// 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_obj(*dev);	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");