[mirror_ubuntu-jammy-kernel.git] / drivers / usb / misc / usblcd.c

// SPDX-License-Identifier: GPL-2.0
/*****************************************************************************
 *                          USBLCD Kernel Driver                             *
 *                            Version 1.05                                   *
 *             (C) 2005 Georges Toth <g.toth@e-biz.lu>                       *
 *                                                                           *
 *     This file is licensed under the GPL. See COPYING in the package.      *
 * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com)        *
 *                                                                           *
 *                                                                           *
 * 28.02.05 Complete rewrite of the original usblcd.c driver,                *
 *          based on usb_skeleton.c.                                         *
 *          This new driver allows more than one USB-LCD to be connected     *
 *          and controlled, at once                                          *
 *****************************************************************************/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/uaccess.h>
#include <linux/usb.h>

#define DRIVER_VERSION "USBLCD Driver Version 1.05"

#define USBLCD_MINOR		144

#define IOCTL_GET_HARD_VERSION	1
#define IOCTL_GET_DRV_VERSION	2


static const struct usb_device_id id_table[] = {
	{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
	{ },
};
MODULE_DEVICE_TABLE(usb, id_table);

struct usb_lcd {
	struct usb_device	*udev;			/* init: probe_lcd */
	struct usb_interface	*interface;		/* the interface for
							   this device */
	unsigned char		*bulk_in_buffer;	/* the buffer to receive
							   data */
	size_t			bulk_in_size;		/* the size of the
							   receive buffer */
	__u8			bulk_in_endpointAddr;	/* the address of the
							   bulk in endpoint */
	__u8			bulk_out_endpointAddr;	/* the address of the
							   bulk out endpoint */
	struct kref		kref;
	struct semaphore	limit_sem;		/* to stop writes at
							   full throttle from
							   using up all RAM */
	struct usb_anchor	submitted;		/* URBs to wait for
							   before suspend */
	struct rw_semaphore	io_rwsem;
	unsigned long		disconnected:1;
};
#define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)

#define USB_LCD_CONCURRENT_WRITES	5

static struct usb_driver lcd_driver;


static void lcd_delete(struct kref *kref)
{
	struct usb_lcd *dev = to_lcd_dev(kref);

	usb_put_dev(dev->udev);
	kfree(dev->bulk_in_buffer);
	kfree(dev);
}


static int lcd_open(struct inode *inode, struct file *file)
{
	struct usb_lcd *dev;
	struct usb_interface *interface;
	int subminor, r;

	subminor = iminor(inode);

	interface = usb_find_interface(&lcd_driver, subminor);
	if (!interface) {
		pr_err("USBLCD: %s - error, can't find device for minor %d\n",
		       __func__, subminor);
		return -ENODEV;
	}

	dev = usb_get_intfdata(interface);

	/* increment our usage count for the device */
	kref_get(&dev->kref);

	/* grab a power reference */
	r = usb_autopm_get_interface(interface);
	if (r < 0) {
		kref_put(&dev->kref, lcd_delete);
		return r;
	}

	/* save our object in the file's private structure */
	file->private_data = dev;

	return 0;
}

static int lcd_release(struct inode *inode, struct file *file)
{
	struct usb_lcd *dev;

	dev = file->private_data;
	if (dev == NULL)
		return -ENODEV;

	/* decrement the count on our device */
	usb_autopm_put_interface(dev->interface);
	kref_put(&dev->kref, lcd_delete);
	return 0;
}

static ssize_t lcd_read(struct file *file, char __user * buffer,
			size_t count, loff_t *ppos)
{
	struct usb_lcd *dev;
	int retval = 0;
	int bytes_read;

	dev = file->private_data;

	down_read(&dev->io_rwsem);

	if (dev->disconnected) {
		retval = -ENODEV;
		goto out_up_io;
	}

	/* do a blocking bulk read to get data from the device */
	retval = usb_bulk_msg(dev->udev,
			      usb_rcvbulkpipe(dev->udev,
					      dev->bulk_in_endpointAddr),
			      dev->bulk_in_buffer,
			      min(dev->bulk_in_size, count),
			      &bytes_read, 10000);

	/* if the read was successful, copy the data to userspace */
	if (!retval) {
		if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
			retval = -EFAULT;
		else
			retval = bytes_read;
	}

out_up_io:
	up_read(&dev->io_rwsem);

	return retval;
}

static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct usb_lcd *dev;
	u16 bcdDevice;
	char buf[30];

	dev = file->private_data;
	if (dev == NULL)
		return -ENODEV;

	switch (cmd) {
	case IOCTL_GET_HARD_VERSION:
		bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
		sprintf(buf, "%1d%1d.%1d%1d",
			(bcdDevice & 0xF000)>>12,
			(bcdDevice & 0xF00)>>8,
			(bcdDevice & 0xF0)>>4,
			(bcdDevice & 0xF));
		if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
			return -EFAULT;
		break;
	case IOCTL_GET_DRV_VERSION:
		sprintf(buf, DRIVER_VERSION);
		if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
			return -EFAULT;
		break;
	default:
		return -ENOTTY;
	}

	return 0;
}

static void lcd_write_bulk_callback(struct urb *urb)
{
	struct usb_lcd *dev;
	int status = urb->status;

	dev = urb->context;

	/* sync/async unlink faults aren't errors */
	if (status &&
	    !(status == -ENOENT ||
	      status == -ECONNRESET ||
	      status == -ESHUTDOWN)) {
		dev_dbg(&dev->interface->dev,
			"nonzero write bulk status received: %d\n", status);
	}

	/* free up our allocated buffer */
	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
			  urb->transfer_buffer, urb->transfer_dma);
	up(&dev->limit_sem);
}

static ssize_t lcd_write(struct file *file, const char __user * user_buffer,
			 size_t count, loff_t *ppos)
{
	struct usb_lcd *dev;
	int retval = 0, r;
	struct urb *urb = NULL;
	char *buf = NULL;

	dev = file->private_data;

	/* verify that we actually have some data to write */
	if (count == 0)
		goto exit;

	r = down_interruptible(&dev->limit_sem);
	if (r < 0)
		return -EINTR;

	down_read(&dev->io_rwsem);

	if (dev->disconnected) {
		retval = -ENODEV;
		goto err_up_io;
	}

	/* create a urb, and a buffer for it, and copy the data to the urb */
	urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!urb) {
		retval = -ENOMEM;
		goto err_up_io;
	}

	buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL,
				 &urb->transfer_dma);
	if (!buf) {
		retval = -ENOMEM;
		goto error;
	}

	if (copy_from_user(buf, user_buffer, count)) {
		retval = -EFAULT;
		goto error;
	}

	/* initialize the urb properly */
	usb_fill_bulk_urb(urb, dev->udev,
			  usb_sndbulkpipe(dev->udev,
			  dev->bulk_out_endpointAddr),
			  buf, count, lcd_write_bulk_callback, dev);
	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	usb_anchor_urb(urb, &dev->submitted);

	/* send the data out the bulk port */
	retval = usb_submit_urb(urb, GFP_KERNEL);
	if (retval) {
		dev_err(&dev->udev->dev,
			"%s - failed submitting write urb, error %d\n",
			__func__, retval);
		goto error_unanchor;
	}

	/* release our reference to this urb,
	   the USB core will eventually free it entirely */
	usb_free_urb(urb);

	up_read(&dev->io_rwsem);
exit:
	return count;
error_unanchor:
	usb_unanchor_urb(urb);
error:
	usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
	usb_free_urb(urb);
err_up_io:
	up_read(&dev->io_rwsem);
	up(&dev->limit_sem);
	return retval;
}

static const struct file_operations lcd_fops = {
	.owner =        THIS_MODULE,
	.read =         lcd_read,
	.write =        lcd_write,
	.open =         lcd_open,
	.unlocked_ioctl = lcd_ioctl,
	.release =      lcd_release,
	.llseek =	 noop_llseek,
};

/*
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with the driver core
 */
static struct usb_class_driver lcd_class = {
	.name =         "lcd%d",
	.fops =         &lcd_fops,
	.minor_base =   USBLCD_MINOR,
};

static int lcd_probe(struct usb_interface *interface,
		     const struct usb_device_id *id)
{
	struct usb_lcd *dev = NULL;
	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
	int i;
	int retval;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	kref_init(&dev->kref);
	sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
	init_rwsem(&dev->io_rwsem);
	init_usb_anchor(&dev->submitted);

	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;

	if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
		dev_warn(&interface->dev, "USBLCD model not supported.\n");
		retval = -ENODEV;
		goto error;
	}

	/* set up the endpoint information */
	/* use only the first bulk-in and bulk-out endpoints */
	retval = usb_find_common_endpoints(interface->cur_altsetting,
			&bulk_in, &bulk_out, NULL, NULL);
	if (retval) {
		dev_err(&interface->dev,
			"Could not find both bulk-in and bulk-out endpoints\n");
		goto error;
	}

	dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
	dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
	dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
	if (!dev->bulk_in_buffer) {
		retval = -ENOMEM;
		goto error;
	}

	dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;

	/* save our data pointer in this interface device */
	usb_set_intfdata(interface, dev);

	/* we can register the device now, as it is ready */
	retval = usb_register_dev(interface, &lcd_class);
	if (retval) {
		/* something prevented us from registering this driver */
		dev_err(&interface->dev,
			"Not able to get a minor for this device.\n");
		goto error;
	}

	i = le16_to_cpu(dev->udev->descriptor.bcdDevice);

	dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
		 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
		 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);

	/* let the user know what node this device is now attached to */
	dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
		 interface->minor);
	return 0;

error:
	kref_put(&dev->kref, lcd_delete);
	return retval;
}

static void lcd_draw_down(struct usb_lcd *dev)
{
	int time;

	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
	if (!time)
		usb_kill_anchored_urbs(&dev->submitted);
}

static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct usb_lcd *dev = usb_get_intfdata(intf);

	if (!dev)
		return 0;
	lcd_draw_down(dev);
	return 0;
}

static int lcd_resume(struct usb_interface *intf)
{
	return 0;
}

static void lcd_disconnect(struct usb_interface *interface)
{
	struct usb_lcd *dev = usb_get_intfdata(interface);
	int minor = interface->minor;

	/* give back our minor */
	usb_deregister_dev(interface, &lcd_class);

	down_write(&dev->io_rwsem);
	dev->disconnected = 1;
	up_write(&dev->io_rwsem);

	usb_kill_anchored_urbs(&dev->submitted);

	/* decrement our usage count */
	kref_put(&dev->kref, lcd_delete);

	dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
}

static struct usb_driver lcd_driver = {
	.name =		"usblcd",
	.probe =	lcd_probe,
	.disconnect =	lcd_disconnect,
	.suspend =	lcd_suspend,
	.resume =	lcd_resume,
	.id_table =	id_table,
	.supports_autosuspend = 1,
};

module_usb_driver(lcd_driver);

MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
MODULE_DESCRIPTION(DRIVER_VERSION);
MODULE_LICENSE("GPL");
Commit	Line	Data
5fd54ace	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*****************************************************************************
	3	* USBLCD Kernel Driver *
	4	* Version 1.05 *
	5	* (C) 2005 Georges Toth <g.toth@e-biz.lu> *
	6	* *
	7	* This file is licensed under the GPL. See COPYING in the package. *
	8	* Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com) *
	9	* *
	10	* *
	11	* 28.02.05 Complete rewrite of the original usblcd.c driver, *
	12	* based on usb_skeleton.c. *
	13	* This new driver allows more than one USB-LCD to be connected *
	14	* and controlled, at once *
	15	*****************************************************************************/
	16	#include <linux/module.h>
	17	#include <linux/kernel.h>
1da177e4 LT	18	#include <linux/slab.h>
1da177e4 LT	19	#include <linux/errno.h>
d5d1ceac	20	#include <linux/mutex.h>
eb7f5a49	21	#include <linux/rwsem.h>
507a3ea7	22	#include <linux/uaccess.h>
1da177e4 LT	23	#include <linux/usb.h>
	24
	25	#define DRIVER_VERSION "USBLCD Driver Version 1.05"
	26
	27	#define USBLCD_MINOR 144
	28
	29	#define IOCTL_GET_HARD_VERSION 1
	30	#define IOCTL_GET_DRV_VERSION 2
	31
	32
33b9e162	33	static const struct usb_device_id id_table[] = {
1da177e4 LT	34	{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
	35	{ },
	36	};
507a3ea7	37	MODULE_DEVICE_TABLE(usb, id_table);
1da177e4	38
1da177e4	39	struct usb_lcd {
507a3ea7 ZP	40	struct usb_device udev; / init: probe_lcd */
	41	struct usb_interface interface; / the interface for
	42	this device */
	43	unsigned char bulk_in_buffer; / the buffer to receive
	44	data */
	45	size_t bulk_in_size; /* the size of the
	46	receive buffer */
	47	__u8 bulk_in_endpointAddr; /* the address of the
	48	bulk in endpoint */
	49	__u8 bulk_out_endpointAddr; /* the address of the
	50	bulk out endpoint */
5afeb104	51	struct kref kref;
507a3ea7 ZP	52	struct semaphore limit_sem; /* to stop writes at
	53	full throttle from
	54	using up all RAM */
	55	struct usb_anchor submitted; /* URBs to wait for
	56	before suspend */
eb7f5a49 JH	57	struct rw_semaphore io_rwsem;
eb7f5a49 JH	58	unsigned long disconnected:1;
1da177e4 LT	59	};
	60	#define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
	61
5afeb104 ON	62	#define USB_LCD_CONCURRENT_WRITES 5
5afeb104 ON	63
1da177e4 LT	64	static struct usb_driver lcd_driver;
	65
	66
	67	static void lcd_delete(struct kref *kref)
	68	{
	69	struct usb_lcd *dev = to_lcd_dev(kref);
	70
	71	usb_put_dev(dev->udev);
507a3ea7 ZP	72	kfree(dev->bulk_in_buffer);
507a3ea7 ZP	73	kfree(dev);
1da177e4 LT	74	}
	75
	76
	77	static int lcd_open(struct inode inode, struct file file)
	78	{
	79	struct usb_lcd *dev;
	80	struct usb_interface *interface;
7bbe990c	81	int subminor, r;
1da177e4 LT	82
	83	subminor = iminor(inode);
	84
	85	interface = usb_find_interface(&lcd_driver, subminor);
	86	if (!interface) {
c9a2baa7	87	pr_err("USBLCD: %s - error, can't find device for minor %d\n",
abd83e4b	88	__func__, subminor);
d4ead16f	89	return -ENODEV;
1da177e4 LT	90	}
	91
	92	dev = usb_get_intfdata(interface);
1da177e4 LT	93
	94	/* increment our usage count for the device */
	95	kref_get(&dev->kref);
	96
7bbe990c ON	97	/* grab a power reference */
	98	r = usb_autopm_get_interface(interface);
	99	if (r < 0) {
	100	kref_put(&dev->kref, lcd_delete);
	101	return r;
	102	}
	103
1da177e4 LT	104	/* save our object in the file's private structure */
	105	file->private_data = dev;
	106
d4ead16f	107	return 0;
1da177e4 LT	108	}
	109
	110	static int lcd_release(struct inode inode, struct file file)
	111	{
	112	struct usb_lcd *dev;
	113
5bd6e8b3	114	dev = file->private_data;
1da177e4 LT	115	if (dev == NULL)
	116	return -ENODEV;
	117
	118	/* decrement the count on our device */
7bbe990c	119	usb_autopm_put_interface(dev->interface);
1da177e4 LT	120	kref_put(&dev->kref, lcd_delete);
	121	return 0;
	122	}
	123
507a3ea7 ZP	124	static ssize_t lcd_read(struct file file, char __user buffer,
507a3ea7 ZP	125	size_t count, loff_t *ppos)
1da177e4 LT	126	{
	127	struct usb_lcd *dev;
	128	int retval = 0;
	129	int bytes_read;
	130
5bd6e8b3	131	dev = file->private_data;
1da177e4	132
eb7f5a49 JH	133	down_read(&dev->io_rwsem);
	134
	135	if (dev->disconnected) {
	136	retval = -ENODEV;
	137	goto out_up_io;
	138	}
	139
1da177e4	140	/* do a blocking bulk read to get data from the device */
507a3ea7 ZP	141	retval = usb_bulk_msg(dev->udev,
	142	usb_rcvbulkpipe(dev->udev,
	143	dev->bulk_in_endpointAddr),
1da177e4 LT	144	dev->bulk_in_buffer,
	145	min(dev->bulk_in_size, count),
	146	&bytes_read, 10000);
	147
	148	/* if the read was successful, copy the data to userspace */
	149	if (!retval) {
	150	if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
	151	retval = -EFAULT;
	152	else
	153	retval = bytes_read;
	154	}
	155
eb7f5a49 JH	156	out_up_io:
	157	up_read(&dev->io_rwsem);
	158
1da177e4 LT	159	return retval;
	160	}
	161
5cb4aeca	162	static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	163	{
	164	struct usb_lcd *dev;
	165	u16 bcdDevice;
	166	char buf[30];
	167
5bd6e8b3	168	dev = file->private_data;
1da177e4 LT	169	if (dev == NULL)
1da177e4 LT	170	return -ENODEV;
507a3ea7	171
1da177e4 LT	172	switch (cmd) {
	173	case IOCTL_GET_HARD_VERSION:
	174	bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
507a3ea7	175	sprintf(buf, "%1d%1d.%1d%1d",
1da177e4 LT	176	(bcdDevice & 0xF000)>>12,
	177	(bcdDevice & 0xF00)>>8,
	178	(bcdDevice & 0xF0)>>4,
	179	(bcdDevice & 0xF));
507a3ea7	180	if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
1da177e4 LT	181	return -EFAULT;
	182	break;
	183	case IOCTL_GET_DRV_VERSION:
507a3ea7 ZP	184	sprintf(buf, DRIVER_VERSION);
507a3ea7 ZP	185	if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
1da177e4 LT	186	return -EFAULT;
	187	break;
	188	default:
	189	return -ENOTTY;
1da177e4 LT	190	}
	191
	192	return 0;
	193	}
	194
7d12e780	195	static void lcd_write_bulk_callback(struct urb *urb)
1da177e4 LT	196	{
1da177e4 LT	197	struct usb_lcd *dev;
0723af13	198	int status = urb->status;
1da177e4	199
cdc97792	200	dev = urb->context;
1da177e4 LT	201
1da177e4 LT	202	/* sync/async unlink faults aren't errors */
0723af13 GKH	203	if (status &&
	204	!(status == -ENOENT \|\|
	205	status == -ECONNRESET \|\|
507a3ea7	206	status == -ESHUTDOWN)) {
d8ec7a7c GKH	207	dev_dbg(&dev->interface->dev,
d8ec7a7c GKH	208	"nonzero write bulk status received: %d\n", status);
1da177e4 LT	209	}
	210
	211	/* free up our allocated buffer */
997ea58e DM	212	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
997ea58e DM	213	urb->transfer_buffer, urb->transfer_dma);
5afeb104	214	up(&dev->limit_sem);
1da177e4 LT	215	}
1da177e4 LT	216
507a3ea7 ZP	217	static ssize_t lcd_write(struct file file, const char __user user_buffer,
507a3ea7 ZP	218	size_t count, loff_t *ppos)
1da177e4 LT	219	{
1da177e4 LT	220	struct usb_lcd *dev;
507a3ea7	221	int retval = 0, r;
1da177e4 LT	222	struct urb *urb = NULL;
1da177e4 LT	223	char *buf = NULL;
507a3ea7	224
5bd6e8b3	225	dev = file->private_data;
507a3ea7	226
1da177e4 LT	227	/* verify that we actually have some data to write */
	228	if (count == 0)
	229	goto exit;
	230
5afeb104 ON	231	r = down_interruptible(&dev->limit_sem);
	232	if (r < 0)
	233	return -EINTR;
	234
eb7f5a49 JH	235	down_read(&dev->io_rwsem);
	236
	237	if (dev->disconnected) {
	238	retval = -ENODEV;
	239	goto err_up_io;
	240	}
	241
1da177e4 LT	242	/* create a urb, and a buffer for it, and copy the data to the urb */
1da177e4 LT	243	urb = usb_alloc_urb(0, GFP_KERNEL);
5afeb104 ON	244	if (!urb) {
5afeb104 ON	245	retval = -ENOMEM;
eb7f5a49	246	goto err_up_io;
5afeb104	247	}
507a3ea7 ZP	248
	249	buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL,
	250	&urb->transfer_dma);
1da177e4 LT	251	if (!buf) {
	252	retval = -ENOMEM;
	253	goto error;
	254	}
507a3ea7	255
1da177e4 LT	256	if (copy_from_user(buf, user_buffer, count)) {
	257	retval = -EFAULT;
	258	goto error;
	259	}
507a3ea7	260
1da177e4 LT	261	/* initialize the urb properly */
1da177e4 LT	262	usb_fill_bulk_urb(urb, dev->udev,
507a3ea7 ZP	263	usb_sndbulkpipe(dev->udev,
507a3ea7 ZP	264	dev->bulk_out_endpointAddr),
1da177e4 LT	265	buf, count, lcd_write_bulk_callback, dev);
1da177e4 LT	266	urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP;
7bbe990c ON	267
7bbe990c ON	268	usb_anchor_urb(urb, &dev->submitted);
507a3ea7	269
1da177e4 LT	270	/* send the data out the bulk port */
	271	retval = usb_submit_urb(urb, GFP_KERNEL);
	272	if (retval) {
abd83e4b GKH	273	dev_err(&dev->udev->dev,
	274	"%s - failed submitting write urb, error %d\n",
	275	__func__, retval);
7bbe990c	276	goto error_unanchor;
1da177e4	277	}
507a3ea7 ZP	278
	279	/* release our reference to this urb,
	280	the USB core will eventually free it entirely */
1da177e4 LT	281	usb_free_urb(urb);
1da177e4 LT	282
eb7f5a49	283	up_read(&dev->io_rwsem);
1da177e4 LT	284	exit:
1da177e4 LT	285	return count;
7bbe990c ON	286	error_unanchor:
7bbe990c ON	287	usb_unanchor_urb(urb);
1da177e4	288	error:
997ea58e	289	usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
1da177e4	290	usb_free_urb(urb);
eb7f5a49 JH	291	err_up_io:
eb7f5a49 JH	292	up_read(&dev->io_rwsem);
5afeb104	293	up(&dev->limit_sem);
1da177e4 LT	294	return retval;
	295	}
	296
066202dd	297	static const struct file_operations lcd_fops = {
507a3ea7 ZP	298	.owner = THIS_MODULE,
	299	.read = lcd_read,
	300	.write = lcd_write,
	301	.open = lcd_open,
5cb4aeca	302	.unlocked_ioctl = lcd_ioctl,
507a3ea7 ZP	303	.release = lcd_release,
507a3ea7 ZP	304	.llseek = noop_llseek,
1da177e4 LT	305	};
	306
	307	/*
d6e5bcf4 GKH	308	* usb class driver info in order to get a minor number from the usb core,
	309	* and to have the device registered with the driver core
	310	*/
1da177e4	311	static struct usb_class_driver lcd_class = {
507a3ea7 ZP	312	.name = "lcd%d",
	313	.fops = &lcd_fops,
	314	.minor_base = USBLCD_MINOR,
1da177e4 LT	315	};
1da177e4 LT	316
507a3ea7 ZP	317	static int lcd_probe(struct usb_interface *interface,
507a3ea7 ZP	318	const struct usb_device_id *id)
1da177e4 LT	319	{
1da177e4 LT	320	struct usb_lcd *dev = NULL;
aac96ef9	321	struct usb_endpoint_descriptor bulk_in, bulk_out;
1da177e4	322	int i;
aac96ef9	323	int retval;
1da177e4 LT	324
1da177e4 LT	325	/* allocate memory for our device state and initialize it */
80b6ca48	326	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
a1841732	327	if (!dev)
aac96ef9 JH	328	return -ENOMEM;
aac96ef9 JH	329
1da177e4	330	kref_init(&dev->kref);
5afeb104	331	sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
eb7f5a49	332	init_rwsem(&dev->io_rwsem);
7bbe990c	333	init_usb_anchor(&dev->submitted);
1da177e4 LT	334
	335	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	336	dev->interface = interface;
	337
	338	if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
3b6004f3	339	dev_warn(&interface->dev, "USBLCD model not supported.\n");
696a4ace JS	340	retval = -ENODEV;
696a4ace JS	341	goto error;
1da177e4	342	}
507a3ea7	343
1da177e4 LT	344	/* set up the endpoint information */
1da177e4 LT	345	/* use only the first bulk-in and bulk-out endpoints */
aac96ef9 JH	346	retval = usb_find_common_endpoints(interface->cur_altsetting,
	347	&bulk_in, &bulk_out, NULL, NULL);
	348	if (retval) {
abd83e4b GKH	349	dev_err(&interface->dev,
abd83e4b GKH	350	"Could not find both bulk-in and bulk-out endpoints\n");
1da177e4 LT	351	goto error;
	352	}
	353
aac96ef9 JH	354	dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
	355	dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
	356	dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
	357	if (!dev->bulk_in_buffer) {
	358	retval = -ENOMEM;
	359	goto error;
	360	}
	361
	362	dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
	363
1da177e4 LT	364	/* save our data pointer in this interface device */
	365	usb_set_intfdata(interface, dev);
	366
	367	/* we can register the device now, as it is ready */
	368	retval = usb_register_dev(interface, &lcd_class);
	369	if (retval) {
	370	/* something prevented us from registering this driver */
abd83e4b GKH	371	dev_err(&interface->dev,
abd83e4b GKH	372	"Not able to get a minor for this device.\n");
1da177e4 LT	373	goto error;
	374	}
	375
	376	i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
	377
1b29a375 GKH	378	dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
1b29a375 GKH	379	"at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
507a3ea7	380	(i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);
1da177e4 LT	381
1da177e4 LT	382	/* let the user know what node this device is now attached to */
1b29a375 GKH	383	dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
1b29a375 GKH	384	interface->minor);
1da177e4 LT	385	return 0;
	386
	387	error:
aac96ef9	388	kref_put(&dev->kref, lcd_delete);
1da177e4 LT	389	return retval;
	390	}
	391
7bbe990c ON	392	static void lcd_draw_down(struct usb_lcd *dev)
	393	{
	394	int time;
	395
	396	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
	397	if (!time)
	398	usb_kill_anchored_urbs(&dev->submitted);
	399	}
	400
	401	static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
	402	{
	403	struct usb_lcd *dev = usb_get_intfdata(intf);
	404
	405	if (!dev)
	406	return 0;
	407	lcd_draw_down(dev);
	408	return 0;
	409	}
	410
507a3ea7	411	static int lcd_resume(struct usb_interface *intf)
7bbe990c ON	412	{
	413	return 0;
	414	}
	415
1da177e4 LT	416	static void lcd_disconnect(struct usb_interface *interface)
1da177e4 LT	417	{
61991d02	418	struct usb_lcd *dev = usb_get_intfdata(interface);
507a3ea7	419	int minor = interface->minor;
1da177e4	420
507a3ea7 ZP	421	/* give back our minor */
	422	usb_deregister_dev(interface, &lcd_class);
	423
eb7f5a49 JH	424	down_write(&dev->io_rwsem);
	425	dev->disconnected = 1;
	426	up_write(&dev->io_rwsem);
	427
	428	usb_kill_anchored_urbs(&dev->submitted);
	429
1da177e4 LT	430	/* decrement our usage count */
	431	kref_put(&dev->kref, lcd_delete);
	432
1b29a375	433	dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
1da177e4 LT	434	}
	435
	436	static struct usb_driver lcd_driver = {
1da177e4 LT	437	.name = "usblcd",
	438	.probe = lcd_probe,
	439	.disconnect = lcd_disconnect,
7bbe990c ON	440	.suspend = lcd_suspend,
7bbe990c ON	441	.resume = lcd_resume,
1da177e4	442	.id_table = id_table,
7bbe990c	443	.supports_autosuspend = 1,
1da177e4 LT	444	};
1da177e4 LT	445
65db4305	446	module_usb_driver(lcd_driver);
1da177e4 LT	447
	448	MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
	449	MODULE_DESCRIPTION(DRIVER_VERSION);
	450	MODULE_LICENSE("GPL");