drivers/usb/misc/usblcd.c

   1 /*****************************************************************************
   2  *                          USBLCD Kernel Driver                             *
   3  *                            Version 1.05                                   *
   4  *             (C) 2005 Georges Toth <g.toth@e-biz.lu>                       *
   5  *                                                                           *
   6  *     This file is licensed under the GPL. See COPYING in the package.      *
   7  * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com)        *
   8  *                                                                           *
   9  *                                                                           *
  10  * 28.02.05 Complete rewrite of the original usblcd.c driver,                *
  11  *          based on usb_skeleton.c.                                         *
  12  *          This new driver allows more than one USB-LCD to be connected     *
  13  *          and controlled, at once                                          *
  14  *****************************************************************************/
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/errno.h>
  20 #include <asm/uaccess.h>
  21 #include <linux/usb.h>
  22
  23 #define DRIVER_VERSION "USBLCD Driver Version 1.05"
  24
  25 #define USBLCD_MINOR            144
  26
  27 #define IOCTL_GET_HARD_VERSION  1
  28 #define IOCTL_GET_DRV_VERSION   2
  29
  30
  31 static struct usb_device_id id_table [] = {
  32         { .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
  33         { },
  34 };
  35 MODULE_DEVICE_TABLE (usb, id_table);
  36
  37
  38 struct usb_lcd {
  39         struct usb_device *     udev;                   /* init: probe_lcd */
  40         struct usb_interface *  interface;              /* the interface for this device */
  41         unsigned char *         bulk_in_buffer;         /* the buffer to receive data */
  42         size_t                  bulk_in_size;           /* the size of the receive buffer */
  43         __u8                    bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
  44         __u8                    bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
  45         struct kref             kref;
  46 };
  47 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
  48
  49 static struct usb_driver lcd_driver;
  50
  51
  52 static void lcd_delete(struct kref *kref)
  53 {
  54         struct usb_lcd *dev = to_lcd_dev(kref);
  55
  56         usb_put_dev(dev->udev);
  57         kfree (dev->bulk_in_buffer);
  58         kfree (dev);
  59 }
  60
  61
  62 static int lcd_open(struct inode *inode, struct file *file)
  63 {
  64         struct usb_lcd *dev;
  65         struct usb_interface *interface;
  66         int subminor;
  67         int retval = 0;
  68
  69         subminor = iminor(inode);
  70
  71         interface = usb_find_interface(&lcd_driver, subminor);
  72         if (!interface) {
  73                 err ("USBLCD: %s - error, can't find device for minor %d",
  74                      __FUNCTION__, subminor);
  75                 retval = -ENODEV;
  76                 goto exit;
  77         }
  78
  79         dev = usb_get_intfdata(interface);
  80         if (!dev) {
  81                 retval = -ENODEV;
  82                 goto exit;
  83         }
  84
  85         /* increment our usage count for the device */
  86         kref_get(&dev->kref);
  87
  88         /* save our object in the file's private structure */
  89         file->private_data = dev;
  90
  91 exit:
  92         return retval;
  93 }
  94
  95 static int lcd_release(struct inode *inode, struct file *file)
  96 {
  97         struct usb_lcd *dev;
  98
  99         dev = (struct usb_lcd *)file->private_data;
 100         if (dev == NULL)
 101                 return -ENODEV;
 102
 103         /* decrement the count on our device */
 104         kref_put(&dev->kref, lcd_delete);
 105         return 0;
 106 }
 107
 108 static ssize_t lcd_read(struct file *file, char __user * buffer, size_t count, loff_t *ppos)
 109 {
 110         struct usb_lcd *dev;
 111         int retval = 0;
 112         int bytes_read;
 113
 114         dev = (struct usb_lcd *)file->private_data;
 115
 116         /* do a blocking bulk read to get data from the device */
 117         retval = usb_bulk_msg(dev->udev,
 118                               usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
 119                               dev->bulk_in_buffer,
 120                               min(dev->bulk_in_size, count),
 121                               &bytes_read, 10000);
 122
 123         /* if the read was successful, copy the data to userspace */
 124         if (!retval) {
 125                 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
 126                         retval = -EFAULT;
 127                 else
 128                         retval = bytes_read;
 129         }
 130
 131         return retval;
 132 }
 133
 134 static int lcd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 135 {
 136         struct usb_lcd *dev;
 137         u16 bcdDevice;
 138         char buf[30];
 139
 140         dev = (struct usb_lcd *)file->private_data;
 141         if (dev == NULL)
 142                 return -ENODEV;
 143
 144         switch (cmd) {
 145         case IOCTL_GET_HARD_VERSION:
 146                 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
 147                 sprintf(buf,"%1d%1d.%1d%1d",
 148                         (bcdDevice & 0xF000)>>12,
 149                         (bcdDevice & 0xF00)>>8,
 150                         (bcdDevice & 0xF0)>>4,
 151                         (bcdDevice & 0xF));
 152                 if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
 153                         return -EFAULT;
 154                 break;
 155         case IOCTL_GET_DRV_VERSION:
 156                 sprintf(buf,DRIVER_VERSION);
 157                 if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
 158                         return -EFAULT;
 159                 break;
 160         default:
 161                 return -ENOTTY;
 162                 break;
 163         }
 164
 165         return 0;
 166 }
 167
 168 static void lcd_write_bulk_callback(struct urb *urb)
 169 {
 170         struct usb_lcd *dev;
 171
 172         dev = (struct usb_lcd *)urb->context;
 173
 174         /* sync/async unlink faults aren't errors */
 175         if (urb->status &&
 176             !(urb->status == -ENOENT ||
 177               urb->status == -ECONNRESET ||
 178               urb->status == -ESHUTDOWN)) {
 179                 dbg("USBLCD: %s - nonzero write bulk status received: %d",
 180                     __FUNCTION__, urb->status);
 181         }
 182
 183         /* free up our allocated buffer */
 184         usb_buffer_free(urb->dev, urb->transfer_buffer_length,
 185                         urb->transfer_buffer, urb->transfer_dma);
 186 }
 187
 188 static ssize_t lcd_write(struct file *file, const char __user * user_buffer, size_t count, loff_t *ppos)
 189 {
 190         struct usb_lcd *dev;
 191         int retval = 0;
 192         struct urb *urb = NULL;
 193         char *buf = NULL;
 194
 195         dev = (struct usb_lcd *)file->private_data;
 196
 197         /* verify that we actually have some data to write */
 198         if (count == 0)
 199                 goto exit;
 200
 201         /* create a urb, and a buffer for it, and copy the data to the urb */
 202         urb = usb_alloc_urb(0, GFP_KERNEL);
 203         if (!urb)
 204                 return -ENOMEM;
 205
 206         buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
 207         if (!buf) {
 208                 retval = -ENOMEM;
 209                 goto error;
 210         }
 211
 212         if (copy_from_user(buf, user_buffer, count)) {
 213                 retval = -EFAULT;
 214                 goto error;
 215         }
 216
 217         /* initialize the urb properly */
 218         usb_fill_bulk_urb(urb, dev->udev,
 219                           usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
 220                           buf, count, lcd_write_bulk_callback, dev);
 221         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 222
 223         /* send the data out the bulk port */
 224         retval = usb_submit_urb(urb, GFP_KERNEL);
 225         if (retval) {
 226                 err("USBLCD: %s - failed submitting write urb, error %d", __FUNCTION__, retval);
 227                 goto error;
 228         }
 229
 230         /* release our reference to this urb, the USB core will eventually free it entirely */
 231         usb_free_urb(urb);
 232
 233 exit:
 234         return count;
 235
 236 error:
 237         usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
 238         usb_free_urb(urb);
 239         return retval;
 240 }
 241
 242 static const struct file_operations lcd_fops = {
 243         .owner =        THIS_MODULE,
 244         .read =         lcd_read,
 245         .write =        lcd_write,
 246         .open =         lcd_open,
 247         .ioctl =        lcd_ioctl,
 248         .release =      lcd_release,
 249 };
 250
 251 /*
 252  * usb class driver info in order to get a minor number from the usb core,
 253  * and to have the device registered with the driver core
 254  */
 255 static struct usb_class_driver lcd_class = {
 256         .name =         "lcd%d",
 257         .fops =         &lcd_fops,
 258         .minor_base =   USBLCD_MINOR,
 259 };
 260
 261 static int lcd_probe(struct usb_interface *interface, const struct usb_device_id *id)
 262 {
 263         struct usb_lcd *dev = NULL;
 264         struct usb_host_interface *iface_desc;
 265         struct usb_endpoint_descriptor *endpoint;
 266         size_t buffer_size;
 267         int i;
 268         int retval = -ENOMEM;
 269
 270         /* allocate memory for our device state and initialize it */
 271         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 272         if (dev == NULL) {
 273                 err("Out of memory");
 274                 goto error;
 275         }
 276         kref_init(&dev->kref);
 277
 278         dev->udev = usb_get_dev(interface_to_usbdev(interface));
 279         dev->interface = interface;
 280
 281         if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
 282                 warn(KERN_INFO "USBLCD model not supported.");
 283                 return -ENODEV;
 284         }
 285
 286         /* set up the endpoint information */
 287         /* use only the first bulk-in and bulk-out endpoints */
 288         iface_desc = interface->cur_altsetting;
 289         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 290                 endpoint = &iface_desc->endpoint[i].desc;
 291
 292                 if (!dev->bulk_in_endpointAddr &&
 293                     usb_endpoint_is_bulk_in(endpoint)) {
 294                         /* we found a bulk in endpoint */
 295                         buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
 296                         dev->bulk_in_size = buffer_size;
 297                         dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
 298                         dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
 299                         if (!dev->bulk_in_buffer) {
 300                                 err("Could not allocate bulk_in_buffer");
 301                                 goto error;
 302                         }
 303                 }
 304
 305                 if (!dev->bulk_out_endpointAddr &&
 306                     usb_endpoint_is_bulk_out(endpoint)) {
 307                         /* we found a bulk out endpoint */
 308                         dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
 309                 }
 310         }
 311         if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
 312                 err("Could not find both bulk-in and bulk-out endpoints");
 313                 goto error;
 314         }
 315
 316         /* save our data pointer in this interface device */
 317         usb_set_intfdata(interface, dev);
 318
 319         /* we can register the device now, as it is ready */
 320         retval = usb_register_dev(interface, &lcd_class);
 321         if (retval) {
 322                 /* something prevented us from registering this driver */
 323                 err("Not able to get a minor for this device.");
 324                 usb_set_intfdata(interface, NULL);
 325                 goto error;
 326         }
 327
 328         i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
 329
 330         info("USBLCD Version %1d%1d.%1d%1d found at address %d",
 331                 (i & 0xF000)>>12,(i & 0xF00)>>8,(i & 0xF0)>>4,(i & 0xF),
 332                 dev->udev->devnum);
 333
 334         /* let the user know what node this device is now attached to */
 335         info("USB LCD device now attached to USBLCD-%d", interface->minor);
 336         return 0;
 337
 338 error:
 339         if (dev)
 340                 kref_put(&dev->kref, lcd_delete);
 341         return retval;
 342 }
 343
 344 static void lcd_disconnect(struct usb_interface *interface)
 345 {
 346         struct usb_lcd *dev;
 347         int minor = interface->minor;
 348
 349         /* prevent skel_open() from racing skel_disconnect() */
 350         lock_kernel();
 351
 352         dev = usb_get_intfdata(interface);
 353         usb_set_intfdata(interface, NULL);
 354
 355         /* give back our minor */
 356         usb_deregister_dev(interface, &lcd_class);
 357
 358         unlock_kernel();
 359
 360         /* decrement our usage count */
 361         kref_put(&dev->kref, lcd_delete);
 362
 363         info("USB LCD #%d now disconnected", minor);
 364 }
 365
 366 static struct usb_driver lcd_driver = {
 367         .name =         "usblcd",
 368         .probe =        lcd_probe,
 369         .disconnect =   lcd_disconnect,
 370         .id_table =     id_table,
 371 };
 372
 373 static int __init usb_lcd_init(void)
 374 {
 375         int result;
 376
 377         result = usb_register(&lcd_driver);
 378         if (result)
 379                 err("usb_register failed. Error number %d", result);
 380
 381         return result;
 382 }
 383
 384
 385 static void __exit usb_lcd_exit(void)
 386 {
 387         usb_deregister(&lcd_driver);
 388 }
 389
 390 module_init(usb_lcd_init);
 391 module_exit(usb_lcd_exit);
 392
 393 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
 394 MODULE_DESCRIPTION(DRIVER_VERSION);
 395 MODULE_LICENSE("GPL");