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  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21  */
22 
23 
24 /*
25  * History:
26  * 2008-01-12	Tobias Lorenz <tobias.lorenz@gmx.net>
27  *		Version 1.0.0
28  *		- First working version
29  * 2008-01-13	Tobias Lorenz <tobias.lorenz@gmx.net>
30  *		Version 1.0.1
31  *		- Improved error handling, every function now returns errno
32  *		- Improved multi user access (start/mute/stop)
33  *		- Channel doesn't get lost anymore after start/mute/stop
34  *		- RDS support added (polling mode via interrupt EP 1)
35  *		- marked default module parameters with *value*
36  *		- switched from bit structs to bit masks
37  *		- header file cleaned and integrated
38  * 2008-01-14	Tobias Lorenz <tobias.lorenz@gmx.net>
39  * 		Version 1.0.2
40  * 		- hex values are now lower case
41  * 		- commented USB ID for ADS/Tech moved on todo list
42  * 		- blacklisted si470x in hid-quirks.c
43  * 		- rds buffer handling functions integrated into *_work, *_read
44  * 		- rds_command in si470x_poll exchanged against simple retval
45  * 		- check for firmware version 15
46  * 		- code order and prototypes still remain the same
47  * 		- spacing and bottom of band codes remain the same
48  * 2008-01-16	Tobias Lorenz <tobias.lorenz@gmx.net>
49  *		Version 1.0.3
50  * 		- code reordered to avoid function prototypes
51  *		- switch/case defaults are now more user-friendly
52  *		- unified comment style
53  *		- applied all checkpatch.pl v1.12 suggestions
54  *		  except the warning about the too long lines with bit comments
55  *		- renamed FMRADIO to RADIO to cut line length (checkpatch.pl)
56  * 2008-01-22	Tobias Lorenz <tobias.lorenz@gmx.net>
57  *		Version 1.0.4
58  *		- avoid poss. locking when doing copy_to_user which may sleep
59  *		- RDS is automatically activated on read now
60  *		- code cleaned of unnecessary rds_commands
61  *		- USB Vendor/Product ID for ADS/Tech FM Radio Receiver verified
62  *		  (thanks to Guillaume RAMOUSSE)
63  * 2008-01-27	Tobias Lorenz <tobias.lorenz@gmx.net>
64  *		Version 1.0.5
65  *		- number of seek_retries changed to tune_timeout
66  *		- fixed problem with incomplete tune operations by own buffers
67  *		- optimization of variables and printf types
68  *		- improved error logging
69  * 2008-01-31	Tobias Lorenz <tobias.lorenz@gmx.net>
70  *		Oliver Neukum <oliver@neukum.org>
71  *		Version 1.0.6
72  *		- fixed coverity checker warnings in *_usb_driver_disconnect
73  *		- probe()/open() race by correct ordering in probe()
74  *		- DMA coherency rules by separate allocation of all buffers
75  *		- use of endianness macros
76  *		- abuse of spinlock, replaced by mutex
77  *		- racy handling of timer in disconnect,
78  *		  replaced by delayed_work
79  *		- racy interruptible_sleep_on(),
80  *		  replaced with wait_event_interruptible()
81  *		- handle signals in read()
82  * 2008-02-08	Tobias Lorenz <tobias.lorenz@gmx.net>
83  *		Oliver Neukum <oliver@neukum.org>
84  *		Version 1.0.7
85  *		- usb autosuspend support
86  *		- unplugging fixed
87  * 2008-05-07	Tobias Lorenz <tobias.lorenz@gmx.net>
88  *		Version 1.0.8
89  *		- hardware frequency seek support
90  *		- afc indication
91  *		- more safety checks, let si470x_get_freq return errno
92  *		- vidioc behavior corrected according to v4l2 spec
93  * 2008-10-20	Alexey Klimov <klimov.linux@gmail.com>
94  * 		- add support for KWorld USB FM Radio FM700
95  * 		- blacklisted KWorld radio in hid-core.c and hid-ids.h
96  * 2008-12-03	Mark Lord <mlord@pobox.com>
97  *		- add support for DealExtreme USB Radio
98  * 2009-01-31	Bob Ross <pigiron@gmx.com>
99  *		- correction of stereo detection/setting
100  *		- correction of signal strength indicator scaling
101  * 2009-01-31	Rick Bronson <rick@efn.org>
102  *		Tobias Lorenz <tobias.lorenz@gmx.net>
103  *		- add LED status output
104  *		- get HW/SW version from scratchpad
105  * 2009-06-16   Edouard Lafargue <edouard@lafargue.name>
106  *		Version 1.0.10
107  *		- add support for interrupt mode for RDS endpoint,
108  *                instead of polling.
109  *                Improves RDS reception significantly
110  */
111 
112 
113 /* kernel includes */
114 #include "radio-si470x.h"
115 
116 
117 
118 /**************************************************************************
119  * Module Parameters
120  **************************************************************************/
121 
122 /* Spacing (kHz) */
123 /* 0: 200 kHz (USA, Australia) */
124 /* 1: 100 kHz (Europe, Japan) */
125 /* 2:  50 kHz */
126 static unsigned short space = 2;
127 module_param(space, ushort, 0444);
128 MODULE_PARM_DESC(space, "Spacing: 0=200kHz 1=100kHz *2=50kHz*");
129 
130 /* Bottom of Band (MHz) */
131 /* 0: 87.5 - 108 MHz (USA, Europe)*/
132 /* 1: 76   - 108 MHz (Japan wide band) */
133 /* 2: 76   -  90 MHz (Japan) */
134 static unsigned short band = 1;
135 module_param(band, ushort, 0444);
136 MODULE_PARM_DESC(band, "Band: 0=87.5..108MHz *1=76..108MHz* 2=76..90MHz");
137 
138 /* De-emphasis */
139 /* 0: 75 us (USA) */
140 /* 1: 50 us (Europe, Australia, Japan) */
141 static unsigned short de = 1;
142 module_param(de, ushort, 0444);
143 MODULE_PARM_DESC(de, "De-emphasis: 0=75us *1=50us*");
144 
145 /* Tune timeout */
146 static unsigned int tune_timeout = 3000;
147 module_param(tune_timeout, uint, 0644);
148 MODULE_PARM_DESC(tune_timeout, "Tune timeout: *3000*");
149 
150 /* Seek timeout */
151 static unsigned int seek_timeout = 5000;
152 module_param(seek_timeout, uint, 0644);
153 MODULE_PARM_DESC(seek_timeout, "Seek timeout: *5000*");
154 
155 
156 
157 /**************************************************************************
158  * Generic Functions
159  **************************************************************************/
160 
161 /*
162  * si470x_set_chan - set the channel
163  */
164 static int si470x_set_chan(struct si470x_device *radio, unsigned short chan)
165 {
166 	int retval;
167 	unsigned long timeout;
168 	bool timed_out = 0;
169 
170 	/* start tuning */
171 	radio->registers[CHANNEL] &= ~CHANNEL_CHAN;
172 	radio->registers[CHANNEL] |= CHANNEL_TUNE | chan;
173 	retval = si470x_set_register(radio, CHANNEL);
174 	if (retval < 0)
175 		goto done;
176 
177 	/* wait till tune operation has completed */
178 	timeout = jiffies + msecs_to_jiffies(tune_timeout);
179 	do {
180 		retval = si470x_get_register(radio, STATUSRSSI);
181 		if (retval < 0)
182 			goto stop;
183 		timed_out = time_after(jiffies, timeout);
184 	} while (((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0) &&
185 		(!timed_out));
186 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
187 		dev_warn(&radio->videodev->dev, "tune does not complete\n");
188 	if (timed_out)
189 		dev_warn(&radio->videodev->dev,
190 			"tune timed out after %u ms\n", tune_timeout);
191 
192 stop:
193 	/* stop tuning */
194 	radio->registers[CHANNEL] &= ~CHANNEL_TUNE;
195 	retval = si470x_set_register(radio, CHANNEL);
196 
197 done:
198 	return retval;
199 }
200 
201 
202 /*
203  * si470x_get_freq - get the frequency
204  */
205 static int si470x_get_freq(struct si470x_device *radio, unsigned int *freq)
206 {
207 	unsigned int spacing, band_bottom;
208 	unsigned short chan;
209 	int retval;
210 
211 	/* Spacing (kHz) */
212 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_SPACE) >> 4) {
213 	/* 0: 200 kHz (USA, Australia) */
214 	case 0:
215 		spacing = 0.200 * FREQ_MUL; break;
216 	/* 1: 100 kHz (Europe, Japan) */
217 	case 1:
218 		spacing = 0.100 * FREQ_MUL; break;
219 	/* 2:  50 kHz */
220 	default:
221 		spacing = 0.050 * FREQ_MUL; break;
222 	};
223 
224 	/* Bottom of Band (MHz) */
225 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_BAND) >> 6) {
226 	/* 0: 87.5 - 108 MHz (USA, Europe) */
227 	case 0:
228 		band_bottom = 87.5 * FREQ_MUL; break;
229 	/* 1: 76   - 108 MHz (Japan wide band) */
230 	default:
231 		band_bottom = 76   * FREQ_MUL; break;
232 	/* 2: 76   -  90 MHz (Japan) */
233 	case 2:
234 		band_bottom = 76   * FREQ_MUL; break;
235 	};
236 
237 	/* read channel */
238 	retval = si470x_get_register(radio, READCHAN);
239 	chan = radio->registers[READCHAN] & READCHAN_READCHAN;
240 
241 	/* Frequency (MHz) = Spacing (kHz) x Channel + Bottom of Band (MHz) */
242 	*freq = chan * spacing + band_bottom;
243 
244 	return retval;
245 }
246 
247 
248 /*
249  * si470x_set_freq - set the frequency
250  */
251 int si470x_set_freq(struct si470x_device *radio, unsigned int freq)
252 {
253 	unsigned int spacing, band_bottom;
254 	unsigned short chan;
255 
256 	/* Spacing (kHz) */
257 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_SPACE) >> 4) {
258 	/* 0: 200 kHz (USA, Australia) */
259 	case 0:
260 		spacing = 0.200 * FREQ_MUL; break;
261 	/* 1: 100 kHz (Europe, Japan) */
262 	case 1:
263 		spacing = 0.100 * FREQ_MUL; break;
264 	/* 2:  50 kHz */
265 	default:
266 		spacing = 0.050 * FREQ_MUL; break;
267 	};
268 
269 	/* Bottom of Band (MHz) */
270 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_BAND) >> 6) {
271 	/* 0: 87.5 - 108 MHz (USA, Europe) */
272 	case 0:
273 		band_bottom = 87.5 * FREQ_MUL; break;
274 	/* 1: 76   - 108 MHz (Japan wide band) */
275 	default:
276 		band_bottom = 76   * FREQ_MUL; break;
277 	/* 2: 76   -  90 MHz (Japan) */
278 	case 2:
279 		band_bottom = 76   * FREQ_MUL; break;
280 	};
281 
282 	/* Chan = [ Freq (Mhz) - Bottom of Band (MHz) ] / Spacing (kHz) */
283 	chan = (freq - band_bottom) / spacing;
284 
285 	return si470x_set_chan(radio, chan);
286 }
287 
288 
289 /*
290  * si470x_set_seek - set seek
291  */
292 static int si470x_set_seek(struct si470x_device *radio,
293 		unsigned int wrap_around, unsigned int seek_upward)
294 {
295 	int retval = 0;
296 	unsigned long timeout;
297 	bool timed_out = 0;
298 
299 	/* start seeking */
300 	radio->registers[POWERCFG] |= POWERCFG_SEEK;
301 	if (wrap_around == 1)
302 		radio->registers[POWERCFG] &= ~POWERCFG_SKMODE;
303 	else
304 		radio->registers[POWERCFG] |= POWERCFG_SKMODE;
305 	if (seek_upward == 1)
306 		radio->registers[POWERCFG] |= POWERCFG_SEEKUP;
307 	else
308 		radio->registers[POWERCFG] &= ~POWERCFG_SEEKUP;
309 	retval = si470x_set_register(radio, POWERCFG);
310 	if (retval < 0)
311 		goto done;
312 
313 	/* wait till seek operation has completed */
314 	timeout = jiffies + msecs_to_jiffies(seek_timeout);
315 	do {
316 		retval = si470x_get_register(radio, STATUSRSSI);
317 		if (retval < 0)
318 			goto stop;
319 		timed_out = time_after(jiffies, timeout);
320 	} while (((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0) &&
321 		(!timed_out));
322 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
323 		dev_warn(&radio->videodev->dev, "seek does not complete\n");
324 	if (radio->registers[STATUSRSSI] & STATUSRSSI_SF)
325 		dev_warn(&radio->videodev->dev,
326 			"seek failed / band limit reached\n");
327 	if (timed_out)
328 		dev_warn(&radio->videodev->dev,
329 			"seek timed out after %u ms\n", seek_timeout);
330 
331 stop:
332 	/* stop seeking */
333 	radio->registers[POWERCFG] &= ~POWERCFG_SEEK;
334 	retval = si470x_set_register(radio, POWERCFG);
335 
336 done:
337 	/* try again, if timed out */
338 	if ((retval == 0) && timed_out)
339 		retval = -EAGAIN;
340 
341 	return retval;
342 }
343 
344 
345 /*
346  * si470x_start - switch on radio
347  */
348 int si470x_start(struct si470x_device *radio)
349 {
350 	int retval;
351 
352 	/* powercfg */
353 	radio->registers[POWERCFG] =
354 		POWERCFG_DMUTE | POWERCFG_ENABLE | POWERCFG_RDSM;
355 	retval = si470x_set_register(radio, POWERCFG);
356 	if (retval < 0)
357 		goto done;
358 
359 	/* sysconfig 1 */
360 	radio->registers[SYSCONFIG1] = SYSCONFIG1_DE;
361 	retval = si470x_set_register(radio, SYSCONFIG1);
362 	if (retval < 0)
363 		goto done;
364 
365 	/* sysconfig 2 */
366 	radio->registers[SYSCONFIG2] =
367 		(0x3f  << 8) |				/* SEEKTH */
368 		((band  << 6) & SYSCONFIG2_BAND)  |	/* BAND */
369 		((space << 4) & SYSCONFIG2_SPACE) |	/* SPACE */
370 		15;					/* VOLUME (max) */
371 	retval = si470x_set_register(radio, SYSCONFIG2);
372 	if (retval < 0)
373 		goto done;
374 
375 	/* reset last channel */
376 	retval = si470x_set_chan(radio,
377 		radio->registers[CHANNEL] & CHANNEL_CHAN);
378 
379 done:
380 	return retval;
381 }
382 
383 
384 /*
385  * si470x_stop - switch off radio
386  */
387 int si470x_stop(struct si470x_device *radio)
388 {
389 	int retval;
390 
391 	/* sysconfig 1 */
392 	radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
393 	retval = si470x_set_register(radio, SYSCONFIG1);
394 	if (retval < 0)
395 		goto done;
396 
397 	/* powercfg */
398 	radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
399 	/* POWERCFG_ENABLE has to automatically go low */
400 	radio->registers[POWERCFG] |= POWERCFG_ENABLE |	POWERCFG_DISABLE;
401 	retval = si470x_set_register(radio, POWERCFG);
402 
403 done:
404 	return retval;
405 }
406 
407 
408 /*
409  * si470x_rds_on - switch on rds reception
410  */
411 int si470x_rds_on(struct si470x_device *radio)
412 {
413 	int retval;
414 
415 	/* sysconfig 1 */
416 	mutex_lock(&radio->lock);
417 	radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDS;
418 	retval = si470x_set_register(radio, SYSCONFIG1);
419 	if (retval < 0)
420 		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
421 	mutex_unlock(&radio->lock);
422 
423 	return retval;
424 }
425 
426 
427 
428 /**************************************************************************
429  * Video4Linux Interface
430  **************************************************************************/
431 
432 /*
433  * si470x_vidioc_queryctrl - enumerate control items
434  */
435 static int si470x_vidioc_queryctrl(struct file *file, void *priv,
436 		struct v4l2_queryctrl *qc)
437 {
438 	struct si470x_device *radio = video_drvdata(file);
439 	int retval = -EINVAL;
440 
441 	/* abort if qc->id is below V4L2_CID_BASE */
442 	if (qc->id < V4L2_CID_BASE)
443 		goto done;
444 
445 	/* search video control */
446 	switch (qc->id) {
447 	case V4L2_CID_AUDIO_VOLUME:
448 		return v4l2_ctrl_query_fill(qc, 0, 15, 1, 15);
449 	case V4L2_CID_AUDIO_MUTE:
450 		return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
451 	}
452 
453 	/* disable unsupported base controls */
454 	/* to satisfy kradio and such apps */
455 	if ((retval == -EINVAL) && (qc->id < V4L2_CID_LASTP1)) {
456 		qc->flags = V4L2_CTRL_FLAG_DISABLED;
457 		retval = 0;
458 	}
459 
460 done:
461 	if (retval < 0)
462 		dev_warn(&radio->videodev->dev,
463 			"query controls failed with %d\n", retval);
464 	return retval;
465 }
466 
467 
468 /*
469  * si470x_vidioc_g_ctrl - get the value of a control
470  */
471 static int si470x_vidioc_g_ctrl(struct file *file, void *priv,
472 		struct v4l2_control *ctrl)
473 {
474 	struct si470x_device *radio = video_drvdata(file);
475 	int retval = 0;
476 
477 	/* safety checks */
478 	retval = si470x_disconnect_check(radio);
479 	if (retval)
480 		goto done;
481 
482 	switch (ctrl->id) {
483 	case V4L2_CID_AUDIO_VOLUME:
484 		ctrl->value = radio->registers[SYSCONFIG2] &
485 				SYSCONFIG2_VOLUME;
486 		break;
487 	case V4L2_CID_AUDIO_MUTE:
488 		ctrl->value = ((radio->registers[POWERCFG] &
489 				POWERCFG_DMUTE) == 0) ? 1 : 0;
490 		break;
491 	default:
492 		retval = -EINVAL;
493 	}
494 
495 done:
496 	if (retval < 0)
497 		dev_warn(&radio->videodev->dev,
498 			"get control failed with %d\n", retval);
499 	return retval;
500 }
501 
502 
503 /*
504  * si470x_vidioc_s_ctrl - set the value of a control
505  */
506 static int si470x_vidioc_s_ctrl(struct file *file, void *priv,
507 		struct v4l2_control *ctrl)
508 {
509 	struct si470x_device *radio = video_drvdata(file);
510 	int retval = 0;
511 
512 	/* safety checks */
513 	retval = si470x_disconnect_check(radio);
514 	if (retval)
515 		goto done;
516 
517 	switch (ctrl->id) {
518 	case V4L2_CID_AUDIO_VOLUME:
519 		radio->registers[SYSCONFIG2] &= ~SYSCONFIG2_VOLUME;
520 		radio->registers[SYSCONFIG2] |= ctrl->value;
521 		retval = si470x_set_register(radio, SYSCONFIG2);
522 		break;
523 	case V4L2_CID_AUDIO_MUTE:
524 		if (ctrl->value == 1)
525 			radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
526 		else
527 			radio->registers[POWERCFG] |= POWERCFG_DMUTE;
528 		retval = si470x_set_register(radio, POWERCFG);
529 		break;
530 	default:
531 		retval = -EINVAL;
532 	}
533 
534 done:
535 	if (retval < 0)
536 		dev_warn(&radio->videodev->dev,
537 			"set control failed with %d\n", retval);
538 	return retval;
539 }
540 
541 
542 /*
543  * si470x_vidioc_g_audio - get audio attributes
544  */
545 static int si470x_vidioc_g_audio(struct file *file, void *priv,
546 		struct v4l2_audio *audio)
547 {
548 	/* driver constants */
549 	audio->index = 0;
550 	strcpy(audio->name, "Radio");
551 	audio->capability = V4L2_AUDCAP_STEREO;
552 	audio->mode = 0;
553 
554 	return 0;
555 }
556 
557 
558 /*
559  * si470x_vidioc_g_tuner - get tuner attributes
560  */
561 static int si470x_vidioc_g_tuner(struct file *file, void *priv,
562 		struct v4l2_tuner *tuner)
563 {
564 	struct si470x_device *radio = video_drvdata(file);
565 	int retval = 0;
566 
567 	/* safety checks */
568 	retval = si470x_disconnect_check(radio);
569 	if (retval)
570 		goto done;
571 
572 	if (tuner->index != 0) {
573 		retval = -EINVAL;
574 		goto done;
575 	}
576 
577 	retval = si470x_get_register(radio, STATUSRSSI);
578 	if (retval < 0)
579 		goto done;
580 
581 	/* driver constants */
582 	strcpy(tuner->name, "FM");
583 	tuner->type = V4L2_TUNER_RADIO;
584 #if defined(CONFIG_USB_SI470X) || defined(CONFIG_USB_SI470X_MODULE)
585 	tuner->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
586 			    V4L2_TUNER_CAP_RDS;
587 #else
588 	tuner->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
589 #endif
590 
591 	/* range limits */
592 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_BAND) >> 6) {
593 	/* 0: 87.5 - 108 MHz (USA, Europe, default) */
594 	default:
595 		tuner->rangelow  =  87.5 * FREQ_MUL;
596 		tuner->rangehigh = 108   * FREQ_MUL;
597 		break;
598 	/* 1: 76   - 108 MHz (Japan wide band) */
599 	case 1:
600 		tuner->rangelow  =  76   * FREQ_MUL;
601 		tuner->rangehigh = 108   * FREQ_MUL;
602 		break;
603 	/* 2: 76   -  90 MHz (Japan) */
604 	case 2:
605 		tuner->rangelow  =  76   * FREQ_MUL;
606 		tuner->rangehigh =  90   * FREQ_MUL;
607 		break;
608 	};
609 
610 	/* stereo indicator == stereo (instead of mono) */
611 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_ST) == 0)
612 		tuner->rxsubchans = V4L2_TUNER_SUB_MONO;
613 	else
614 		tuner->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
615 #if defined(CONFIG_USB_SI470X) || defined(CONFIG_USB_SI470X_MODULE)
616 	/* If there is a reliable method of detecting an RDS channel,
617 	   then this code should check for that before setting this
618 	   RDS subchannel. */
619 	tuner->rxsubchans |= V4L2_TUNER_SUB_RDS;
620 #endif
621 
622 	/* mono/stereo selector */
623 	if ((radio->registers[POWERCFG] & POWERCFG_MONO) == 0)
624 		tuner->audmode = V4L2_TUNER_MODE_STEREO;
625 	else
626 		tuner->audmode = V4L2_TUNER_MODE_MONO;
627 
628 	/* min is worst, max is best; signal:0..0xffff; rssi: 0..0xff */
629 	/* measured in units of db쨉V in 1 db increments (max at ~75 db쨉V) */
630 	tuner->signal = (radio->registers[STATUSRSSI] & STATUSRSSI_RSSI);
631 	/* the ideal factor is 0xffff/75 = 873,8 */
632 	tuner->signal = (tuner->signal * 873) + (8 * tuner->signal / 10);
633 
634 	/* automatic frequency control: -1: freq to low, 1 freq to high */
635 	/* AFCRL does only indicate that freq. differs, not if too low/high */
636 	tuner->afc = (radio->registers[STATUSRSSI] & STATUSRSSI_AFCRL) ? 1 : 0;
637 
638 done:
639 	if (retval < 0)
640 		dev_warn(&radio->videodev->dev,
641 			"get tuner failed with %d\n", retval);
642 	return retval;
643 }
644 
645 
646 /*
647  * si470x_vidioc_s_tuner - set tuner attributes
648  */
649 static int si470x_vidioc_s_tuner(struct file *file, void *priv,
650 		struct v4l2_tuner *tuner)
651 {
652 	struct si470x_device *radio = video_drvdata(file);
653 	int retval = -EINVAL;
654 
655 	/* safety checks */
656 	retval = si470x_disconnect_check(radio);
657 	if (retval)
658 		goto done;
659 
660 	if (tuner->index != 0)
661 		goto done;
662 
663 	/* mono/stereo selector */
664 	switch (tuner->audmode) {
665 	case V4L2_TUNER_MODE_MONO:
666 		radio->registers[POWERCFG] |= POWERCFG_MONO;  /* force mono */
667 		break;
668 	case V4L2_TUNER_MODE_STEREO:
669 		radio->registers[POWERCFG] &= ~POWERCFG_MONO; /* try stereo */
670 		break;
671 	default:
672 		goto done;
673 	}
674 
675 	retval = si470x_set_register(radio, POWERCFG);
676 
677 done:
678 	if (retval < 0)
679 		dev_warn(&radio->videodev->dev,
680 			"set tuner failed with %d\n", retval);
681 	return retval;
682 }
683 
684 
685 /*
686  * si470x_vidioc_g_frequency - get tuner or modulator radio frequency
687  */
688 static int si470x_vidioc_g_frequency(struct file *file, void *priv,
689 		struct v4l2_frequency *freq)
690 {
691 	struct si470x_device *radio = video_drvdata(file);
692 	int retval = 0;
693 
694 	/* safety checks */
695 	retval = si470x_disconnect_check(radio);
696 	if (retval)
697 		goto done;
698 
699 	if (freq->tuner != 0) {
700 		retval = -EINVAL;
701 		goto done;
702 	}
703 
704 	freq->type = V4L2_TUNER_RADIO;
705 	retval = si470x_get_freq(radio, &freq->frequency);
706 
707 done:
708 	if (retval < 0)
709 		dev_warn(&radio->videodev->dev,
710 			"get frequency failed with %d\n", retval);
711 	return retval;
712 }
713 
714 
715 /*
716  * si470x_vidioc_s_frequency - set tuner or modulator radio frequency
717  */
718 static int si470x_vidioc_s_frequency(struct file *file, void *priv,
719 		struct v4l2_frequency *freq)
720 {
721 	struct si470x_device *radio = video_drvdata(file);
722 	int retval = 0;
723 
724 	/* safety checks */
725 	retval = si470x_disconnect_check(radio);
726 	if (retval)
727 		goto done;
728 
729 	if (freq->tuner != 0) {
730 		retval = -EINVAL;
731 		goto done;
732 	}
733 
734 	retval = si470x_set_freq(radio, freq->frequency);
735 
736 done:
737 	if (retval < 0)
738 		dev_warn(&radio->videodev->dev,
739 			"set frequency failed with %d\n", retval);
740 	return retval;
741 }
742 
743 
744 /*
745  * si470x_vidioc_s_hw_freq_seek - set hardware frequency seek
746  */
747 static int si470x_vidioc_s_hw_freq_seek(struct file *file, void *priv,
748 		struct v4l2_hw_freq_seek *seek)
749 {
750 	struct si470x_device *radio = video_drvdata(file);
751 	int retval = 0;
752 
753 	/* safety checks */
754 	retval = si470x_disconnect_check(radio);
755 	if (retval)
756 		goto done;
757 
758 	if (seek->tuner != 0) {
759 		retval = -EINVAL;
760 		goto done;
761 	}
762 
763 	retval = si470x_set_seek(radio, seek->wrap_around, seek->seek_upward);
764 
765 done:
766 	if (retval < 0)
767 		dev_warn(&radio->videodev->dev,
768 			"set hardware frequency seek failed with %d\n", retval);
769 	return retval;
770 }
771 
772 
773 /*
774  * si470x_ioctl_ops - video device ioctl operations
775  */
776 static const struct v4l2_ioctl_ops si470x_ioctl_ops = {
777 	.vidioc_querycap	= si470x_vidioc_querycap,
778 	.vidioc_queryctrl	= si470x_vidioc_queryctrl,
779 	.vidioc_g_ctrl		= si470x_vidioc_g_ctrl,
780 	.vidioc_s_ctrl		= si470x_vidioc_s_ctrl,
781 	.vidioc_g_audio		= si470x_vidioc_g_audio,
782 	.vidioc_g_tuner		= si470x_vidioc_g_tuner,
783 	.vidioc_s_tuner		= si470x_vidioc_s_tuner,
784 	.vidioc_g_frequency	= si470x_vidioc_g_frequency,
785 	.vidioc_s_frequency	= si470x_vidioc_s_frequency,
786 	.vidioc_s_hw_freq_seek	= si470x_vidioc_s_hw_freq_seek,
787 };
788 
789 
790 /*
791  * si470x_viddev_template - video device interface
792  */
793 struct video_device si470x_viddev_template = {
794 	.fops			= &si470x_fops,
795 	.name			= DRIVER_NAME,
796 	.release		= video_device_release,
797 	.ioctl_ops		= &si470x_ioctl_ops,
798 };
799