major, minors;
 static struct class *hidg_class;

 /*-------------------------------------------------------------------------*/
 /*                            HID gadget struct                            */

 struct f_hidg {
 	/* configuration */
 	unsigned char			bInterfaceSubClass;
 	unsigned char			bInterfaceProtocol;
 	unsigned short			report_desc_length;
 	char				*report_desc;
 	unsigned short			report_length;

 	/* recv report */
 	char				*set_report_buff;
 	unsigned short			set_report_length;
 	spinlock_t			spinlock;
 	wait_queue_head_t		read_queue;

 	/* send report */
 	struct mutex			lock;
 	bool				write_pending;
 	wait_queue_head_t		write_queue;
 	struct usb_request		*req;

 	int				minor;
 	struct cdev			cdev;
 	struct usb_function		func;
 	struct usb_ep			*in_ep;
 };

 static inline struct f_hidg *func_to_hidg(struct usb_function *f)
 {
 	return container_of(f, struct f_hidg, func);
 }

 /*-------------------------------------------------------------------------*/
 /*                           Static descriptors                            */

 static struct usb_interface_descriptor hidg_interface_desc = {
 	.bLength		= sizeof hidg_interface_desc,
 	.bDescriptorType	= USB_DT_INTERFACE,
 	/* .bInterfaceNumber	= DYNAMIC */
 	.bAlternateSetting	= 0,
 	.bNumEndpoints		= 1,
 	.bInterfaceClass	= USB_CLASS_HID,
 	/* .bInterfaceSubClass	= DYNAMIC */
 	/* .bInterfaceProtocol	= DYNAMIC */
 	/* .iInterface		= DYNAMIC */
 };

 static struct hid_descriptor hidg_desc = {
 	.bLength			= sizeof hidg_desc,
 	.bDescriptorType		= HID_DT_HID,
 	.bcdHID				= 0x0101,
 	.bCountryCode			= 0x00,
 	.bNumDescriptors		= 0x1,
 	/*.desc[0].bDescriptorType	= DYNAMIC */
 	/*.desc[0].wDescriptorLenght	= DYNAMIC */
 };

 /* High-Speed Support */

 static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
 	.bLength		= USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType	= USB_DT_ENDPOINT,
 	.bEndpointAddress	= USB_DIR_IN,
 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
 	/*.wMaxPacketSize	= DYNAMIC */
 	.bInterval		= 4, /* FIXME: Add this field in the
 				      * HID gadget configuration?
 				      * (struct hidg_func_descriptor)
 				      */
 };

 static struct usb_descriptor_header *hidg_hs_descriptors[] = {
 	(struct usb_descriptor_header *)&hidg_interface_desc,
 	(struct usb_descriptor_header *)&hidg_desc,
 	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
 	NULL,
 };

 /* Full-Speed Support */

 static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
 	.bLength		= USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType	= USB_DT_ENDPOINT,
 	.bEndpointAddress	= USB_DIR_IN,
 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
 	/*.wMaxPacketSize	= DYNAMIC */
 	.bInterval		= 10, /* FIXME: Add this field in the
 				       * HID gadget configuration?
 				       * (struct hidg_func_descriptor)
 				       */
 };

 static struct usb_descriptor_header *hidg_fs_descriptors[] = {
 	(struct usb_descriptor_header *)&hidg_interface_desc,
 	(struct usb_descriptor_header *)&hidg_desc,
 	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
 	NULL,
 };

 /*-------------------------------------------------------------------------*/
 /*                              Char Device                                */

 static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 			size_t count, loff_t *ptr)
 {
 	struct f_hidg	*hidg     = file->private_data;
 	char		*tmp_buff = NULL;
 	unsigned long	flags;

 	if (!count)
 		return 0;

 	if (!access_ok(VERIFY_WRITE, buffer, count))
 		return -EFAULT;

 	spin_lock_irqsave(&hidg->spinlock, flags);

 #define READ_COND (hidg->set_report_buff != NULL)

 	while (!READ_COND) {
 		spin_unlock_irqrestore(&hidg->spinlock, flags);
 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;

 		if (wait_event_interruptible(hidg->read_queue, READ_COND))
 			return -ERESTARTSYS;

 		spin_lock_irqsave(&hidg->spinlock, flags);
 	}


 	count = min_t(unsigned, count, hidg->set_report_length);
 	tmp_buff = hidg->set_report_buff;
 	hidg->set_report_buff = NULL;

 	spin_unlock_irqrestore(&hidg->spinlock, flags);

 	if (tmp_buff != NULL) {
 		/* copy to user outside spinlock */
 		count -= copy_to_user(buffer, tmp_buff, count);
 		kfree(tmp_buff);
 	} else
 		count = -ENOMEM;

 	return count;
 }

 static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;

 	if (req->status != 0) {
 		ERROR(hidg->func.config->cdev,
 			"End Point Request ERROR: %d\n", req->status);
 	}

 	hidg->write_pending = 0;
 	wake_up(&hidg->write_queue);
 }

 static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
 			    size_t count, loff_t *offp)
 {
 	struct f_hidg *hidg  = file->private_data;
 	ssize_t status = -ENOMEM;

 	if (!access_ok(VERIFY_READ, buffer, count))
 		return -EFAULT;

 	mutex_lock(&hidg->lock);

 #define WRITE_COND (!hidg->write_pending)

 	/* write queue */
 	while (!WRITE_COND) {
 		mutex_unlock(&hidg->lock);
 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;

 		if (wait_event_interruptible_exclusive(
 				hidg->write_queue, WRITE_COND))
 			return -ERESTARTSYS;

 		mutex_lock(&hidg->lock);
 	}

 	count  = min_t(unsigned, count, hidg->report_length);
 	status = copy_from_user(hidg->req->buf, buffer, count);

 	if (status != 0) {
 		ERROR(hidg->func.config->cdev,
 			"copy_from_user error\n");
 		mutex_unlock(&hidg->lock);
 		return -EINVAL;
 	}

 	hidg->req->status   = 0;
 	hidg->req->zero     = 0;
 	hidg->req->length   = count;
 	hidg->req->complete = f_hidg_req_complete;
 	hidg->req->context  = hidg;
 	hidg->write_pending = 1;

 	status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);
 	if (status < 0) {
 		ERROR(hidg->func.config->cdev,
 			"usb_ep_queue error on int endpoint %zd\n", status);
 		hidg->write_pending = 0;
 		wake_up(&hidg->write_queue);
 	} else {
 		status = count;
 	}

 	mutex_unlock(&hidg->lock);

 	return status;
 }

 static unsigned int f_hidg_poll(struct file *file, poll_table *wait)
 {
 	struct f_hidg	*hidg  = file->private_data;
 	unsigned int	ret = 0;

 	poll_wait(file, &hidg->read_queue, wait);
 	poll_wait(file, &hidg->write_queue, wait);

 	if (WRITE_COND)
 		ret |= POLLOUT | POLLWRNORM;

 	if (READ_COND)
 		ret |= POLLIN | POLLRDNORM;

 	return ret;
 }

 #undef WRITE_COND
 #undef READ_COND

 static int f_hidg_release(struct inode *inode, struct file *fd)
 {
 	fd->private_data = NULL;
 	return 0;
 }

 static int f_hidg_open(struct inode *inode, struct file *fd)
 {
 	struct f_hidg *hidg =
 		container_of(inode->i_cdev, struct f_hidg, cdev);

 	fd->private_data = hidg;

 	return 0;
 }

 /*-------------------------------------------------------------------------*/
 /*                                usb_function                             */

 static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_hidg *hidg = (struct f_hidg *)req->context;

 	if (req->status != 0 || req->buf == NULL || req->actual == 0) {
 		ERROR(hidg->func.config->cdev, "%s FAILED\n", __func__);
 		return;
 	}

 	spin_lock(&hidg->spinlock);

 	hidg->set_report_buff = krealloc(hidg->set_report_buff,
 					 req->actual, GFP_ATOMIC);

 	if (hidg->set_report_buff == NULL) {
 		spin_unlock(&hidg->spinlock);
 		return;
 	}
 	hidg->set_report_length = req->actual;
 	memcpy(hidg->set_report_buff, req->buf, req->actual);

 	spin_unlock(&hidg->spinlock);

 	wake_up(&hidg->read_queue);
 }

 static int hidg_setup(struct usb_function *f,
 		const struct usb_ctrlrequest *ctrl)
 {
 	struct f_hidg			*hidg = func_to_hidg(f);
 	struct usb_composite_dev	*cdev = f->config->cdev;
 	struct usb_request		*req  = cdev->req;
 	int status = 0;
 	__u16 value, length;

 	value	= __le16_to_cpu(ctrl->wValue);
 	length	= __le16_to_cpu(ctrl->wLength);

 	VDBG(cdev, "hid_setup crtl_request : bRequestType:0x%x bRequest:0x%x "
 		"Value:0x%x\n", ctrl->bRequestType, ctrl->bRequest, value);

 	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_GET_REPORT):
 		VDBG(cdev, "get_report\n");

 		/* send an empty report */
 		length = min_t(unsigned, length, hidg->report_length);
 		memset(req->buf, 0x0, length);

 		goto respond;
 		break;

 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_GET_PROTOCOL):
 		VDBG(cdev, "get_protocol\n");
 		goto stall;
 		break;

 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_SET_REPORT):
 		VDBG(cdev, "set_report | wLenght=%d\n", ctrl->wLength);
 		req->context  = hidg;
 		req->complete = hidg_set_report_complete;
 		goto respond;
 		break;

 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_SET_PROTOCOL):
 		VDBG(cdev, "set_protocol\n");
 		goto stall;
 		break;

 	case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
 		  | USB_REQ_GET_DESCRIPTOR):
 		switch (value >> 8) {
 		case HID_DT_REPORT:
 			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
 			length = min_t(unsigned short, length,
 						   hidg->report_desc_length);
 			memcpy(req->buf, hidg->report_desc, length);
 			goto respond;
 			break;

 		default:
 			VDBG(cdev, "Unknown decriptor request 0x%x\n",
 				 value >> 8);
 			goto stall;
 			break;
 		}
 		break;

 	default:
 		VDBG(cdev, "Unknown request 0x%x\n",
 			 ctrl->bRequest);
 		goto stall;
 		break;
 	}

 stall:
 	return -EOPNOTSUPP;

 respond:
 	req->zero = 0;
 	req->length = length;
 	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 	if (status < 0)
 		ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
 	return status;
 }

 static void hidg_disable(struct usb_function *f)
 {
 	struct f_hidg *hidg = func_to_hidg(f);

 	usb_ep_disable(hidg->in_ep);
 	hidg->in_ep->driver_data = NULL;
 }

 static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 {
 	struct usb_composite_dev		*cdev = f->config->cdev;
 	struct f_hidg				*hidg = func_to_hidg(f);
 	int status = 0;

 	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);

 	if (hidg->in_ep != NULL) {
 		/* restart endpoint */
 		if (hidg->in_ep->driver_data != NULL)
 			usb_ep_disable(hidg->in_ep);

 		status = config_ep_by_speed(f->config->cdev->gadget, f,
 					    hidg->in_ep);
 		if (status) {
 			ERROR(cdev, "config_ep_by_speed FAILED!\n");
 			goto fail;
 		}
 		status = usb_ep_enable(hidg->in_ep);
 		if (status < 0) {
 			ERROR(cdev, "Enable endpoint FAILED!\n");
 			goto fail;
 		}
 		hidg->in_ep->driver_data = hidg;
 	}
 fail:
 	return status;
 }

 const struct file_operations f_hidg_fops = {
 	.owner		= THIS_MODULE,
 	.open		= f_hidg_open,
 	.release	= f_hidg_release,
 	.write		= f_hidg_write,
 	.read		= f_hidg_read,
 	.poll		= f_hidg_poll,
 	.llseek		= noop_llseek,
 };

 static int __init hidg_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_ep		*ep;
 	struct f_hidg		*hidg = func_to_hidg(f);
 	int			status;
 	dev_t			dev;

 	/* allocate instance-specific interface IDs, and patch descriptors */
 	status = usb_interface_id(c, f);
 	if (status < 0)
 		goto fail;
 	hidg_interface_desc.bInterfaceNumber = status;


 	/* allocate instance-specific endpoints */
 	status = -ENODEV;
 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
 	if (!ep)
 		goto fail;
 	ep->driver_data = c->cdev;	/* claim */
 	hidg->in_ep = ep;

 	/* preallocate request and buffer */
 	status = -ENOMEM;
 	hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);
 	if (!hidg->req)
 		goto fail;


 	hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);
 	if (!hidg->req->buf)
 		goto fail;

 	/* set descriptor dynamic values */
 	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
 	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
 	hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 	hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
 	hidg_desc.desc[0].wDescriptorLength =
 		cpu_to_le16(hidg->report_desc_length);

 	hidg->set_report_buff = NULL;

 	/* copy descriptors */
 	f->descriptors = usb_copy_descriptors(hidg_fs_descriptors);
 	if (!f->descriptors)
 		goto fail;

 	if (gadget_is_dualspeed(c->cdev->gadget)) {
 		hidg_hs_in_ep_desc.bEndpointAddress =
 			hidg_fs_in_ep_desc.bEndpointAddress;
 		f->hs_descriptors = usb_copy_descriptors(hidg_hs_descriptors);
 		if (!f->hs_descriptors)
 			goto fail;
 	}

 	mutex_init(&hidg->lock);
 	spin_lock_init(&hidg->spinlock);
 	init_waitqueue_head(&hidg->write_queue);
 	init_waitqueue_head(&hidg->read_queue);

 	/* create char device */
 	cdev_init(&hidg->cdev, &f_hidg_fops);
 	dev = MKDEV(major, hidg->minor);
 	status = cdev_add(&hidg->cdev, dev, 1);
 	if (status)
 		goto fail;

 	device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);

 	return 0;

 fail:
 	ERROR(f->config->cdev, "hidg_bind FAILED\n");
 	if (hidg->req != NULL) {
 		kfree(hidg->req->buf);
 		if (hidg->in_ep != NULL)
 			usb_ep_free_request(hidg->in_ep, hidg->req);
 	}

 	usb_free_descriptors(f->hs_descriptors);
 	usb_free_descriptors(f->descriptors);

 	return status;
 }

 static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_hidg *hidg = func_to_hidg(f);

 	device_destroy(hidg_class, MKDEV(major, hidg->minor));
 	cdev_del(&hidg->cdev);

 	/* disable/free request and end point */
 	usb_ep_disable(hidg->in_ep);
 	usb_ep_dequeue(hidg->in_ep, hidg->req);
 	kfree(hidg->req->buf);
 	usb_ep_free_request(hidg->in_ep, hidg->req);

 	/* free descriptors copies */
 	usb_free_descriptors(f->hs_descriptors);
 	usb_free_descriptors(f->descriptors);

 	kfree(hidg->report_desc);
 	kfree(hidg->set_report_buff);
 	kfree(hidg);
 }

 /*-------------------------------------------------------------------------*/
 /*                                 Strings                                 */

 #define CT_FUNC_HID_IDX	0

 static struct usb_string ct_func_string_defs[] = {
 	[CT_FUNC_HID_IDX].s	= "HID Interface",
 	{},			/* end of list */
 };

 static struct usb_gadget_strings ct_func_string_table = {
 	.language	= 0x0409,	/* en-US */
 	.strings	= ct_func_string_defs,
 };

 static struct usb_gadget_strings *ct_func_strings[] = {
 	&ct_func_string_table,
 	NULL,
 };

 /*-------------------------------------------------------------------------*/
 /*                             usb_configuration                           */

 int __init hidg_bind_config(struct usb_configuration *c,
 			    struct hidg_func_descriptor *fdesc, int index)
 {
 	struct f_hidg *hidg;
 	int status;

 	if (index >= minors)
 		return -ENOENT;

 	/* maybe allocate device-global string IDs, and patch descriptors */
 	if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
 		status = usb_string_id(c->cdev);
 		if (status < 0)
 			return status;
 		ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
 		hidg_interface_desc.iInterface = status;
 	}

 	/* allocate and initialize one new instance */
 	hidg = kzalloc(sizeof *hidg, GFP_KERNEL);
 	if (!hidg)
 		return -ENOMEM;

 	hidg->minor = index;
 	hidg->bInterfaceSubClass = fdesc->subclass;
 	hidg->bInterfaceProtocol = fdesc->protocol;
 	hidg->report_length = fdesc->report_length;
 	hidg->report_desc_length = fdesc->report_desc_length;
 	hidg->report_desc = kmemdup(fdesc->report_desc,
 				    fdesc->report_desc_length,
 				    GFP_KERNEL);
 	if (!hidg->report_desc) {
 		kfree(hidg);
 		return -ENOMEM;
 	}

 	hidg->func.name    = "hid";
 	hidg->func.strings = ct_func_strings;
 	hidg->func.bind    = hidg_bind;
 	hidg->func.unbind  = hidg_unbind;
 	hidg->func.set_alt = hidg_set_alt;
 	hidg->func.disable = hidg_disable;
 	hidg->func.setup   = hidg_setup;

 	status = usb_add_function(c, &hidg->func);
 	if (status)
 		kfree(hidg);

 	return status;
 }

 int __init ghid_setup(struct usb_gadget *g, int count)
 {
 	int status;
 	dev_t dev;

 	hidg_class = class_create(THIS_MODULE, "hidg");

 	status = alloc_chrdev_region(&dev, 0, count, "hidg");
 	if (!status) {
 		major = MAJOR(dev);
 		minors = count;
 	}

 	return status;
 }

 void ghid_cleanup(void)
 {
 	if (major) {
 		unregister_chrdev_region(MKDEV(major, 0), minors);
 		major = minors = 0;
 	}

 	class_destroy(hidg_class);
 	hidg_class = NULL;
 }
	/*
	* f_hid.c -- USB HID function driver
	*
	* Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/kernel.h>
	#include <linux/utsname.h>
	#include <linux/module.h>
	#include <linux/hid.h>
	#include <linux/cdev.h>
	#include <linux/mutex.h>
	#include <linux/poll.h>
	#include <linux/uaccess.h>
	#include <linux/wait.h>
	#include <linux/usb/g_hid.h>

	static int major, minors;
	static struct class *hidg_class;

	/-------------------------------------------------------------------------/
	/* HID gadget struct */

	struct f_hidg {
	/* configuration */
	unsigned char bInterfaceSubClass;
	unsigned char bInterfaceProtocol;
	unsigned short report_desc_length;
	char *report_desc;
	unsigned short report_length;

	/* recv report */
	char *set_report_buff;
	unsigned short set_report_length;
	spinlock_t spinlock;
	wait_queue_head_t read_queue;

	/* send report */
	struct mutex lock;
	bool write_pending;
	wait_queue_head_t write_queue;
	struct usb_request *req;

	int minor;
	struct cdev cdev;
	struct usb_function func;
	struct usb_ep *in_ep;
	};

	static inline struct f_hidg func_to_hidg(struct usb_function f)
	{
	return container_of(f, struct f_hidg, func);
	}

	/-------------------------------------------------------------------------/
	/* Static descriptors */

	static struct usb_interface_descriptor hidg_interface_desc = {
	.bLength = sizeof hidg_interface_desc,
	.bDescriptorType = USB_DT_INTERFACE,
	/* .bInterfaceNumber = DYNAMIC */
	.bAlternateSetting = 0,
	.bNumEndpoints = 1,
	.bInterfaceClass = USB_CLASS_HID,
	/* .bInterfaceSubClass = DYNAMIC */
	/* .bInterfaceProtocol = DYNAMIC */
	/* .iInterface = DYNAMIC */
	};

	static struct hid_descriptor hidg_desc = {
	.bLength = sizeof hidg_desc,
	.bDescriptorType = HID_DT_HID,
	.bcdHID = 0x0101,
	.bCountryCode = 0x00,
	.bNumDescriptors = 0x1,
	/.desc[0].bDescriptorType = DYNAMIC /
	/.desc[0].wDescriptorLenght = DYNAMIC /
	};

	/* High-Speed Support */

	static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = USB_DIR_IN,
	.bmAttributes = USB_ENDPOINT_XFER_INT,
	/.wMaxPacketSize = DYNAMIC /
	.bInterval = 4, /* FIXME: Add this field in the
	* HID gadget configuration?
	* (struct hidg_func_descriptor)
	*/
	};

	static struct usb_descriptor_header *hidg_hs_descriptors[] = {
	(struct usb_descriptor_header *)&hidg_interface_desc,
	(struct usb_descriptor_header *)&hidg_desc,
	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
	NULL,
	};

	/* Full-Speed Support */

	static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = USB_DIR_IN,
	.bmAttributes = USB_ENDPOINT_XFER_INT,
	/.wMaxPacketSize = DYNAMIC /
	.bInterval = 10, /* FIXME: Add this field in the
	* HID gadget configuration?
	* (struct hidg_func_descriptor)
	*/
	};

	static struct usb_descriptor_header *hidg_fs_descriptors[] = {
	(struct usb_descriptor_header *)&hidg_interface_desc,
	(struct usb_descriptor_header *)&hidg_desc,
	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
	NULL,
	};

	/-------------------------------------------------------------------------/
	/* Char Device */

	static ssize_t f_hidg_read(struct file file, char __user buffer,
	size_t count, loff_t *ptr)
	{
	struct f_hidg *hidg = file->private_data;
	char *tmp_buff = NULL;
	unsigned long flags;

	if (!count)
	return 0;

	if (!access_ok(VERIFY_WRITE, buffer, count))
	return -EFAULT;

	spin_lock_irqsave(&hidg->spinlock, flags);

	#define READ_COND (hidg->set_report_buff != NULL)

	while (!READ_COND) {
	spin_unlock_irqrestore(&hidg->spinlock, flags);
	if (file->f_flags & O_NONBLOCK)
	return -EAGAIN;

	if (wait_event_interruptible(hidg->read_queue, READ_COND))
	return -ERESTARTSYS;

	spin_lock_irqsave(&hidg->spinlock, flags);
	}


	count = min_t(unsigned, count, hidg->set_report_length);
	tmp_buff = hidg->set_report_buff;
	hidg->set_report_buff = NULL;

	spin_unlock_irqrestore(&hidg->spinlock, flags);

	if (tmp_buff != NULL) {
	/* copy to user outside spinlock */
	count -= copy_to_user(buffer, tmp_buff, count);
	kfree(tmp_buff);
	} else
	count = -ENOMEM;

	return count;
	}

	static void f_hidg_req_complete(struct usb_ep ep, struct usb_request req)
	{
	struct f_hidg hidg = (struct f_hidg )ep->driver_data;

	if (req->status != 0) {
	ERROR(hidg->func.config->cdev,
	"End Point Request ERROR: %d\n", req->status);
	}

	hidg->write_pending = 0;
	wake_up(&hidg->write_queue);
	}

	static ssize_t f_hidg_write(struct file file, const char __user buffer,
	size_t count, loff_t *offp)
	{
	struct f_hidg *hidg = file->private_data;
	ssize_t status = -ENOMEM;

	if (!access_ok(VERIFY_READ, buffer, count))
	return -EFAULT;

	mutex_lock(&hidg->lock);

	#define WRITE_COND (!hidg->write_pending)

	/* write queue */
	while (!WRITE_COND) {
	mutex_unlock(&hidg->lock);
	if (file->f_flags & O_NONBLOCK)
	return -EAGAIN;

	if (wait_event_interruptible_exclusive(
	hidg->write_queue, WRITE_COND))
	return -ERESTARTSYS;

	mutex_lock(&hidg->lock);
	}

	count = min_t(unsigned, count, hidg->report_length);
	status = copy_from_user(hidg->req->buf, buffer, count);

	if (status != 0) {
	ERROR(hidg->func.config->cdev,
	"copy_from_user error\n");
	mutex_unlock(&hidg->lock);
	return -EINVAL;
	}

	hidg->req->status = 0;
	hidg->req->zero = 0;
	hidg->req->length = count;
	hidg->req->complete = f_hidg_req_complete;
	hidg->req->context = hidg;
	hidg->write_pending = 1;

	status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);
	if (status < 0) {
	ERROR(hidg->func.config->cdev,
	"usb_ep_queue error on int endpoint %zd\n", status);
	hidg->write_pending = 0;
	wake_up(&hidg->write_queue);
	} else {
	status = count;
	}

	mutex_unlock(&hidg->lock);

	return status;
	}

	static unsigned int f_hidg_poll(struct file file, poll_table wait)
	{
	struct f_hidg *hidg = file->private_data;
	unsigned int ret = 0;

	poll_wait(file, &hidg->read_queue, wait);
	poll_wait(file, &hidg->write_queue, wait);

	if (WRITE_COND)
	ret \|= POLLOUT \| POLLWRNORM;

	if (READ_COND)
	ret \|= POLLIN \| POLLRDNORM;

	return ret;
	}

	#undef WRITE_COND
	#undef READ_COND

	static int f_hidg_release(struct inode inode, struct file fd)
	{
	fd->private_data = NULL;
	return 0;
	}

	static int f_hidg_open(struct inode inode, struct file fd)
	{
	struct f_hidg *hidg =
	container_of(inode->i_cdev, struct f_hidg, cdev);

	fd->private_data = hidg;

	return 0;
	}

	/-------------------------------------------------------------------------/
	/* usb_function */

	static void hidg_set_report_complete(struct usb_ep ep, struct usb_request req)
	{
	struct f_hidg hidg = (struct f_hidg )req->context;

	if (req->status != 0 \|\| req->buf == NULL \|\| req->actual == 0) {
	ERROR(hidg->func.config->cdev, "%s FAILED\n", __func__);
	return;
	}

	spin_lock(&hidg->spinlock);

	hidg->set_report_buff = krealloc(hidg->set_report_buff,
	req->actual, GFP_ATOMIC);

	if (hidg->set_report_buff == NULL) {
	spin_unlock(&hidg->spinlock);
	return;
	}
	hidg->set_report_length = req->actual;
	memcpy(hidg->set_report_buff, req->buf, req->actual);

	spin_unlock(&hidg->spinlock);

	wake_up(&hidg->read_queue);
	}

	static int hidg_setup(struct usb_function *f,
	const struct usb_ctrlrequest *ctrl)
	{
	struct f_hidg *hidg = func_to_hidg(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct usb_request *req = cdev->req;
	int status = 0;
	__u16 value, length;

	value = __le16_to_cpu(ctrl->wValue);
	length = __le16_to_cpu(ctrl->wLength);

	VDBG(cdev, "hid_setup crtl_request : bRequestType:0x%x bRequest:0x%x "
	"Value:0x%x\n", ctrl->bRequestType, ctrl->bRequest, value);

	switch ((ctrl->bRequestType << 8) \| ctrl->bRequest) {
	case ((USB_DIR_IN \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE) << 8
	\| HID_REQ_GET_REPORT):
	VDBG(cdev, "get_report\n");

	/* send an empty report */
	length = min_t(unsigned, length, hidg->report_length);
	memset(req->buf, 0x0, length);

	goto respond;
	break;

	case ((USB_DIR_IN \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE) << 8
	\| HID_REQ_GET_PROTOCOL):
	VDBG(cdev, "get_protocol\n");
	goto stall;
	break;

	case ((USB_DIR_OUT \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE) << 8
	\| HID_REQ_SET_REPORT):
	VDBG(cdev, "set_report \| wLenght=%d\n", ctrl->wLength);
	req->context = hidg;
	req->complete = hidg_set_report_complete;
	goto respond;
	break;

	case ((USB_DIR_OUT \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE) << 8
	\| HID_REQ_SET_PROTOCOL):
	VDBG(cdev, "set_protocol\n");
	goto stall;
	break;

	case ((USB_DIR_IN \| USB_TYPE_STANDARD \| USB_RECIP_INTERFACE) << 8
	\| USB_REQ_GET_DESCRIPTOR):
	switch (value >> 8) {
	case HID_DT_REPORT:
	VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
	length = min_t(unsigned short, length,
	hidg->report_desc_length);
	memcpy(req->buf, hidg->report_desc, length);
	goto respond;
	break;

	default:
	VDBG(cdev, "Unknown decriptor request 0x%x\n",
	value >> 8);
	goto stall;
	break;
	}
	break;

	default:
	VDBG(cdev, "Unknown request 0x%x\n",
	ctrl->bRequest);
	goto stall;
	break;
	}

	stall:
	return -EOPNOTSUPP;

	respond:
	req->zero = 0;
	req->length = length;
	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
	if (status < 0)
	ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
	return status;
	}

	static void hidg_disable(struct usb_function *f)
	{
	struct f_hidg *hidg = func_to_hidg(f);

	usb_ep_disable(hidg->in_ep);
	hidg->in_ep->driver_data = NULL;
	}

	static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
	{
	struct usb_composite_dev *cdev = f->config->cdev;
	struct f_hidg *hidg = func_to_hidg(f);
	int status = 0;

	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);

	if (hidg->in_ep != NULL) {
	/* restart endpoint */
	if (hidg->in_ep->driver_data != NULL)
	usb_ep_disable(hidg->in_ep);

	status = config_ep_by_speed(f->config->cdev->gadget, f,
	hidg->in_ep);
	if (status) {
	ERROR(cdev, "config_ep_by_speed FAILED!\n");
	goto fail;
	}
	status = usb_ep_enable(hidg->in_ep);
	if (status < 0) {
	ERROR(cdev, "Enable endpoint FAILED!\n");
	goto fail;
	}
	hidg->in_ep->driver_data = hidg;
	}
	fail:
	return status;
	}

	const struct file_operations f_hidg_fops = {
	.owner = THIS_MODULE,
	.open = f_hidg_open,
	.release = f_hidg_release,
	.write = f_hidg_write,
	.read = f_hidg_read,
	.poll = f_hidg_poll,
	.llseek = noop_llseek,
	};

	static int __init hidg_bind(struct usb_configuration c, struct usb_function f)
	{
	struct usb_ep *ep;
	struct f_hidg *hidg = func_to_hidg(f);
	int status;
	dev_t dev;

	/* allocate instance-specific interface IDs, and patch descriptors */
	status = usb_interface_id(c, f);
	if (status < 0)
	goto fail;
	hidg_interface_desc.bInterfaceNumber = status;


	/* allocate instance-specific endpoints */
	status = -ENODEV;
	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
	if (!ep)
	goto fail;
	ep->driver_data = c->cdev; /* claim */
	hidg->in_ep = ep;

	/* preallocate request and buffer */
	status = -ENOMEM;
	hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);
	if (!hidg->req)
	goto fail;


	hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);
	if (!hidg->req->buf)
	goto fail;

	/* set descriptor dynamic values */
	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
	hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
	hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
	hidg_desc.desc[0].wDescriptorLength =
	cpu_to_le16(hidg->report_desc_length);

	hidg->set_report_buff = NULL;

	/* copy descriptors */
	f->descriptors = usb_copy_descriptors(hidg_fs_descriptors);
	if (!f->descriptors)
	goto fail;

	if (gadget_is_dualspeed(c->cdev->gadget)) {
	hidg_hs_in_ep_desc.bEndpointAddress =
	hidg_fs_in_ep_desc.bEndpointAddress;
	f->hs_descriptors = usb_copy_descriptors(hidg_hs_descriptors);
	if (!f->hs_descriptors)
	goto fail;
	}

	mutex_init(&hidg->lock);
	spin_lock_init(&hidg->spinlock);
	init_waitqueue_head(&hidg->write_queue);
	init_waitqueue_head(&hidg->read_queue);

	/* create char device */
	cdev_init(&hidg->cdev, &f_hidg_fops);
	dev = MKDEV(major, hidg->minor);
	status = cdev_add(&hidg->cdev, dev, 1);
	if (status)
	goto fail;

	device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);

	return 0;

	fail:
	ERROR(f->config->cdev, "hidg_bind FAILED\n");
	if (hidg->req != NULL) {
	kfree(hidg->req->buf);
	if (hidg->in_ep != NULL)
	usb_ep_free_request(hidg->in_ep, hidg->req);
	}

	usb_free_descriptors(f->hs_descriptors);
	usb_free_descriptors(f->descriptors);

	return status;
	}

	static void hidg_unbind(struct usb_configuration c, struct usb_function f)
	{
	struct f_hidg *hidg = func_to_hidg(f);

	device_destroy(hidg_class, MKDEV(major, hidg->minor));
	cdev_del(&hidg->cdev);

	/* disable/free request and end point */
	usb_ep_disable(hidg->in_ep);
	usb_ep_dequeue(hidg->in_ep, hidg->req);
	kfree(hidg->req->buf);
	usb_ep_free_request(hidg->in_ep, hidg->req);

	/* free descriptors copies */
	usb_free_descriptors(f->hs_descriptors);
	usb_free_descriptors(f->descriptors);

	kfree(hidg->report_desc);
	kfree(hidg->set_report_buff);
	kfree(hidg);
	}

	/-------------------------------------------------------------------------/
	/* Strings */

	#define CT_FUNC_HID_IDX 0

	static struct usb_string ct_func_string_defs[] = {
	[CT_FUNC_HID_IDX].s = "HID Interface",
	{}, /* end of list */
	};

	static struct usb_gadget_strings ct_func_string_table = {
	.language = 0x0409, /* en-US */
	.strings = ct_func_string_defs,
	};

	static struct usb_gadget_strings *ct_func_strings[] = {
	&ct_func_string_table,
	NULL,
	};

	/-------------------------------------------------------------------------/
	/* usb_configuration */

	int __init hidg_bind_config(struct usb_configuration *c,
	struct hidg_func_descriptor *fdesc, int index)
	{
	struct f_hidg *hidg;
	int status;

	if (index >= minors)
	return -ENOENT;

	/* maybe allocate device-global string IDs, and patch descriptors */
	if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
	status = usb_string_id(c->cdev);
	if (status < 0)
	return status;
	ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
	hidg_interface_desc.iInterface = status;
	}

	/* allocate and initialize one new instance */
	hidg = kzalloc(sizeof *hidg, GFP_KERNEL);
	if (!hidg)
	return -ENOMEM;

	hidg->minor = index;
	hidg->bInterfaceSubClass = fdesc->subclass;
	hidg->bInterfaceProtocol = fdesc->protocol;
	hidg->report_length = fdesc->report_length;
	hidg->report_desc_length = fdesc->report_desc_length;
	hidg->report_desc = kmemdup(fdesc->report_desc,
	fdesc->report_desc_length,
	GFP_KERNEL);
	if (!hidg->report_desc) {
	kfree(hidg);
	return -ENOMEM;
	}

	hidg->func.name = "hid";
	hidg->func.strings = ct_func_strings;
	hidg->func.bind = hidg_bind;
	hidg->func.unbind = hidg_unbind;
	hidg->func.set_alt = hidg_set_alt;
	hidg->func.disable = hidg_disable;
	hidg->func.setup = hidg_setup;

	status = usb_add_function(c, &hidg->func);
	if (status)
	kfree(hidg);

	return status;
	}

	int __init ghid_setup(struct usb_gadget *g, int count)
	{
	int status;
	dev_t dev;

	hidg_class = class_create(THIS_MODULE, "hidg");

	status = alloc_chrdev_region(&dev, 0, count, "hidg");
	if (!status) {
	major = MAJOR(dev);
	minors = count;
	}

	return status;
	}

	void ghid_cleanup(void)
	{
	if (major) {
	unregister_chrdev_region(MKDEV(major, 0), minors);
	major = minors = 0;
	}

	class_destroy(hidg_class);
	hidg_class = NULL;
	}