xref: /linux/drivers/media/radio/si470x/radio-si470x-common.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  *  drivers/media/radio/si470x/radio-si470x-common.c
3  *
4  *  Driver for radios with Silicon Labs Si470x FM Radio Receivers
5  *
6  *  Copyright (c) 2009 Tobias Lorenz <tobias.lorenz@gmx.net>
7  *  Copyright (c) 2012 Hans de Goede <hdegoede@redhat.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 /*
26  * History:
27  * 2008-01-12	Tobias Lorenz <tobias.lorenz@gmx.net>
28  *		Version 1.0.0
29  *		- First working version
30  * 2008-01-13	Tobias Lorenz <tobias.lorenz@gmx.net>
31  *		Version 1.0.1
32  *		- Improved error handling, every function now returns errno
33  *		- Improved multi user access (start/mute/stop)
34  *		- Channel doesn't get lost anymore after start/mute/stop
35  *		- RDS support added (polling mode via interrupt EP 1)
36  *		- marked default module parameters with *value*
37  *		- switched from bit structs to bit masks
38  *		- header file cleaned and integrated
39  * 2008-01-14	Tobias Lorenz <tobias.lorenz@gmx.net>
40  * 		Version 1.0.2
41  * 		- hex values are now lower case
42  * 		- commented USB ID for ADS/Tech moved on todo list
43  * 		- blacklisted si470x in hid-quirks.c
44  * 		- rds buffer handling functions integrated into *_work, *_read
45  * 		- rds_command in si470x_poll exchanged against simple retval
46  * 		- check for firmware version 15
47  * 		- code order and prototypes still remain the same
48  * 		- spacing and bottom of band codes remain the same
49  * 2008-01-16	Tobias Lorenz <tobias.lorenz@gmx.net>
50  *		Version 1.0.3
51  * 		- code reordered to avoid function prototypes
52  *		- switch/case defaults are now more user-friendly
53  *		- unified comment style
54  *		- applied all checkpatch.pl v1.12 suggestions
55  *		  except the warning about the too long lines with bit comments
56  *		- renamed FMRADIO to RADIO to cut line length (checkpatch.pl)
57  * 2008-01-22	Tobias Lorenz <tobias.lorenz@gmx.net>
58  *		Version 1.0.4
59  *		- avoid poss. locking when doing copy_to_user which may sleep
60  *		- RDS is automatically activated on read now
61  *		- code cleaned of unnecessary rds_commands
62  *		- USB Vendor/Product ID for ADS/Tech FM Radio Receiver verified
63  *		  (thanks to Guillaume RAMOUSSE)
64  * 2008-01-27	Tobias Lorenz <tobias.lorenz@gmx.net>
65  *		Version 1.0.5
66  *		- number of seek_retries changed to tune_timeout
67  *		- fixed problem with incomplete tune operations by own buffers
68  *		- optimization of variables and printf types
69  *		- improved error logging
70  * 2008-01-31	Tobias Lorenz <tobias.lorenz@gmx.net>
71  *		Oliver Neukum <oliver@neukum.org>
72  *		Version 1.0.6
73  *		- fixed coverity checker warnings in *_usb_driver_disconnect
74  *		- probe()/open() race by correct ordering in probe()
75  *		- DMA coherency rules by separate allocation of all buffers
76  *		- use of endianness macros
77  *		- abuse of spinlock, replaced by mutex
78  *		- racy handling of timer in disconnect,
79  *		  replaced by delayed_work
80  *		- racy interruptible_sleep_on(),
81  *		  replaced with wait_event_interruptible()
82  *		- handle signals in read()
83  * 2008-02-08	Tobias Lorenz <tobias.lorenz@gmx.net>
84  *		Oliver Neukum <oliver@neukum.org>
85  *		Version 1.0.7
86  *		- usb autosuspend support
87  *		- unplugging fixed
88  * 2008-05-07	Tobias Lorenz <tobias.lorenz@gmx.net>
89  *		Version 1.0.8
90  *		- hardware frequency seek support
91  *		- afc indication
92  *		- more safety checks, let si470x_get_freq return errno
93  *		- vidioc behavior corrected according to v4l2 spec
94  * 2008-10-20	Alexey Klimov <klimov.linux@gmail.com>
95  * 		- add support for KWorld USB FM Radio FM700
96  * 		- blacklisted KWorld radio in hid-core.c and hid-ids.h
97  * 2008-12-03	Mark Lord <mlord@pobox.com>
98  *		- add support for DealExtreme USB Radio
99  * 2009-01-31	Bob Ross <pigiron@gmx.com>
100  *		- correction of stereo detection/setting
101  *		- correction of signal strength indicator scaling
102  * 2009-01-31	Rick Bronson <rick@efn.org>
103  *		Tobias Lorenz <tobias.lorenz@gmx.net>
104  *		- add LED status output
105  *		- get HW/SW version from scratchpad
106  * 2009-06-16   Edouard Lafargue <edouard@lafargue.name>
107  *		Version 1.0.10
108  *		- add support for interrupt mode for RDS endpoint,
109  *                instead of polling.
110  *                Improves RDS reception significantly
111  */
112 
113 
114 /* kernel includes */
115 #include "radio-si470x.h"
116 
117 
118 
119 /**************************************************************************
120  * Module Parameters
121  **************************************************************************/
122 
123 /* Spacing (kHz) */
124 /* 0: 200 kHz (USA, Australia) */
125 /* 1: 100 kHz (Europe, Japan) */
126 /* 2:  50 kHz */
127 static unsigned short space = 2;
128 module_param(space, ushort, 0444);
129 MODULE_PARM_DESC(space, "Spacing: 0=200kHz 1=100kHz *2=50kHz*");
130 
131 /* De-emphasis */
132 /* 0: 75 us (USA) */
133 /* 1: 50 us (Europe, Australia, Japan) */
134 static unsigned short de = 1;
135 module_param(de, ushort, 0444);
136 MODULE_PARM_DESC(de, "De-emphasis: 0=75us *1=50us*");
137 
138 /* Tune timeout */
139 static unsigned int tune_timeout = 3000;
140 module_param(tune_timeout, uint, 0644);
141 MODULE_PARM_DESC(tune_timeout, "Tune timeout: *3000*");
142 
143 /* Seek timeout */
144 static unsigned int seek_timeout = 5000;
145 module_param(seek_timeout, uint, 0644);
146 MODULE_PARM_DESC(seek_timeout, "Seek timeout: *5000*");
147 
148 static const struct v4l2_frequency_band bands[] = {
149 	{
150 		.type = V4L2_TUNER_RADIO,
151 		.index = 0,
152 		.capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
153 			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
154 			    V4L2_TUNER_CAP_FREQ_BANDS |
155 			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
156 			    V4L2_TUNER_CAP_HWSEEK_WRAP,
157 		.rangelow   =  87500 * 16,
158 		.rangehigh  = 108000 * 16,
159 		.modulation = V4L2_BAND_MODULATION_FM,
160 	},
161 	{
162 		.type = V4L2_TUNER_RADIO,
163 		.index = 1,
164 		.capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
165 			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
166 			    V4L2_TUNER_CAP_FREQ_BANDS |
167 			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
168 			    V4L2_TUNER_CAP_HWSEEK_WRAP,
169 		.rangelow   =  76000 * 16,
170 		.rangehigh  = 108000 * 16,
171 		.modulation = V4L2_BAND_MODULATION_FM,
172 	},
173 	{
174 		.type = V4L2_TUNER_RADIO,
175 		.index = 2,
176 		.capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
177 			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
178 			    V4L2_TUNER_CAP_FREQ_BANDS |
179 			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
180 			    V4L2_TUNER_CAP_HWSEEK_WRAP,
181 		.rangelow   =  76000 * 16,
182 		.rangehigh  =  90000 * 16,
183 		.modulation = V4L2_BAND_MODULATION_FM,
184 	},
185 };
186 
187 /**************************************************************************
188  * Generic Functions
189  **************************************************************************/
190 
191 /*
192  * si470x_set_band - set the band
193  */
194 static int si470x_set_band(struct si470x_device *radio, int band)
195 {
196 	if (radio->band == band)
197 		return 0;
198 
199 	radio->band = band;
200 	radio->registers[SYSCONFIG2] &= ~SYSCONFIG2_BAND;
201 	radio->registers[SYSCONFIG2] |= radio->band << 6;
202 	return si470x_set_register(radio, SYSCONFIG2);
203 }
204 
205 /*
206  * si470x_set_chan - set the channel
207  */
208 static int si470x_set_chan(struct si470x_device *radio, unsigned short chan)
209 {
210 	int retval;
211 	unsigned long time_left;
212 	bool timed_out = false;
213 
214 	/* start tuning */
215 	radio->registers[CHANNEL] &= ~CHANNEL_CHAN;
216 	radio->registers[CHANNEL] |= CHANNEL_TUNE | chan;
217 	retval = si470x_set_register(radio, CHANNEL);
218 	if (retval < 0)
219 		goto done;
220 
221 	/* wait till tune operation has completed */
222 	reinit_completion(&radio->completion);
223 	time_left = wait_for_completion_timeout(&radio->completion,
224 						msecs_to_jiffies(tune_timeout));
225 	if (time_left == 0)
226 		timed_out = true;
227 
228 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
229 		dev_warn(&radio->videodev.dev, "tune does not complete\n");
230 	if (timed_out)
231 		dev_warn(&radio->videodev.dev,
232 			"tune timed out after %u ms\n", tune_timeout);
233 
234 	/* stop tuning */
235 	radio->registers[CHANNEL] &= ~CHANNEL_TUNE;
236 	retval = si470x_set_register(radio, CHANNEL);
237 
238 done:
239 	return retval;
240 }
241 
242 /*
243  * si470x_get_step - get channel spacing
244  */
245 static unsigned int si470x_get_step(struct si470x_device *radio)
246 {
247 	/* Spacing (kHz) */
248 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_SPACE) >> 4) {
249 	/* 0: 200 kHz (USA, Australia) */
250 	case 0:
251 		return 200 * 16;
252 	/* 1: 100 kHz (Europe, Japan) */
253 	case 1:
254 		return 100 * 16;
255 	/* 2:  50 kHz */
256 	default:
257 		return 50 * 16;
258 	}
259 }
260 
261 
262 /*
263  * si470x_get_freq - get the frequency
264  */
265 static int si470x_get_freq(struct si470x_device *radio, unsigned int *freq)
266 {
267 	int chan, retval;
268 
269 	/* read channel */
270 	retval = si470x_get_register(radio, READCHAN);
271 	chan = radio->registers[READCHAN] & READCHAN_READCHAN;
272 
273 	/* Frequency (MHz) = Spacing (kHz) x Channel + Bottom of Band (MHz) */
274 	*freq = chan * si470x_get_step(radio) + bands[radio->band].rangelow;
275 
276 	return retval;
277 }
278 
279 
280 /*
281  * si470x_set_freq - set the frequency
282  */
283 int si470x_set_freq(struct si470x_device *radio, unsigned int freq)
284 {
285 	unsigned short chan;
286 
287 	freq = clamp(freq, bands[radio->band].rangelow,
288 			   bands[radio->band].rangehigh);
289 	/* Chan = [ Freq (Mhz) - Bottom of Band (MHz) ] / Spacing (kHz) */
290 	chan = (freq - bands[radio->band].rangelow) / si470x_get_step(radio);
291 
292 	return si470x_set_chan(radio, chan);
293 }
294 
295 
296 /*
297  * si470x_set_seek - set seek
298  */
299 static int si470x_set_seek(struct si470x_device *radio,
300 			   const struct v4l2_hw_freq_seek *seek)
301 {
302 	int band, retval;
303 	unsigned int freq;
304 	bool timed_out = false;
305 	unsigned long time_left;
306 
307 	/* set band */
308 	if (seek->rangelow || seek->rangehigh) {
309 		for (band = 0; band < ARRAY_SIZE(bands); band++) {
310 			if (bands[band].rangelow  == seek->rangelow &&
311 			    bands[band].rangehigh == seek->rangehigh)
312 				break;
313 		}
314 		if (band == ARRAY_SIZE(bands))
315 			return -EINVAL; /* No matching band found */
316 	} else
317 		band = 1; /* If nothing is specified seek 76 - 108 Mhz */
318 
319 	if (radio->band != band) {
320 		retval = si470x_get_freq(radio, &freq);
321 		if (retval)
322 			return retval;
323 		retval = si470x_set_band(radio, band);
324 		if (retval)
325 			return retval;
326 		retval = si470x_set_freq(radio, freq);
327 		if (retval)
328 			return retval;
329 	}
330 
331 	/* start seeking */
332 	radio->registers[POWERCFG] |= POWERCFG_SEEK;
333 	if (seek->wrap_around)
334 		radio->registers[POWERCFG] &= ~POWERCFG_SKMODE;
335 	else
336 		radio->registers[POWERCFG] |= POWERCFG_SKMODE;
337 	if (seek->seek_upward)
338 		radio->registers[POWERCFG] |= POWERCFG_SEEKUP;
339 	else
340 		radio->registers[POWERCFG] &= ~POWERCFG_SEEKUP;
341 	retval = si470x_set_register(radio, POWERCFG);
342 	if (retval < 0)
343 		return retval;
344 
345 	/* wait till tune operation has completed */
346 	reinit_completion(&radio->completion);
347 	time_left = wait_for_completion_timeout(&radio->completion,
348 						msecs_to_jiffies(seek_timeout));
349 	if (time_left == 0)
350 		timed_out = true;
351 
352 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
353 		dev_warn(&radio->videodev.dev, "seek does not complete\n");
354 	if (radio->registers[STATUSRSSI] & STATUSRSSI_SF)
355 		dev_warn(&radio->videodev.dev,
356 			"seek failed / band limit reached\n");
357 
358 	/* stop seeking */
359 	radio->registers[POWERCFG] &= ~POWERCFG_SEEK;
360 	retval = si470x_set_register(radio, POWERCFG);
361 
362 	/* try again, if timed out */
363 	if (retval == 0 && timed_out)
364 		return -ENODATA;
365 	return retval;
366 }
367 
368 
369 /*
370  * si470x_start - switch on radio
371  */
372 int si470x_start(struct si470x_device *radio)
373 {
374 	int retval;
375 
376 	/* powercfg */
377 	radio->registers[POWERCFG] =
378 		POWERCFG_DMUTE | POWERCFG_ENABLE | POWERCFG_RDSM;
379 	retval = si470x_set_register(radio, POWERCFG);
380 	if (retval < 0)
381 		goto done;
382 
383 	/* sysconfig 1 */
384 	radio->registers[SYSCONFIG1] =
385 		(de << 11) & SYSCONFIG1_DE;		/* DE*/
386 	retval = si470x_set_register(radio, SYSCONFIG1);
387 	if (retval < 0)
388 		goto done;
389 
390 	/* sysconfig 2 */
391 	radio->registers[SYSCONFIG2] =
392 		(0x1f  << 8) |				/* SEEKTH */
393 		((radio->band << 6) & SYSCONFIG2_BAND) |/* BAND */
394 		((space << 4) & SYSCONFIG2_SPACE) |	/* SPACE */
395 		15;					/* VOLUME (max) */
396 	retval = si470x_set_register(radio, SYSCONFIG2);
397 	if (retval < 0)
398 		goto done;
399 
400 	/* reset last channel */
401 	retval = si470x_set_chan(radio,
402 		radio->registers[CHANNEL] & CHANNEL_CHAN);
403 
404 done:
405 	return retval;
406 }
407 
408 
409 /*
410  * si470x_stop - switch off radio
411  */
412 int si470x_stop(struct si470x_device *radio)
413 {
414 	int retval;
415 
416 	/* sysconfig 1 */
417 	radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
418 	retval = si470x_set_register(radio, SYSCONFIG1);
419 	if (retval < 0)
420 		goto done;
421 
422 	/* powercfg */
423 	radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
424 	/* POWERCFG_ENABLE has to automatically go low */
425 	radio->registers[POWERCFG] |= POWERCFG_ENABLE |	POWERCFG_DISABLE;
426 	retval = si470x_set_register(radio, POWERCFG);
427 
428 done:
429 	return retval;
430 }
431 
432 
433 /*
434  * si470x_rds_on - switch on rds reception
435  */
436 static int si470x_rds_on(struct si470x_device *radio)
437 {
438 	int retval;
439 
440 	/* sysconfig 1 */
441 	radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDS;
442 	retval = si470x_set_register(radio, SYSCONFIG1);
443 	if (retval < 0)
444 		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
445 
446 	return retval;
447 }
448 
449 
450 
451 /**************************************************************************
452  * File Operations Interface
453  **************************************************************************/
454 
455 /*
456  * si470x_fops_read - read RDS data
457  */
458 static ssize_t si470x_fops_read(struct file *file, char __user *buf,
459 		size_t count, loff_t *ppos)
460 {
461 	struct si470x_device *radio = video_drvdata(file);
462 	int retval = 0;
463 	unsigned int block_count = 0;
464 
465 	/* switch on rds reception */
466 	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
467 		si470x_rds_on(radio);
468 
469 	/* block if no new data available */
470 	while (radio->wr_index == radio->rd_index) {
471 		if (file->f_flags & O_NONBLOCK) {
472 			retval = -EWOULDBLOCK;
473 			goto done;
474 		}
475 		if (wait_event_interruptible(radio->read_queue,
476 			radio->wr_index != radio->rd_index) < 0) {
477 			retval = -EINTR;
478 			goto done;
479 		}
480 	}
481 
482 	/* calculate block count from byte count */
483 	count /= 3;
484 
485 	/* copy RDS block out of internal buffer and to user buffer */
486 	while (block_count < count) {
487 		if (radio->rd_index == radio->wr_index)
488 			break;
489 
490 		/* always transfer rds complete blocks */
491 		if (copy_to_user(buf, &radio->buffer[radio->rd_index], 3))
492 			/* retval = -EFAULT; */
493 			break;
494 
495 		/* increment and wrap read pointer */
496 		radio->rd_index += 3;
497 		if (radio->rd_index >= radio->buf_size)
498 			radio->rd_index = 0;
499 
500 		/* increment counters */
501 		block_count++;
502 		buf += 3;
503 		retval += 3;
504 	}
505 
506 done:
507 	return retval;
508 }
509 
510 
511 /*
512  * si470x_fops_poll - poll RDS data
513  */
514 static unsigned int si470x_fops_poll(struct file *file,
515 		struct poll_table_struct *pts)
516 {
517 	struct si470x_device *radio = video_drvdata(file);
518 	unsigned long req_events = poll_requested_events(pts);
519 	int retval = v4l2_ctrl_poll(file, pts);
520 
521 	if (req_events & (POLLIN | POLLRDNORM)) {
522 		/* switch on rds reception */
523 		if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
524 			si470x_rds_on(radio);
525 
526 		poll_wait(file, &radio->read_queue, pts);
527 
528 		if (radio->rd_index != radio->wr_index)
529 			retval |= POLLIN | POLLRDNORM;
530 	}
531 
532 	return retval;
533 }
534 
535 
536 /*
537  * si470x_fops - file operations interface
538  */
539 static const struct v4l2_file_operations si470x_fops = {
540 	.owner			= THIS_MODULE,
541 	.read			= si470x_fops_read,
542 	.poll			= si470x_fops_poll,
543 	.unlocked_ioctl		= video_ioctl2,
544 	.open			= si470x_fops_open,
545 	.release		= si470x_fops_release,
546 };
547 
548 
549 
550 /**************************************************************************
551  * Video4Linux Interface
552  **************************************************************************/
553 
554 
555 static int si470x_s_ctrl(struct v4l2_ctrl *ctrl)
556 {
557 	struct si470x_device *radio =
558 		container_of(ctrl->handler, struct si470x_device, hdl);
559 
560 	switch (ctrl->id) {
561 	case V4L2_CID_AUDIO_VOLUME:
562 		radio->registers[SYSCONFIG2] &= ~SYSCONFIG2_VOLUME;
563 		radio->registers[SYSCONFIG2] |= ctrl->val;
564 		return si470x_set_register(radio, SYSCONFIG2);
565 	case V4L2_CID_AUDIO_MUTE:
566 		if (ctrl->val)
567 			radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
568 		else
569 			radio->registers[POWERCFG] |= POWERCFG_DMUTE;
570 		return si470x_set_register(radio, POWERCFG);
571 	default:
572 		return -EINVAL;
573 	}
574 }
575 
576 
577 /*
578  * si470x_vidioc_g_tuner - get tuner attributes
579  */
580 static int si470x_vidioc_g_tuner(struct file *file, void *priv,
581 		struct v4l2_tuner *tuner)
582 {
583 	struct si470x_device *radio = video_drvdata(file);
584 	int retval = 0;
585 
586 	if (tuner->index != 0)
587 		return -EINVAL;
588 
589 	if (!radio->status_rssi_auto_update) {
590 		retval = si470x_get_register(radio, STATUSRSSI);
591 		if (retval < 0)
592 			return retval;
593 	}
594 
595 	/* driver constants */
596 	strcpy(tuner->name, "FM");
597 	tuner->type = V4L2_TUNER_RADIO;
598 	tuner->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
599 			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
600 			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
601 			    V4L2_TUNER_CAP_HWSEEK_WRAP;
602 	tuner->rangelow  =  76 * FREQ_MUL;
603 	tuner->rangehigh = 108 * FREQ_MUL;
604 
605 	/* stereo indicator == stereo (instead of mono) */
606 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_ST) == 0)
607 		tuner->rxsubchans = V4L2_TUNER_SUB_MONO;
608 	else
609 		tuner->rxsubchans = V4L2_TUNER_SUB_STEREO;
610 	/* If there is a reliable method of detecting an RDS channel,
611 	   then this code should check for that before setting this
612 	   RDS subchannel. */
613 	tuner->rxsubchans |= V4L2_TUNER_SUB_RDS;
614 
615 	/* mono/stereo selector */
616 	if ((radio->registers[POWERCFG] & POWERCFG_MONO) == 0)
617 		tuner->audmode = V4L2_TUNER_MODE_STEREO;
618 	else
619 		tuner->audmode = V4L2_TUNER_MODE_MONO;
620 
621 	/* min is worst, max is best; signal:0..0xffff; rssi: 0..0xff */
622 	/* measured in units of dbµV in 1 db increments (max at ~75 dbµV) */
623 	tuner->signal = (radio->registers[STATUSRSSI] & STATUSRSSI_RSSI);
624 	/* the ideal factor is 0xffff/75 = 873,8 */
625 	tuner->signal = (tuner->signal * 873) + (8 * tuner->signal / 10);
626 	if (tuner->signal > 0xffff)
627 		tuner->signal = 0xffff;
628 
629 	/* automatic frequency control: -1: freq to low, 1 freq to high */
630 	/* AFCRL does only indicate that freq. differs, not if too low/high */
631 	tuner->afc = (radio->registers[STATUSRSSI] & STATUSRSSI_AFCRL) ? 1 : 0;
632 
633 	return retval;
634 }
635 
636 
637 /*
638  * si470x_vidioc_s_tuner - set tuner attributes
639  */
640 static int si470x_vidioc_s_tuner(struct file *file, void *priv,
641 		const struct v4l2_tuner *tuner)
642 {
643 	struct si470x_device *radio = video_drvdata(file);
644 
645 	if (tuner->index != 0)
646 		return -EINVAL;
647 
648 	/* mono/stereo selector */
649 	switch (tuner->audmode) {
650 	case V4L2_TUNER_MODE_MONO:
651 		radio->registers[POWERCFG] |= POWERCFG_MONO;  /* force mono */
652 		break;
653 	case V4L2_TUNER_MODE_STEREO:
654 	default:
655 		radio->registers[POWERCFG] &= ~POWERCFG_MONO; /* try stereo */
656 		break;
657 	}
658 
659 	return si470x_set_register(radio, POWERCFG);
660 }
661 
662 
663 /*
664  * si470x_vidioc_g_frequency - get tuner or modulator radio frequency
665  */
666 static int si470x_vidioc_g_frequency(struct file *file, void *priv,
667 		struct v4l2_frequency *freq)
668 {
669 	struct si470x_device *radio = video_drvdata(file);
670 
671 	if (freq->tuner != 0)
672 		return -EINVAL;
673 
674 	freq->type = V4L2_TUNER_RADIO;
675 	return si470x_get_freq(radio, &freq->frequency);
676 }
677 
678 
679 /*
680  * si470x_vidioc_s_frequency - set tuner or modulator radio frequency
681  */
682 static int si470x_vidioc_s_frequency(struct file *file, void *priv,
683 		const struct v4l2_frequency *freq)
684 {
685 	struct si470x_device *radio = video_drvdata(file);
686 	int retval;
687 
688 	if (freq->tuner != 0)
689 		return -EINVAL;
690 
691 	if (freq->frequency < bands[radio->band].rangelow ||
692 	    freq->frequency > bands[radio->band].rangehigh) {
693 		/* Switch to band 1 which covers everything we support */
694 		retval = si470x_set_band(radio, 1);
695 		if (retval)
696 			return retval;
697 	}
698 	return si470x_set_freq(radio, freq->frequency);
699 }
700 
701 
702 /*
703  * si470x_vidioc_s_hw_freq_seek - set hardware frequency seek
704  */
705 static int si470x_vidioc_s_hw_freq_seek(struct file *file, void *priv,
706 		const struct v4l2_hw_freq_seek *seek)
707 {
708 	struct si470x_device *radio = video_drvdata(file);
709 
710 	if (seek->tuner != 0)
711 		return -EINVAL;
712 
713 	if (file->f_flags & O_NONBLOCK)
714 		return -EWOULDBLOCK;
715 
716 	return si470x_set_seek(radio, seek);
717 }
718 
719 /*
720  * si470x_vidioc_enum_freq_bands - enumerate supported bands
721  */
722 static int si470x_vidioc_enum_freq_bands(struct file *file, void *priv,
723 					 struct v4l2_frequency_band *band)
724 {
725 	if (band->tuner != 0)
726 		return -EINVAL;
727 	if (band->index >= ARRAY_SIZE(bands))
728 		return -EINVAL;
729 	*band = bands[band->index];
730 	return 0;
731 }
732 
733 const struct v4l2_ctrl_ops si470x_ctrl_ops = {
734 	.s_ctrl = si470x_s_ctrl,
735 };
736 
737 /*
738  * si470x_ioctl_ops - video device ioctl operations
739  */
740 static const struct v4l2_ioctl_ops si470x_ioctl_ops = {
741 	.vidioc_querycap	= si470x_vidioc_querycap,
742 	.vidioc_g_tuner		= si470x_vidioc_g_tuner,
743 	.vidioc_s_tuner		= si470x_vidioc_s_tuner,
744 	.vidioc_g_frequency	= si470x_vidioc_g_frequency,
745 	.vidioc_s_frequency	= si470x_vidioc_s_frequency,
746 	.vidioc_s_hw_freq_seek	= si470x_vidioc_s_hw_freq_seek,
747 	.vidioc_enum_freq_bands = si470x_vidioc_enum_freq_bands,
748 	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
749 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
750 };
751 
752 
753 /*
754  * si470x_viddev_template - video device interface
755  */
756 struct video_device si470x_viddev_template = {
757 	.fops			= &si470x_fops,
758 	.name			= DRIVER_NAME,
759 	.release		= video_device_release_empty,
760 	.ioctl_ops		= &si470x_ioctl_ops,
761 };
762