drivers/media/radio/radio-mr800.c

   1 /*
   2  * A driver for the AverMedia MR 800 USB FM radio. This device plugs
   3  * into both the USB and an analog audio input, so this thing
   4  * only deals with initialization and frequency setting, the
   5  * audio data has to be handled by a sound driver.
   6  *
   7  * Copyright (c) 2008 Alexey Klimov <klimov.linux@gmail.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23
  24 /*
  25  * Big thanks to authors and contributors of dsbr100.c and radio-si470x.c
  26  *
  27  * When work was looked pretty good, i discover this:
  28  * http://av-usbradio.sourceforge.net/index.php
  29  * http://sourceforge.net/projects/av-usbradio/
  30  * Latest release of theirs project was in 2005.
  31  * Probably, this driver could be improved trough using their
  32  * achievements (specifications given).
  33  * Also, Faidon Liambotis <paravoid@debian.org> wrote nice driver for this radio
  34  * in 2007. He allowed to use his driver to improve current mr800 radio driver.
  35  * http://kerneltrap.org/mailarchive/linux-usb-devel/2007/10/11/342492
  36  *
  37  * Version 0.01:        First working version.
  38  *                      It's required to blacklist AverMedia USB Radio
  39  *                      in usbhid/hid-quirks.c
  40  * Version 0.10:        A lot of cleanups and fixes: unpluging the device,
  41  *                      few mutex locks were added, codinstyle issues, etc.
  42  *                      Added stereo support. Thanks to
  43  *                      Douglas Schilling Landgraf <dougsland@gmail.com> and
  44  *                      David Ellingsworth <david@identd.dyndns.org>
  45  *                      for discussion, help and support.
  46  * Version 0.11:        Converted to v4l2_device.
  47  *
  48  * Many things to do:
  49  *      - Correct power management of device (suspend & resume)
  50  *      - Add code for scanning and smooth tuning
  51  *      - Add code for sensitivity value
  52  *      - Correct mistakes
  53  *      - In Japan another FREQ_MIN and FREQ_MAX
  54  */
  55
  56 /* kernel includes */
  57 #include <linux/kernel.h>
  58 #include <linux/module.h>
  59 #include <linux/init.h>
  60 #include <linux/slab.h>
  61 #include <linux/smp_lock.h>
  62 #include <linux/input.h>
  63 #include <linux/videodev2.h>
  64 #include <media/v4l2-device.h>
  65 #include <media/v4l2-ioctl.h>
  66 #include <linux/usb.h>
  67 #include <linux/version.h>      /* for KERNEL_VERSION MACRO */
  68 #include <linux/mutex.h>
  69
  70 /* driver and module definitions */
  71 #define DRIVER_AUTHOR "Alexey Klimov <klimov.linux@gmail.com>"
  72 #define DRIVER_DESC "AverMedia MR 800 USB FM radio driver"
  73 #define DRIVER_VERSION "0.11"
  74 #define RADIO_VERSION KERNEL_VERSION(0, 1, 1)
  75
  76 MODULE_AUTHOR(DRIVER_AUTHOR);
  77 MODULE_DESCRIPTION(DRIVER_DESC);
  78 MODULE_LICENSE("GPL");
  79
  80 #define USB_AMRADIO_VENDOR 0x07ca
  81 #define USB_AMRADIO_PRODUCT 0xb800
  82
  83 /* dev_warn macro with driver name */
  84 #define MR800_DRIVER_NAME "radio-mr800"
  85 #define amradio_dev_warn(dev, fmt, arg...)                              \
  86                 dev_warn(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
  87
  88 #define amradio_dev_err(dev, fmt, arg...) \
  89                 dev_err(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
  90
  91 /* Probably USB_TIMEOUT should be modified in module parameter */
  92 #define BUFFER_LENGTH 8
  93 #define USB_TIMEOUT 500
  94
  95 /* Frequency limits in MHz -- these are European values.  For Japanese
  96 devices, that would be 76 and 91.  */
  97 #define FREQ_MIN  87.5
  98 #define FREQ_MAX 108.0
  99 #define FREQ_MUL 16000
 100
 101 /*
 102  * Commands that device should understand
 103  * List isnt full and will be updated with implementation of new functions
 104  */
 105 #define AMRADIO_SET_FREQ        0xa4
 106 #define AMRADIO_SET_MUTE        0xab
 107 #define AMRADIO_SET_MONO        0xae
 108
 109 /* Comfortable defines for amradio_set_mute */
 110 #define AMRADIO_START           0x00
 111 #define AMRADIO_STOP            0x01
 112
 113 /* Comfortable defines for amradio_set_stereo */
 114 #define WANT_STEREO             0x00
 115 #define WANT_MONO               0x01
 116
 117 /* module parameter */
 118 static int radio_nr = -1;
 119 module_param(radio_nr, int, 0);
 120 MODULE_PARM_DESC(radio_nr, "Radio Nr");
 121
 122 static int usb_amradio_probe(struct usb_interface *intf,
 123                              const struct usb_device_id *id);
 124 static void usb_amradio_disconnect(struct usb_interface *intf);
 125 static int usb_amradio_open(struct file *file);
 126 static int usb_amradio_close(struct file *file);
 127 static int usb_amradio_suspend(struct usb_interface *intf,
 128                                 pm_message_t message);
 129 static int usb_amradio_resume(struct usb_interface *intf);
 130
 131 /* Data for one (physical) device */
 132 struct amradio_device {
 133         /* reference to USB and video device */
 134         struct usb_device *usbdev;
 135         struct video_device videodev;
 136         struct v4l2_device v4l2_dev;
 137
 138         unsigned char *buffer;
 139         struct mutex lock;      /* buffer locking */
 140         int curfreq;
 141         int stereo;
 142         int muted;
 143         int initialized;
 144 };
 145
 146 #define vdev_to_amradio(r) container_of(r, struct amradio_device, videodev)
 147
 148 /* USB Device ID List */
 149 static struct usb_device_id usb_amradio_device_table[] = {
 150         {USB_DEVICE_AND_INTERFACE_INFO(USB_AMRADIO_VENDOR, USB_AMRADIO_PRODUCT,
 151                                                         USB_CLASS_HID, 0, 0) },
 152         { }                                             /* Terminating entry */
 153 };
 154
 155 MODULE_DEVICE_TABLE(usb, usb_amradio_device_table);
 156
 157 /* USB subsystem interface */
 158 static struct usb_driver usb_amradio_driver = {
 159         .name                   = MR800_DRIVER_NAME,
 160         .probe                  = usb_amradio_probe,
 161         .disconnect             = usb_amradio_disconnect,
 162         .suspend                = usb_amradio_suspend,
 163         .resume                 = usb_amradio_resume,
 164         .reset_resume           = usb_amradio_resume,
 165         .id_table               = usb_amradio_device_table,
 166         .supports_autosuspend   = 0,
 167 };
 168
 169 /* switch on/off the radio. Send 8 bytes to device */
 170 static int amradio_set_mute(struct amradio_device *radio, char argument)
 171 {
 172         int retval;
 173         int size;
 174
 175         BUG_ON(!mutex_is_locked(&radio->lock));
 176
 177         radio->buffer[0] = 0x00;
 178         radio->buffer[1] = 0x55;
 179         radio->buffer[2] = 0xaa;
 180         radio->buffer[3] = 0x00;
 181         radio->buffer[4] = AMRADIO_SET_MUTE;
 182         radio->buffer[5] = argument;
 183         radio->buffer[6] = 0x00;
 184         radio->buffer[7] = 0x00;
 185
 186         retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 187                 (void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
 188
 189         if (retval < 0 || size != BUFFER_LENGTH) {
 190                 amradio_dev_warn(&radio->videodev.dev, "set mute failed\n");
 191                 return retval;
 192         }
 193
 194         radio->muted = argument;
 195
 196         return retval;
 197 }
 198
 199 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
 200 static int amradio_setfreq(struct amradio_device *radio, int freq)
 201 {
 202         int retval;
 203         int size;
 204         unsigned short freq_send = 0x10 + (freq >> 3) / 25;
 205
 206         BUG_ON(!mutex_is_locked(&radio->lock));
 207
 208         radio->buffer[0] = 0x00;
 209         radio->buffer[1] = 0x55;
 210         radio->buffer[2] = 0xaa;
 211         radio->buffer[3] = 0x03;
 212         radio->buffer[4] = AMRADIO_SET_FREQ;
 213         radio->buffer[5] = 0x00;
 214         radio->buffer[6] = 0x00;
 215         radio->buffer[7] = 0x08;
 216
 217         retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 218                 (void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
 219
 220         if (retval < 0 || size != BUFFER_LENGTH)
 221                 goto out_err;
 222
 223         /* frequency is calculated from freq_send and placed in first 2 bytes */
 224         radio->buffer[0] = (freq_send >> 8) & 0xff;
 225         radio->buffer[1] = freq_send & 0xff;
 226         radio->buffer[2] = 0x01;
 227         radio->buffer[3] = 0x00;
 228         radio->buffer[4] = 0x00;
 229         /* 5 and 6 bytes of buffer already = 0x00 */
 230         radio->buffer[7] = 0x00;
 231
 232         retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 233                 (void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
 234
 235         if (retval < 0 || size != BUFFER_LENGTH)
 236                 goto out_err;
 237
 238         goto out;
 239
 240 out_err:
 241         amradio_dev_warn(&radio->videodev.dev, "set frequency failed\n");
 242 out:
 243         return retval;
 244 }
 245
 246 static int amradio_set_stereo(struct amradio_device *radio, char argument)
 247 {
 248         int retval;
 249         int size;
 250
 251         BUG_ON(!mutex_is_locked(&radio->lock));
 252
 253         radio->buffer[0] = 0x00;
 254         radio->buffer[1] = 0x55;
 255         radio->buffer[2] = 0xaa;
 256         radio->buffer[3] = 0x00;
 257         radio->buffer[4] = AMRADIO_SET_MONO;
 258         radio->buffer[5] = argument;
 259         radio->buffer[6] = 0x00;
 260         radio->buffer[7] = 0x00;
 261
 262         retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 263                 (void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);
 264
 265         if (retval < 0 || size != BUFFER_LENGTH) {
 266                 amradio_dev_warn(&radio->videodev.dev, "set stereo failed\n");
 267                 return retval;
 268         }
 269
 270         if (argument == WANT_STEREO)
 271                 radio->stereo = 1;
 272         else
 273                 radio->stereo = 0;
 274
 275         return retval;
 276 }
 277
 278 /* Handle unplugging the device.
 279  * We call video_unregister_device in any case.
 280  * The last function called in this procedure is
 281  * usb_amradio_device_release.
 282  */
 283 static void usb_amradio_disconnect(struct usb_interface *intf)
 284 {
 285         struct amradio_device *radio = usb_get_intfdata(intf);
 286
 287         mutex_lock(&radio->lock);
 288         radio->usbdev = NULL;
 289         mutex_unlock(&radio->lock);
 290
 291         usb_set_intfdata(intf, NULL);
 292         v4l2_device_disconnect(&radio->v4l2_dev);
 293         video_unregister_device(&radio->videodev);
 294 }
 295
 296 /* vidioc_querycap - query device capabilities */
 297 static int vidioc_querycap(struct file *file, void *priv,
 298                                         struct v4l2_capability *v)
 299 {
 300         struct amradio_device *radio = file->private_data;
 301
 302         strlcpy(v->driver, "radio-mr800", sizeof(v->driver));
 303         strlcpy(v->card, "AverMedia MR 800 USB FM Radio", sizeof(v->card));
 304         usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
 305         v->version = RADIO_VERSION;
 306         v->capabilities = V4L2_CAP_TUNER;
 307         return 0;
 308 }
 309
 310 /* vidioc_g_tuner - get tuner attributes */
 311 static int vidioc_g_tuner(struct file *file, void *priv,
 312                                 struct v4l2_tuner *v)
 313 {
 314         struct amradio_device *radio = file->private_data;
 315         int retval;
 316
 317         if (v->index > 0)
 318                 return -EINVAL;
 319
 320 /* TODO: Add function which look is signal stereo or not
 321  *      amradio_getstat(radio);
 322  */
 323
 324 /* we call amradio_set_stereo to set radio->stereo
 325  * Honestly, amradio_getstat should cover this in future and
 326  * amradio_set_stereo shouldn't be here
 327  */
 328         retval = amradio_set_stereo(radio, WANT_STEREO);
 329
 330         strcpy(v->name, "FM");
 331         v->type = V4L2_TUNER_RADIO;
 332         v->rangelow = FREQ_MIN * FREQ_MUL;
 333         v->rangehigh = FREQ_MAX * FREQ_MUL;
 334         v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
 335         v->capability = V4L2_TUNER_CAP_LOW;
 336         if (radio->stereo)
 337                 v->audmode = V4L2_TUNER_MODE_STEREO;
 338         else
 339                 v->audmode = V4L2_TUNER_MODE_MONO;
 340         v->signal = 0xffff;     /* Can't get the signal strength, sad.. */
 341         v->afc = 0; /* Don't know what is this */
 342
 343         return retval;
 344 }
 345
 346 /* vidioc_s_tuner - set tuner attributes */
 347 static int vidioc_s_tuner(struct file *file, void *priv,
 348                                 struct v4l2_tuner *v)
 349 {
 350         struct amradio_device *radio = file->private_data;
 351         int retval = -EINVAL;
 352
 353         if (v->index > 0)
 354                 return -EINVAL;
 355
 356         /* mono/stereo selector */
 357         switch (v->audmode) {
 358         case V4L2_TUNER_MODE_MONO:
 359                 retval = amradio_set_stereo(radio, WANT_MONO);
 360                 break;
 361         case V4L2_TUNER_MODE_STEREO:
 362                 retval = amradio_set_stereo(radio, WANT_STEREO);
 363                 break;
 364         }
 365
 366         return retval;
 367 }
 368
 369 /* vidioc_s_frequency - set tuner radio frequency */
 370 static int vidioc_s_frequency(struct file *file, void *priv,
 371                                 struct v4l2_frequency *f)
 372 {
 373         struct amradio_device *radio = file->private_data;
 374         int retval = 0;
 375
 376         radio->curfreq = f->frequency;
 377
 378         retval = amradio_setfreq(radio, radio->curfreq);
 379
 380         return retval;
 381 }
 382
 383 /* vidioc_g_frequency - get tuner radio frequency */
 384 static int vidioc_g_frequency(struct file *file, void *priv,
 385                                 struct v4l2_frequency *f)
 386 {
 387         struct amradio_device *radio = file->private_data;
 388
 389         f->type = V4L2_TUNER_RADIO;
 390         f->frequency = radio->curfreq;
 391
 392         return 0;
 393 }
 394
 395 /* vidioc_queryctrl - enumerate control items */
 396 static int vidioc_queryctrl(struct file *file, void *priv,
 397                                 struct v4l2_queryctrl *qc)
 398 {
 399         switch (qc->id) {
 400         case V4L2_CID_AUDIO_MUTE:
 401                 return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
 402         }
 403
 404         return -EINVAL;
 405 }
 406
 407 /* vidioc_g_ctrl - get the value of a control */
 408 static int vidioc_g_ctrl(struct file *file, void *priv,
 409                                 struct v4l2_control *ctrl)
 410 {
 411         struct amradio_device *radio = file->private_data;
 412
 413         switch (ctrl->id) {
 414         case V4L2_CID_AUDIO_MUTE:
 415                 ctrl->value = radio->muted;
 416                 return 0;
 417         }
 418
 419         return -EINVAL;
 420 }
 421
 422 /* vidioc_s_ctrl - set the value of a control */
 423 static int vidioc_s_ctrl(struct file *file, void *priv,
 424                                 struct v4l2_control *ctrl)
 425 {
 426         struct amradio_device *radio = file->private_data;
 427         int retval = -EINVAL;
 428
 429         switch (ctrl->id) {
 430         case V4L2_CID_AUDIO_MUTE:
 431                 if (ctrl->value)
 432                         retval = amradio_set_mute(radio, AMRADIO_STOP);
 433                 else
 434                         retval = amradio_set_mute(radio, AMRADIO_START);
 435
 436                 break;
 437         }
 438
 439         return retval;
 440 }
 441
 442 /* vidioc_g_audio - get audio attributes */
 443 static int vidioc_g_audio(struct file *file, void *priv,
 444                                 struct v4l2_audio *a)
 445 {
 446         if (a->index > 1)
 447                 return -EINVAL;
 448
 449         strcpy(a->name, "Radio");
 450         a->capability = V4L2_AUDCAP_STEREO;
 451         return 0;
 452 }
 453
 454 /* vidioc_s_audio - set audio attributes  */
 455 static int vidioc_s_audio(struct file *file, void *priv,
 456                                         struct v4l2_audio *a)
 457 {
 458         if (a->index != 0)
 459                 return -EINVAL;
 460         return 0;
 461 }
 462
 463 /* vidioc_g_input - get input */
 464 static int vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
 465 {
 466         *i = 0;
 467         return 0;
 468 }
 469
 470 /* vidioc_s_input - set input */
 471 static int vidioc_s_input(struct file *filp, void *priv, unsigned int i)
 472 {
 473         if (i != 0)
 474                 return -EINVAL;
 475         return 0;
 476 }
 477
 478 static int usb_amradio_init(struct amradio_device *radio)
 479 {
 480         int retval;
 481
 482         retval = amradio_set_mute(radio, AMRADIO_STOP);
 483         if (retval)
 484                 goto out_err;
 485
 486         retval = amradio_set_stereo(radio, WANT_STEREO);
 487         if (retval)
 488                 goto out_err;
 489
 490         radio->initialized = 1;
 491         goto out;
 492
 493 out_err:
 494         amradio_dev_err(&radio->videodev.dev, "initialization failed\n");
 495 out:
 496         return retval;
 497 }
 498
 499 /* open device - amradio_start() and amradio_setfreq() */
 500 static int usb_amradio_open(struct file *file)
 501 {
 502         struct amradio_device *radio = vdev_to_amradio(video_devdata(file));
 503         int retval = 0;
 504
 505         mutex_lock(&radio->lock);
 506
 507         if (!radio->usbdev) {
 508                 retval = -EIO;
 509                 goto unlock;
 510         }
 511
 512         file->private_data = radio;
 513
 514         if (unlikely(!radio->initialized))
 515                 retval = usb_amradio_init(radio);
 516
 517 unlock:
 518         mutex_unlock(&radio->lock);
 519         return retval;
 520 }
 521
 522 /*close device */
 523 static int usb_amradio_close(struct file *file)
 524 {
 525         struct amradio_device *radio = file->private_data;
 526         int retval = 0;
 527
 528         mutex_lock(&radio->lock);
 529
 530         if (!radio->usbdev)
 531                 retval = -EIO;
 532
 533         mutex_unlock(&radio->lock);
 534         return retval;
 535 }
 536
 537 static long usb_amradio_ioctl(struct file *file, unsigned int cmd,
 538                                 unsigned long arg)
 539 {
 540         struct amradio_device *radio = file->private_data;
 541         long retval = 0;
 542
 543         mutex_lock(&radio->lock);
 544
 545         if (!radio->usbdev) {
 546                 retval = -EIO;
 547                 goto unlock;
 548         }
 549
 550         retval = video_ioctl2(file, cmd, arg);
 551
 552 unlock:
 553         mutex_unlock(&radio->lock);
 554         return retval;
 555 }
 556
 557 /* Suspend device - stop device. Need to be checked and fixed */
 558 static int usb_amradio_suspend(struct usb_interface *intf, pm_message_t message)
 559 {
 560         struct amradio_device *radio = usb_get_intfdata(intf);
 561
 562         mutex_lock(&radio->lock);
 563
 564         if (!radio->muted && radio->initialized) {
 565                 amradio_set_mute(radio, AMRADIO_STOP);
 566                 radio->muted = 0;
 567         }
 568
 569         dev_info(&intf->dev, "going into suspend..\n");
 570
 571         mutex_unlock(&radio->lock);
 572         return 0;
 573 }
 574
 575 /* Resume device - start device. Need to be checked and fixed */
 576 static int usb_amradio_resume(struct usb_interface *intf)
 577 {
 578         struct amradio_device *radio = usb_get_intfdata(intf);
 579
 580         mutex_lock(&radio->lock);
 581
 582         if (unlikely(!radio->initialized))
 583                 goto unlock;
 584
 585         if (radio->stereo)
 586                 amradio_set_stereo(radio, WANT_STEREO);
 587         else
 588                 amradio_set_stereo(radio, WANT_MONO);
 589
 590         amradio_setfreq(radio, radio->curfreq);
 591
 592         if (!radio->muted)
 593                 amradio_set_mute(radio, AMRADIO_START);
 594
 595 unlock:
 596         dev_info(&intf->dev, "coming out of suspend..\n");
 597
 598         mutex_unlock(&radio->lock);
 599         return 0;
 600 }
 601
 602 /* File system interface */
 603 static const struct v4l2_file_operations usb_amradio_fops = {
 604         .owner          = THIS_MODULE,
 605         .open           = usb_amradio_open,
 606         .release        = usb_amradio_close,
 607         .ioctl          = usb_amradio_ioctl,
 608 };
 609
 610 static const struct v4l2_ioctl_ops usb_amradio_ioctl_ops = {
 611         .vidioc_querycap    = vidioc_querycap,
 612         .vidioc_g_tuner     = vidioc_g_tuner,
 613         .vidioc_s_tuner     = vidioc_s_tuner,
 614         .vidioc_g_frequency = vidioc_g_frequency,
 615         .vidioc_s_frequency = vidioc_s_frequency,
 616         .vidioc_queryctrl   = vidioc_queryctrl,
 617         .vidioc_g_ctrl      = vidioc_g_ctrl,
 618         .vidioc_s_ctrl      = vidioc_s_ctrl,
 619         .vidioc_g_audio     = vidioc_g_audio,
 620         .vidioc_s_audio     = vidioc_s_audio,
 621         .vidioc_g_input     = vidioc_g_input,
 622         .vidioc_s_input     = vidioc_s_input,
 623 };
 624
 625 static void usb_amradio_video_device_release(struct video_device *videodev)
 626 {
 627         struct amradio_device *radio = vdev_to_amradio(videodev);
 628
 629         v4l2_device_unregister(&radio->v4l2_dev);
 630
 631         /* free rest memory */
 632         kfree(radio->buffer);
 633         kfree(radio);
 634 }
 635
 636 /* check if the device is present and register with v4l and usb if it is */
 637 static int usb_amradio_probe(struct usb_interface *intf,
 638                                 const struct usb_device_id *id)
 639 {
 640         struct amradio_device *radio;
 641         int retval = 0;
 642
 643         radio = kzalloc(sizeof(struct amradio_device), GFP_KERNEL);
 644
 645         if (!radio) {
 646                 dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
 647                 retval = -ENOMEM;
 648                 goto err;
 649         }
 650
 651         radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
 652
 653         if (!radio->buffer) {
 654                 dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
 655                 retval = -ENOMEM;
 656                 goto err_nobuf;
 657         }
 658
 659         retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
 660         if (retval < 0) {
 661                 dev_err(&intf->dev, "couldn't register v4l2_device\n");
 662                 goto err_v4l2;
 663         }
 664
 665         strlcpy(radio->videodev.name, radio->v4l2_dev.name,
 666                 sizeof(radio->videodev.name));
 667         radio->videodev.v4l2_dev = &radio->v4l2_dev;
 668         radio->videodev.fops = &usb_amradio_fops;
 669         radio->videodev.ioctl_ops = &usb_amradio_ioctl_ops;
 670         radio->videodev.release = usb_amradio_video_device_release;
 671
 672         radio->usbdev = interface_to_usbdev(intf);
 673         radio->curfreq = 95.16 * FREQ_MUL;
 674
 675         mutex_init(&radio->lock);
 676
 677         video_set_drvdata(&radio->videodev, radio);
 678
 679         retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO,
 680                                         radio_nr);
 681         if (retval < 0) {
 682                 dev_err(&intf->dev, "could not register video device\n");
 683                 goto err_vdev;
 684         }
 685
 686         usb_set_intfdata(intf, radio);
 687         return 0;
 688
 689 err_vdev:
 690         v4l2_device_unregister(&radio->v4l2_dev);
 691 err_v4l2:
 692         kfree(radio->buffer);
 693 err_nobuf:
 694         kfree(radio);
 695 err:
 696         return retval;
 697 }
 698
 699 static int __init amradio_init(void)
 700 {
 701         int retval = usb_register(&usb_amradio_driver);
 702
 703         pr_info(KBUILD_MODNAME
 704                 ": version " DRIVER_VERSION " " DRIVER_DESC "\n");
 705
 706         if (retval)
 707                 pr_err(KBUILD_MODNAME
 708                         ": usb_register failed. Error number %d\n", retval);
 709
 710         return retval;
 711 }
 712
 713 static void __exit amradio_exit(void)
 714 {
 715         usb_deregister(&usb_amradio_driver);
 716 }
 717
 718 module_init(amradio_init);
 719 module_exit(amradio_exit);
 720