xref: /linux/drivers/media/radio/si470x/radio-si470x-common.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
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 	bool timed_out = false;
212 
213 	/* start tuning */
214 	radio->registers[CHANNEL] &= ~CHANNEL_CHAN;
215 	radio->registers[CHANNEL] |= CHANNEL_TUNE | chan;
216 	retval = si470x_set_register(radio, CHANNEL);
217 	if (retval < 0)
218 		goto done;
219 
220 	/* wait till tune operation has completed */
221 	reinit_completion(&radio->completion);
222 	retval = wait_for_completion_timeout(&radio->completion,
223 			msecs_to_jiffies(tune_timeout));
224 	if (!retval)
225 		timed_out = true;
226 
227 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
228 		dev_warn(&radio->videodev.dev, "tune does not complete\n");
229 	if (timed_out)
230 		dev_warn(&radio->videodev.dev,
231 			"tune timed out after %u ms\n", tune_timeout);
232 
233 	/* stop tuning */
234 	radio->registers[CHANNEL] &= ~CHANNEL_TUNE;
235 	retval = si470x_set_register(radio, CHANNEL);
236 
237 done:
238 	return retval;
239 }
240 
241 /*
242  * si470x_get_step - get channel spacing
243  */
244 static unsigned int si470x_get_step(struct si470x_device *radio)
245 {
246 	/* Spacing (kHz) */
247 	switch ((radio->registers[SYSCONFIG2] & SYSCONFIG2_SPACE) >> 4) {
248 	/* 0: 200 kHz (USA, Australia) */
249 	case 0:
250 		return 200 * 16;
251 	/* 1: 100 kHz (Europe, Japan) */
252 	case 1:
253 		return 100 * 16;
254 	/* 2:  50 kHz */
255 	default:
256 		return 50 * 16;
257 	}
258 }
259 
260 
261 /*
262  * si470x_get_freq - get the frequency
263  */
264 static int si470x_get_freq(struct si470x_device *radio, unsigned int *freq)
265 {
266 	int chan, retval;
267 
268 	/* read channel */
269 	retval = si470x_get_register(radio, READCHAN);
270 	chan = radio->registers[READCHAN] & READCHAN_READCHAN;
271 
272 	/* Frequency (MHz) = Spacing (kHz) x Channel + Bottom of Band (MHz) */
273 	*freq = chan * si470x_get_step(radio) + bands[radio->band].rangelow;
274 
275 	return retval;
276 }
277 
278 
279 /*
280  * si470x_set_freq - set the frequency
281  */
282 int si470x_set_freq(struct si470x_device *radio, unsigned int freq)
283 {
284 	unsigned short chan;
285 
286 	freq = clamp(freq, bands[radio->band].rangelow,
287 			   bands[radio->band].rangehigh);
288 	/* Chan = [ Freq (Mhz) - Bottom of Band (MHz) ] / Spacing (kHz) */
289 	chan = (freq - bands[radio->band].rangelow) / si470x_get_step(radio);
290 
291 	return si470x_set_chan(radio, chan);
292 }
293 
294 
295 /*
296  * si470x_set_seek - set seek
297  */
298 static int si470x_set_seek(struct si470x_device *radio,
299 			   const struct v4l2_hw_freq_seek *seek)
300 {
301 	int band, retval;
302 	unsigned int freq;
303 	bool timed_out = false;
304 
305 	/* set band */
306 	if (seek->rangelow || seek->rangehigh) {
307 		for (band = 0; band < ARRAY_SIZE(bands); band++) {
308 			if (bands[band].rangelow  == seek->rangelow &&
309 			    bands[band].rangehigh == seek->rangehigh)
310 				break;
311 		}
312 		if (band == ARRAY_SIZE(bands))
313 			return -EINVAL; /* No matching band found */
314 	} else
315 		band = 1; /* If nothing is specified seek 76 - 108 Mhz */
316 
317 	if (radio->band != band) {
318 		retval = si470x_get_freq(radio, &freq);
319 		if (retval)
320 			return retval;
321 		retval = si470x_set_band(radio, band);
322 		if (retval)
323 			return retval;
324 		retval = si470x_set_freq(radio, freq);
325 		if (retval)
326 			return retval;
327 	}
328 
329 	/* start seeking */
330 	radio->registers[POWERCFG] |= POWERCFG_SEEK;
331 	if (seek->wrap_around)
332 		radio->registers[POWERCFG] &= ~POWERCFG_SKMODE;
333 	else
334 		radio->registers[POWERCFG] |= POWERCFG_SKMODE;
335 	if (seek->seek_upward)
336 		radio->registers[POWERCFG] |= POWERCFG_SEEKUP;
337 	else
338 		radio->registers[POWERCFG] &= ~POWERCFG_SEEKUP;
339 	retval = si470x_set_register(radio, POWERCFG);
340 	if (retval < 0)
341 		return retval;
342 
343 	/* wait till tune operation has completed */
344 	reinit_completion(&radio->completion);
345 	retval = wait_for_completion_timeout(&radio->completion,
346 			msecs_to_jiffies(seek_timeout));
347 	if (!retval)
348 		timed_out = true;
349 
350 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_STC) == 0)
351 		dev_warn(&radio->videodev.dev, "seek does not complete\n");
352 	if (radio->registers[STATUSRSSI] & STATUSRSSI_SF)
353 		dev_warn(&radio->videodev.dev,
354 			"seek failed / band limit reached\n");
355 
356 	/* stop seeking */
357 	radio->registers[POWERCFG] &= ~POWERCFG_SEEK;
358 	retval = si470x_set_register(radio, POWERCFG);
359 
360 	/* try again, if timed out */
361 	if (retval == 0 && timed_out)
362 		return -ENODATA;
363 	return retval;
364 }
365 
366 
367 /*
368  * si470x_start - switch on radio
369  */
370 int si470x_start(struct si470x_device *radio)
371 {
372 	int retval;
373 
374 	/* powercfg */
375 	radio->registers[POWERCFG] =
376 		POWERCFG_DMUTE | POWERCFG_ENABLE | POWERCFG_RDSM;
377 	retval = si470x_set_register(radio, POWERCFG);
378 	if (retval < 0)
379 		goto done;
380 
381 	/* sysconfig 1 */
382 	radio->registers[SYSCONFIG1] =
383 		(de << 11) & SYSCONFIG1_DE;		/* DE*/
384 	retval = si470x_set_register(radio, SYSCONFIG1);
385 	if (retval < 0)
386 		goto done;
387 
388 	/* sysconfig 2 */
389 	radio->registers[SYSCONFIG2] =
390 		(0x1f  << 8) |				/* SEEKTH */
391 		((radio->band << 6) & SYSCONFIG2_BAND) |/* BAND */
392 		((space << 4) & SYSCONFIG2_SPACE) |	/* SPACE */
393 		15;					/* VOLUME (max) */
394 	retval = si470x_set_register(radio, SYSCONFIG2);
395 	if (retval < 0)
396 		goto done;
397 
398 	/* reset last channel */
399 	retval = si470x_set_chan(radio,
400 		radio->registers[CHANNEL] & CHANNEL_CHAN);
401 
402 done:
403 	return retval;
404 }
405 
406 
407 /*
408  * si470x_stop - switch off radio
409  */
410 int si470x_stop(struct si470x_device *radio)
411 {
412 	int retval;
413 
414 	/* sysconfig 1 */
415 	radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
416 	retval = si470x_set_register(radio, SYSCONFIG1);
417 	if (retval < 0)
418 		goto done;
419 
420 	/* powercfg */
421 	radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
422 	/* POWERCFG_ENABLE has to automatically go low */
423 	radio->registers[POWERCFG] |= POWERCFG_ENABLE |	POWERCFG_DISABLE;
424 	retval = si470x_set_register(radio, POWERCFG);
425 
426 done:
427 	return retval;
428 }
429 
430 
431 /*
432  * si470x_rds_on - switch on rds reception
433  */
434 static int si470x_rds_on(struct si470x_device *radio)
435 {
436 	int retval;
437 
438 	/* sysconfig 1 */
439 	radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDS;
440 	retval = si470x_set_register(radio, SYSCONFIG1);
441 	if (retval < 0)
442 		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_RDS;
443 
444 	return retval;
445 }
446 
447 
448 
449 /**************************************************************************
450  * File Operations Interface
451  **************************************************************************/
452 
453 /*
454  * si470x_fops_read - read RDS data
455  */
456 static ssize_t si470x_fops_read(struct file *file, char __user *buf,
457 		size_t count, loff_t *ppos)
458 {
459 	struct si470x_device *radio = video_drvdata(file);
460 	int retval = 0;
461 	unsigned int block_count = 0;
462 
463 	/* switch on rds reception */
464 	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
465 		si470x_rds_on(radio);
466 
467 	/* block if no new data available */
468 	while (radio->wr_index == radio->rd_index) {
469 		if (file->f_flags & O_NONBLOCK) {
470 			retval = -EWOULDBLOCK;
471 			goto done;
472 		}
473 		if (wait_event_interruptible(radio->read_queue,
474 			radio->wr_index != radio->rd_index) < 0) {
475 			retval = -EINTR;
476 			goto done;
477 		}
478 	}
479 
480 	/* calculate block count from byte count */
481 	count /= 3;
482 
483 	/* copy RDS block out of internal buffer and to user buffer */
484 	while (block_count < count) {
485 		if (radio->rd_index == radio->wr_index)
486 			break;
487 
488 		/* always transfer rds complete blocks */
489 		if (copy_to_user(buf, &radio->buffer[radio->rd_index], 3))
490 			/* retval = -EFAULT; */
491 			break;
492 
493 		/* increment and wrap read pointer */
494 		radio->rd_index += 3;
495 		if (radio->rd_index >= radio->buf_size)
496 			radio->rd_index = 0;
497 
498 		/* increment counters */
499 		block_count++;
500 		buf += 3;
501 		retval += 3;
502 	}
503 
504 done:
505 	return retval;
506 }
507 
508 
509 /*
510  * si470x_fops_poll - poll RDS data
511  */
512 static unsigned int si470x_fops_poll(struct file *file,
513 		struct poll_table_struct *pts)
514 {
515 	struct si470x_device *radio = video_drvdata(file);
516 	unsigned long req_events = poll_requested_events(pts);
517 	int retval = v4l2_ctrl_poll(file, pts);
518 
519 	if (req_events & (POLLIN | POLLRDNORM)) {
520 		/* switch on rds reception */
521 		if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
522 			si470x_rds_on(radio);
523 
524 		poll_wait(file, &radio->read_queue, pts);
525 
526 		if (radio->rd_index != radio->wr_index)
527 			retval |= POLLIN | POLLRDNORM;
528 	}
529 
530 	return retval;
531 }
532 
533 
534 /*
535  * si470x_fops - file operations interface
536  */
537 static const struct v4l2_file_operations si470x_fops = {
538 	.owner			= THIS_MODULE,
539 	.read			= si470x_fops_read,
540 	.poll			= si470x_fops_poll,
541 	.unlocked_ioctl		= video_ioctl2,
542 	.open			= si470x_fops_open,
543 	.release		= si470x_fops_release,
544 };
545 
546 
547 
548 /**************************************************************************
549  * Video4Linux Interface
550  **************************************************************************/
551 
552 
553 static int si470x_s_ctrl(struct v4l2_ctrl *ctrl)
554 {
555 	struct si470x_device *radio =
556 		container_of(ctrl->handler, struct si470x_device, hdl);
557 
558 	switch (ctrl->id) {
559 	case V4L2_CID_AUDIO_VOLUME:
560 		radio->registers[SYSCONFIG2] &= ~SYSCONFIG2_VOLUME;
561 		radio->registers[SYSCONFIG2] |= ctrl->val;
562 		return si470x_set_register(radio, SYSCONFIG2);
563 	case V4L2_CID_AUDIO_MUTE:
564 		if (ctrl->val)
565 			radio->registers[POWERCFG] &= ~POWERCFG_DMUTE;
566 		else
567 			radio->registers[POWERCFG] |= POWERCFG_DMUTE;
568 		return si470x_set_register(radio, POWERCFG);
569 	default:
570 		return -EINVAL;
571 	}
572 }
573 
574 
575 /*
576  * si470x_vidioc_g_tuner - get tuner attributes
577  */
578 static int si470x_vidioc_g_tuner(struct file *file, void *priv,
579 		struct v4l2_tuner *tuner)
580 {
581 	struct si470x_device *radio = video_drvdata(file);
582 	int retval = 0;
583 
584 	if (tuner->index != 0)
585 		return -EINVAL;
586 
587 	if (!radio->status_rssi_auto_update) {
588 		retval = si470x_get_register(radio, STATUSRSSI);
589 		if (retval < 0)
590 			return retval;
591 	}
592 
593 	/* driver constants */
594 	strcpy(tuner->name, "FM");
595 	tuner->type = V4L2_TUNER_RADIO;
596 	tuner->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
597 			    V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO |
598 			    V4L2_TUNER_CAP_HWSEEK_BOUNDED |
599 			    V4L2_TUNER_CAP_HWSEEK_WRAP;
600 	tuner->rangelow  =  76 * FREQ_MUL;
601 	tuner->rangehigh = 108 * FREQ_MUL;
602 
603 	/* stereo indicator == stereo (instead of mono) */
604 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_ST) == 0)
605 		tuner->rxsubchans = V4L2_TUNER_SUB_MONO;
606 	else
607 		tuner->rxsubchans = V4L2_TUNER_SUB_STEREO;
608 	/* If there is a reliable method of detecting an RDS channel,
609 	   then this code should check for that before setting this
610 	   RDS subchannel. */
611 	tuner->rxsubchans |= V4L2_TUNER_SUB_RDS;
612 
613 	/* mono/stereo selector */
614 	if ((radio->registers[POWERCFG] & POWERCFG_MONO) == 0)
615 		tuner->audmode = V4L2_TUNER_MODE_STEREO;
616 	else
617 		tuner->audmode = V4L2_TUNER_MODE_MONO;
618 
619 	/* min is worst, max is best; signal:0..0xffff; rssi: 0..0xff */
620 	/* measured in units of dbµV in 1 db increments (max at ~75 dbµV) */
621 	tuner->signal = (radio->registers[STATUSRSSI] & STATUSRSSI_RSSI);
622 	/* the ideal factor is 0xffff/75 = 873,8 */
623 	tuner->signal = (tuner->signal * 873) + (8 * tuner->signal / 10);
624 	if (tuner->signal > 0xffff)
625 		tuner->signal = 0xffff;
626 
627 	/* automatic frequency control: -1: freq to low, 1 freq to high */
628 	/* AFCRL does only indicate that freq. differs, not if too low/high */
629 	tuner->afc = (radio->registers[STATUSRSSI] & STATUSRSSI_AFCRL) ? 1 : 0;
630 
631 	return retval;
632 }
633 
634 
635 /*
636  * si470x_vidioc_s_tuner - set tuner attributes
637  */
638 static int si470x_vidioc_s_tuner(struct file *file, void *priv,
639 		const struct v4l2_tuner *tuner)
640 {
641 	struct si470x_device *radio = video_drvdata(file);
642 
643 	if (tuner->index != 0)
644 		return -EINVAL;
645 
646 	/* mono/stereo selector */
647 	switch (tuner->audmode) {
648 	case V4L2_TUNER_MODE_MONO:
649 		radio->registers[POWERCFG] |= POWERCFG_MONO;  /* force mono */
650 		break;
651 	case V4L2_TUNER_MODE_STEREO:
652 	default:
653 		radio->registers[POWERCFG] &= ~POWERCFG_MONO; /* try stereo */
654 		break;
655 	}
656 
657 	return si470x_set_register(radio, POWERCFG);
658 }
659 
660 
661 /*
662  * si470x_vidioc_g_frequency - get tuner or modulator radio frequency
663  */
664 static int si470x_vidioc_g_frequency(struct file *file, void *priv,
665 		struct v4l2_frequency *freq)
666 {
667 	struct si470x_device *radio = video_drvdata(file);
668 
669 	if (freq->tuner != 0)
670 		return -EINVAL;
671 
672 	freq->type = V4L2_TUNER_RADIO;
673 	return si470x_get_freq(radio, &freq->frequency);
674 }
675 
676 
677 /*
678  * si470x_vidioc_s_frequency - set tuner or modulator radio frequency
679  */
680 static int si470x_vidioc_s_frequency(struct file *file, void *priv,
681 		const struct v4l2_frequency *freq)
682 {
683 	struct si470x_device *radio = video_drvdata(file);
684 	int retval;
685 
686 	if (freq->tuner != 0)
687 		return -EINVAL;
688 
689 	if (freq->frequency < bands[radio->band].rangelow ||
690 	    freq->frequency > bands[radio->band].rangehigh) {
691 		/* Switch to band 1 which covers everything we support */
692 		retval = si470x_set_band(radio, 1);
693 		if (retval)
694 			return retval;
695 	}
696 	return si470x_set_freq(radio, freq->frequency);
697 }
698 
699 
700 /*
701  * si470x_vidioc_s_hw_freq_seek - set hardware frequency seek
702  */
703 static int si470x_vidioc_s_hw_freq_seek(struct file *file, void *priv,
704 		const struct v4l2_hw_freq_seek *seek)
705 {
706 	struct si470x_device *radio = video_drvdata(file);
707 
708 	if (seek->tuner != 0)
709 		return -EINVAL;
710 
711 	if (file->f_flags & O_NONBLOCK)
712 		return -EWOULDBLOCK;
713 
714 	return si470x_set_seek(radio, seek);
715 }
716 
717 /*
718  * si470x_vidioc_enum_freq_bands - enumerate supported bands
719  */
720 static int si470x_vidioc_enum_freq_bands(struct file *file, void *priv,
721 					 struct v4l2_frequency_band *band)
722 {
723 	if (band->tuner != 0)
724 		return -EINVAL;
725 	if (band->index >= ARRAY_SIZE(bands))
726 		return -EINVAL;
727 	*band = bands[band->index];
728 	return 0;
729 }
730 
731 const struct v4l2_ctrl_ops si470x_ctrl_ops = {
732 	.s_ctrl = si470x_s_ctrl,
733 };
734 
735 /*
736  * si470x_ioctl_ops - video device ioctl operations
737  */
738 static const struct v4l2_ioctl_ops si470x_ioctl_ops = {
739 	.vidioc_querycap	= si470x_vidioc_querycap,
740 	.vidioc_g_tuner		= si470x_vidioc_g_tuner,
741 	.vidioc_s_tuner		= si470x_vidioc_s_tuner,
742 	.vidioc_g_frequency	= si470x_vidioc_g_frequency,
743 	.vidioc_s_frequency	= si470x_vidioc_s_frequency,
744 	.vidioc_s_hw_freq_seek	= si470x_vidioc_s_hw_freq_seek,
745 	.vidioc_enum_freq_bands = si470x_vidioc_enum_freq_bands,
746 	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
747 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
748 };
749 
750 
751 /*
752  * si470x_viddev_template - video device interface
753  */
754 struct video_device si470x_viddev_template = {
755 	.fops			= &si470x_fops,
756 	.name			= DRIVER_NAME,
757 	.release		= video_device_release_empty,
758 	.ioctl_ops		= &si470x_ioctl_ops,
759 };
760