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