Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
/*
 *  drivers/media/radio/si470x/radio-si470x-common.c
 *
 *  Driver for radios with Silicon Labs Si470x FM Radio Receivers
 *
 *  Copyright (c) 2009 Tobias Lorenz <tobias.lorenz@gmx.net>
 *  Copyright (c) 2012 Hans de Goede <hdegoede@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


/*
 * History:
 * 2008-01-12	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Version 1.0.0
 *		- First working version
 * 2008-01-13	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Version 1.0.1
 *		- Improved error handling, every function now returns errno
 *		- Improved multi user access (start/mute/stop)
 *		- Channel doesn't get lost anymore after start/mute/stop
 *		- RDS support added (polling mode via interrupt EP 1)
 *		- marked default module parameters with *value*
 *		- switched from bit structs to bit masks
 *		- header file cleaned and integrated
 * 2008-01-14	Tobias Lorenz <tobias.lorenz@gmx.net>
 * 		Version 1.0.2
 * 		- hex values are now lower case
 * 		- commented USB ID for ADS/Tech moved on todo list
 * 		- blacklisted si470x in hid-quirks.c
 * 		- rds buffer handling functions integrated into *_work, *_read
 * 		- rds_command in si470x_poll exchanged against simple retval
 * 		- check for firmware version 15
 * 		- code order and prototypes still remain the same
 * 		- spacing and bottom of band codes remain the same
 * 2008-01-16	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Version 1.0.3
 * 		- code reordered to avoid function prototypes
 *		- switch/case defaults are now more user-friendly
 *		- unified comment style
 *		- applied all checkpatch.pl v1.12 suggestions
 *		  except the warning about the too long lines with bit comments
 *		- renamed FMRADIO to RADIO to cut line length (checkpatch.pl)
 * 2008-01-22	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Version 1.0.4
 *		- avoid poss. locking when doing copy_to_user which may sleep
 *		- RDS is automatically activated on read now
 *		- code cleaned of unnecessary rds_commands
 *		- USB Vendor/Product ID for ADS/Tech FM Radio Receiver verified
 *		  (thanks to Guillaume RAMOUSSE)
 * 2008-01-27	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Version 1.0.5
 *		- number of seek_retries changed to tune_timeout
 *		- fixed problem with incomplete tune operations by own buffers
 *		- optimization of variables and printf types
 *		- improved error logging
 * 2008-01-31	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Oliver Neukum <oliver@neukum.org>
 *		Version 1.0.6
 *		- fixed coverity checker warnings in *_usb_driver_disconnect
 *		- probe()/open() race by correct ordering in probe()
 *		- DMA coherency rules by separate allocation of all buffers
 *		- use of endianness macros
 *		- abuse of spinlock, replaced by mutex
 *		- racy handling of timer in disconnect,
 *		  replaced by delayed_work
 *		- racy interruptible_sleep_on(),
 *		  replaced with wait_event_interruptible()
 *		- handle signals in read()
 * 2008-02-08	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Oliver Neukum <oliver@neukum.org>
 *		Version 1.0.7
 *		- usb autosuspend support
 *		- unplugging fixed
 * 2008-05-07	Tobias Lorenz <tobias.lorenz@gmx.net>
 *		Version 1.0.8
 *		- hardware frequency seek support
 *		- afc indication
 *		- more safety checks, let si470x_get_freq return errno
 *		- vidioc behavior corrected according to v4l2 spec
 * 2008-10-20	Alexey Klimov <klimov.linux@gmail.com>
 * 		- add support for KWorld USB FM Radio FM700
 * 		- blacklisted KWorld radio in hid-core.c and hid-ids.h
 * 2008-12-03	Mark Lord <mlord@pobox.com>
 *		- add support for DealExtreme USB Radio
 * 2009-01-31	Bob Ross <pigiron@gmx.com>
 *		- correction of stereo detection/setting
 *		- correction of signal strength indicator scaling
 * 2009-01-31	Rick Bronson <rick@efn.org>
 *		Tobias Lorenz <tobias.lorenz@gmx.net>
 *		- add LED status output
 *		- get HW/SW version from scratchpad
 * 2009-06-16   Edouard Lafargue <edouard@lafargue.name>
 *		Version 1.0.10
 *		- add support for interrupt mode for RDS endpoint,
 *                instead of polling.
 *                Improves RDS reception significantly
 */


/* kernel includes */
#include "radio-si470x.h"



/**************************************************************************
 * Module Parameters
 **************************************************************************/

/* Spacing (kHz) */
/* 0: 200 kHz (USA, Australia) */
/* 1: 100 kHz (Europe, Japan) */
/* 2:  50 kHz */
static unsigned short space = 2;
module_param(space, ushort, 0444);
MODULE_PARM_DESC(space, "Spacing: 0=200kHz 1=100kHz *2=50kHz*");

/* De-emphasis */
/* 0: 75 us (USA) */
/* 1: 50 us (Europe, Australia, Japan) */
static unsigned short de = 1;
module_param(de, ushort, 0444);
MODULE_PARM_DESC(de, "De-emphasis: 0=75us *1=50us*");

/* Tune timeout */
static unsigned int tune_timeout = 3000;
module_param(tune_timeout, uint, 0644);
MODULE_PARM_DESC(tune_timeout, "Tune timeout: *3000*");

/* Seek timeout */
static unsigned int seek_timeout = 5000;
module_param(seek_timeout, uint, 0644);
MODULE_PARM_DESC(seek_timeout, "Seek timeout: *5000*");

static const struct v4l2_frequency_band bands[] = {
	{
		.type = V4L2_TUNER_RADIO,
		.index = 0,
		.capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
			    V4L2_TUNER_CAP_FREQ_BANDS |
			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
			    V4L2_TUNER_CAP_HWSEEK_WRAP,
		.rangelow   =  87500 * 16,
		.rangehigh  = 108000 * 16,
		.modulation = V4L2_BAND_MODULATION_FM,
	},
	{
		.type = V4L2_TUNER_RADIO,
		.index = 1,
		.capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
			    V4L2_TUNER_CAP_FREQ_BANDS |
			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
			    V4L2_TUNER_CAP_HWSEEK_WRAP,
		.rangelow   =  76000 * 16,
		.rangehigh  = 108000 * 16,
		.modulation = V4L2_BAND_MODULATION_FM,
	},
	{
		.type = V4L2_TUNER_RADIO,
		.index = 2,
		.capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
			    V4L2_TUNER_CAP_FREQ_BANDS |
			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
			    V4L2_TUNER_CAP_HWSEEK_WRAP,
		.rangelow   =  76000 * 16,
		.rangehigh  =  90000 * 16,
		.modulation = V4L2_BAND_MODULATION_FM,
	},
};

/**************************************************************************
 * Generic Functions
 **************************************************************************/

/*
 * si470x_set_band - set the band
 */
static int si470x_set_band(struct si470x_device *radio, int band)
{
	if (radio->band == band)
		return 0;

	radio->band = band;
	radio->registers[SYSCONFIG2] &= ~SYSCONFIG2_BAND;
	radio->registers[SYSCONFIG2] |= radio->band << 6;
	return si470x_set_register(radio, SYSCONFIG2);
}

/*
 * si470x_set_chan - set the channel
 */
static int si470x_set_chan(struct si470x_device *radio, unsigned short chan)
{
	int retval;
	bool timed_out = 0;

	/* start tuning */
	radio->registers[CHANNEL] &= ~CHANNEL_CHAN;
	radio->registers[CHANNEL] |= CHANNEL_TUNE | chan;
	retval = si470x_set_register(radio, CHANNEL);
	if (retval < 0)
		goto done;

	/* wait till tune operation has completed */
	INIT_COMPLETION(radio->completion);
	retval = wait_for_completion_timeout(&radio->completion,
			msecs_to_jiffies(tune_timeout));
	if (!retval)
		timed_out = true;

	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
		dev_warn(&radio->videodev.dev, "tune does not complete\n");
	if (timed_out)
		dev_warn(&radio->videodev.dev,
			"tune timed out after %u ms\n", tune_timeout);

	/* stop tuning */
	radio->registers[CHANNEL] &= ~CHANNEL_TUNE;
	retval = si470x_set_register(radio, CHANNEL);

done:
	return retval;
}

/*
 * si470x_get_step - get channel spacing
 */
static unsigned int si470x_get_step(struct si470x_device *radio)
{
	/* Spacing (kHz) */
	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_SPACE) >> 4) {
	/* 0: 200 kHz (USA, Australia) */
	case 0:
		return 200 * 16;
	/* 1: 100 kHz (Europe, Japan) */
	case 1:
		return 100 * 16;
	/* 2:  50 kHz */
	default:
		return 50 * 16;
	};
}


/*
 * si470x_get_freq - get the frequency
 */
static int si470x_get_freq(struct si470x_device *radio, unsigned int *freq)
{
	int chan, retval;

	/* read channel */
	retval = si470x_get_register(radio, READCHAN);
	chan = radio->registers[READCHAN] & READCHAN_READCHAN;

	/* Frequency (MHz) = Spacing (kHz) x Channel + Bottom of Band (MHz) */
	*freq = chan * si470x_get_step(radio) + bands[radio->band].rangelow;

	return retval;
}


/*
 * si470x_set_freq - set the frequency
 */
int si470x_set_freq(struct si470x_device *radio, unsigned int freq)
{
	unsigned short chan;

	freq = clamp(freq, bands[radio->band].rangelow,
			   bands[radio->band].rangehigh);
	/* Chan = [ Freq (Mhz) - Bottom of Band (MHz) ] / Spacing (kHz) */
	chan = (freq - bands[radio->band].rangelow) / si470x_get_step(radio);

	return si470x_set_chan(radio, chan);
}


/*
 * si470x_set_seek - set seek
 */
static int si470x_set_seek(struct si470x_device *radio,
			   const struct v4l2_hw_freq_seek *seek)
{
	int band, retval;
	unsigned int freq;
	bool timed_out = 0;

	/* set band */
	if (seek->rangelow || seek->rangehigh) {
		for (band = 0; band < ARRAY_SIZE(bands); band++) {
			if (bands[band].rangelow  == seek->rangelow &&
			    bands[band].rangehigh == seek->rangehigh)
				break;
		}
		if (band == ARRAY_SIZE(bands))
			return -EINVAL; /* No matching band found */
	} else
		band = 1; /* If nothing is specified seek 76 - 108 Mhz */

	if (radio->band != band) {
		retval = si470x_get_freq(radio, &freq);
		if (retval)
			return retval;
		retval = si470x_set_band(radio, band);
		if (retval)
			return retval;
		retval = si470x_set_freq(radio, freq);
		if (retval)
			return retval;
	}

	/* start seeking */
	radio->registers[POWERCFG] |= POWERCFG_SEEK;
	if (seek->wrap_around)
		radio->registers[POWERCFG] &= ~POWERCFG_SKMODE;
	else
		radio->registers[POWERCFG] |= POWERCFG_SKMODE;
	if (seek->seek_upward)
		radio->registers[POWERCFG] |= POWERCFG_SEEKUP;
	else
		radio->registers[POWERCFG] &= ~POWERCFG_SEEKUP;
	retval = si470x_set_register(radio, POWERCFG);
	if (retval < 0)
		return retval;

	/* wait till tune operation has completed */
	INIT_COMPLETION(radio->completion);
	retval = wait_for_completion_timeout(&radio->completion,
			msecs_to_jiffies(seek_timeout));
	if (!retval)
		timed_out = true;

	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
		dev_warn(&radio->videodev.dev, "seek does not complete\n");
	if (radio->registers[STATUSRSSI] & STATUSRSSI_SF)
		dev_warn(&radio->videodev.dev,
			"seek failed / band limit reached\n");

	/* stop seeking */
	radio->registers[POWERCFG] &= ~POWERCFG_SEEK;
	retval = si470x_set_register(radio, POWERCFG);

	/* try again, if timed out */
	if (retval == 0 && timed_out)
		return -ENODATA;
	return retval;
}


/*
 * si470x_start - switch on radio
 */
int si470x_start(struct si470x_device *radio)
{
	int retval;

	/* powercfg */
	radio->registers[POWERCFG] =
		POWERCFG_DMUTE | POWERCFG_ENABLE | POWERCFG_RDSM;
	retval = si470x_set_register(radio, POWERCFG);
	if (retval < 0)
		goto done;

	/* sysconfig 1 */
	radio->registers[SYSCONFIG1] =
		(de << 11) & SYSCONFIG1_DE;		/* DE*/
	retval = si470x_set_register(radio, SYSCONFIG1);
	if (retval < 0)
		goto done;

	/* sysconfig 2 */
	radio->registers[SYSCONFIG2] =
		(0x1f  << 8) |				/* SEEKTH */
		((radio->band << 6) & SYSCONFIG2_BAND) |/* BAND */
		((space << 4) & SYSCONFIG2_SPACE) |	/* SPACE */
		15;					/* VOLUME (max) */
	retval = si470x_set_register(radio, SYSCONFIG2);
	if (retval < 0)
		goto done;

	/* reset last channel */
	retval = si470x_set_chan(radio,
		radio->registers[CHANNEL] & CHANNEL_CHAN);

done:
	return retval;
}


/*
 * si470x_stop - switch off radio
 */
int si470x_stop(struct si470x_device *radio)
{
	int retval;

	/* sysconfig 1 */
	radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
	retval = si470x_set_register(radio, SYSCONFIG1);
	if (retval < 0)
		goto done;

	/* powercfg */
	radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
	/* POWERCFG_ENABLE has to automatically go low */
	radio->registers[POWERCFG] |= POWERCFG_ENABLE |	POWERCFG_DISABLE;
	retval = si470x_set_register(radio, POWERCFG);

done:
	return retval;
}


/*
 * si470x_rds_on - switch on rds reception
 */
static int si470x_rds_on(struct si470x_device *radio)
{
	int retval;

	/* sysconfig 1 */
	radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDS;
	retval = si470x_set_register(radio, SYSCONFIG1);
	if (retval < 0)
		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;

	return retval;
}



/**************************************************************************
 * File Operations Interface
 **************************************************************************/

/*
 * si470x_fops_read - read RDS data
 */
static ssize_t si470x_fops_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct si470x_device *radio = video_drvdata(file);
	int retval = 0;
	unsigned int block_count = 0;

	/* switch on rds reception */
	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
		si470x_rds_on(radio);

	/* block if no new data available */
	while (radio->wr_index == radio->rd_index) {
		if (file->f_flags & O_NONBLOCK) {
			retval = -EWOULDBLOCK;
			goto done;
		}
		if (wait_event_interruptible(radio->read_queue,
			radio->wr_index != radio->rd_index) < 0) {
			retval = -EINTR;
			goto done;
		}
	}

	/* calculate block count from byte count */
	count /= 3;

	/* copy RDS block out of internal buffer and to user buffer */
	while (block_count < count) {
		if (radio->rd_index == radio->wr_index)
			break;

		/* always transfer rds complete blocks */
		if (copy_to_user(buf, &radio->buffer[radio->rd_index], 3))
			/* retval = -EFAULT; */
			break;

		/* increment and wrap read pointer */
		radio->rd_index += 3;
		if (radio->rd_index >= radio->buf_size)
			radio->rd_index = 0;

		/* increment counters */
		block_count++;
		buf += 3;
		retval += 3;
	}

done:
	return retval;
}


/*
 * si470x_fops_poll - poll RDS data
 */
static unsigned int si470x_fops_poll(struct file *file,
		struct poll_table_struct *pts)
{
	struct si470x_device *radio = video_drvdata(file);
	unsigned long req_events = poll_requested_events(pts);
	int retval = v4l2_ctrl_poll(file, pts);

	if (req_events & (POLLIN | POLLRDNORM)) {
		/* switch on rds reception */
		if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
			si470x_rds_on(radio);

		poll_wait(file, &radio->read_queue, pts);

		if (radio->rd_index != radio->wr_index)
			retval |= POLLIN | POLLRDNORM;
	}

	return retval;
}


/*
 * si470x_fops - file operations interface
 */
static const struct v4l2_file_operations si470x_fops = {
	.owner			= THIS_MODULE,
	.read			= si470x_fops_read,
	.poll			= si470x_fops_poll,
	.unlocked_ioctl		= video_ioctl2,
	.open			= si470x_fops_open,
	.release		= si470x_fops_release,
};



/**************************************************************************
 * Video4Linux Interface
 **************************************************************************/


static int si470x_s_ctrl(struct v4l2_ctrl *ctrl)
{
	struct si470x_device *radio =
		container_of(ctrl->handler, struct si470x_device, hdl);

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_VOLUME:
		radio->registers[SYSCONFIG2] &= ~SYSCONFIG2_VOLUME;
		radio->registers[SYSCONFIG2] |= ctrl->val;
		return si470x_set_register(radio, SYSCONFIG2);
	case V4L2_CID_AUDIO_MUTE:
		if (ctrl->val)
			radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
		else
			radio->registers[POWERCFG] |= POWERCFG_DMUTE;
		return si470x_set_register(radio, POWERCFG);
	default:
		return -EINVAL;
	}
}


/*
 * si470x_vidioc_g_tuner - get tuner attributes
 */
static int si470x_vidioc_g_tuner(struct file *file, void *priv,
		struct v4l2_tuner *tuner)
{
	struct si470x_device *radio = video_drvdata(file);
	int retval = 0;

	if (tuner->index != 0)
		return -EINVAL;

	if (!radio->status_rssi_auto_update) {
		retval = si470x_get_register(radio, STATUSRSSI);
		if (retval < 0)
			return retval;
	}

	/* driver constants */
	strcpy(tuner->name, "FM");
	tuner->type = V4L2_TUNER_RADIO;
	tuner->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
			    V4L2_TUNER_CAP_HWSEEK_WRAP;
	tuner->rangelow  =  76 * FREQ_MUL;
	tuner->rangehigh = 108 * FREQ_MUL;

	/* stereo indicator == stereo (instead of mono) */
	if ((radio->registers[STATUSRSSI] & STATUSRSSI_ST) == 0)
		tuner->rxsubchans = V4L2_TUNER_SUB_MONO;
	else
		tuner->rxsubchans = V4L2_TUNER_SUB_STEREO;
	/* If there is a reliable method of detecting an RDS channel,
	   then this code should check for that before setting this
	   RDS subchannel. */
	tuner->rxsubchans |= V4L2_TUNER_SUB_RDS;

	/* mono/stereo selector */
	if ((radio->registers[POWERCFG] & POWERCFG_MONO) == 0)
		tuner->audmode = V4L2_TUNER_MODE_STEREO;
	else
		tuner->audmode = V4L2_TUNER_MODE_MONO;

	/* min is worst, max is best; signal:0..0xffff; rssi: 0..0xff */
	/* measured in units of dbµV in 1 db increments (max at ~75 dbµV) */
	tuner->signal = (radio->registers[STATUSRSSI] & STATUSRSSI_RSSI);
	/* the ideal factor is 0xffff/75 = 873,8 */
	tuner->signal = (tuner->signal * 873) + (8 * tuner->signal / 10);
	if (tuner->signal > 0xffff)
		tuner->signal = 0xffff;

	/* automatic frequency control: -1: freq to low, 1 freq to high */
	/* AFCRL does only indicate that freq. differs, not if too low/high */
	tuner->afc = (radio->registers[STATUSRSSI] & STATUSRSSI_AFCRL) ? 1 : 0;

	return retval;
}


/*
 * si470x_vidioc_s_tuner - set tuner attributes
 */
static int si470x_vidioc_s_tuner(struct file *file, void *priv,
		const struct v4l2_tuner *tuner)
{
	struct si470x_device *radio = video_drvdata(file);

	if (tuner->index != 0)
		return -EINVAL;

	/* mono/stereo selector */
	switch (tuner->audmode) {
	case V4L2_TUNER_MODE_MONO:
		radio->registers[POWERCFG] |= POWERCFG_MONO;  /* force mono */
		break;
	case V4L2_TUNER_MODE_STEREO:
	default:
		radio->registers[POWERCFG] &= ~POWERCFG_MONO; /* try stereo */
		break;
	}

	return si470x_set_register(radio, POWERCFG);
}


/*
 * si470x_vidioc_g_frequency - get tuner or modulator radio frequency
 */
static int si470x_vidioc_g_frequency(struct file *file, void *priv,
		struct v4l2_frequency *freq)
{
	struct si470x_device *radio = video_drvdata(file);

	if (freq->tuner != 0)
		return -EINVAL;

	freq->type = V4L2_TUNER_RADIO;
	return si470x_get_freq(radio, &freq->frequency);
}


/*
 * si470x_vidioc_s_frequency - set tuner or modulator radio frequency
 */
static int si470x_vidioc_s_frequency(struct file *file, void *priv,
		const struct v4l2_frequency *freq)
{
	struct si470x_device *radio = video_drvdata(file);
	int retval;

	if (freq->tuner != 0)
		return -EINVAL;

	if (freq->frequency < bands[radio->band].rangelow ||
	    freq->frequency > bands[radio->band].rangehigh) {
		/* Switch to band 1 which covers everything we support */
		retval = si470x_set_band(radio, 1);
		if (retval)
			return retval;
	}
	return si470x_set_freq(radio, freq->frequency);
}


/*
 * si470x_vidioc_s_hw_freq_seek - set hardware frequency seek
 */
static int si470x_vidioc_s_hw_freq_seek(struct file *file, void *priv,
		const struct v4l2_hw_freq_seek *seek)
{
	struct si470x_device *radio = video_drvdata(file);

	if (seek->tuner != 0)
		return -EINVAL;

	if (file->f_flags & O_NONBLOCK)
		return -EWOULDBLOCK;

	return si470x_set_seek(radio, seek);
}

/*
 * si470x_vidioc_enum_freq_bands - enumerate supported bands
 */
static int si470x_vidioc_enum_freq_bands(struct file *file, void *priv,
					 struct v4l2_frequency_band *band)
{
	if (band->tuner != 0)
		return -EINVAL;
	if (band->index >= ARRAY_SIZE(bands))
		return -EINVAL;
	*band = bands[band->index];
	return 0;
}

const struct v4l2_ctrl_ops si470x_ctrl_ops = {
	.s_ctrl = si470x_s_ctrl,
};

/*
 * si470x_ioctl_ops - video device ioctl operations
 */
static const struct v4l2_ioctl_ops si470x_ioctl_ops = {
	.vidioc_querycap	= si470x_vidioc_querycap,
	.vidioc_g_tuner		= si470x_vidioc_g_tuner,
	.vidioc_s_tuner		= si470x_vidioc_s_tuner,
	.vidioc_g_frequency	= si470x_vidioc_g_frequency,
	.vidioc_s_frequency	= si470x_vidioc_s_frequency,
	.vidioc_s_hw_freq_seek	= si470x_vidioc_s_hw_freq_seek,
	.vidioc_enum_freq_bands = si470x_vidioc_enum_freq_bands,
	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
};


/*
 * si470x_viddev_template - video device interface
 */
struct video_device si470x_viddev_template = {
	.fops			= &si470x_fops,
	.name			= DRIVER_NAME,
	.release		= video_device_release_empty,
	.ioctl_ops		= &si470x_ioctl_ops,
};