1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3    Driver for SAA6588 RDS decoder
4
5    (c) 2005 Hans J. Koch
6
7*/
8
9
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/i2c.h>
13#include <linux/types.h>
14#include <linux/videodev2.h>
15#include <linux/init.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/poll.h>
19#include <linux/wait.h>
20#include <linux/uaccess.h>
21
22#include <media/i2c/saa6588.h>
23#include <media/v4l2-device.h>
24
25
26/* insmod options */
27static unsigned int debug;
28static unsigned int xtal;
29static unsigned int mmbs;
30static unsigned int plvl;
31static unsigned int bufblocks = 100;
32
33module_param(debug, int, 0644);
34MODULE_PARM_DESC(debug, "enable debug messages");
35module_param(xtal, int, 0);
36MODULE_PARM_DESC(xtal, "select oscillator frequency (0..3), default 0");
37module_param(mmbs, int, 0);
38MODULE_PARM_DESC(mmbs, "enable MMBS mode: 0=off (default), 1=on");
39module_param(plvl, int, 0);
40MODULE_PARM_DESC(plvl, "select pause level (0..3), default 0");
41module_param(bufblocks, int, 0);
42MODULE_PARM_DESC(bufblocks, "number of buffered blocks, default 100");
43
44MODULE_DESCRIPTION("v4l2 driver module for SAA6588 RDS decoder");
45MODULE_AUTHOR("Hans J. Koch <koch@hjk-az.de>");
46
47MODULE_LICENSE("GPL");
48
49/* ---------------------------------------------------------------------- */
50
51#define UNSET       (-1U)
52#define PREFIX      "saa6588: "
53#define dprintk     if (debug) printk
54
55struct saa6588 {
56	struct v4l2_subdev sd;
57	struct delayed_work work;
58	spinlock_t lock;
59	unsigned char *buffer;
60	unsigned int buf_size;
61	unsigned int rd_index;
62	unsigned int wr_index;
63	unsigned int block_count;
64	unsigned char last_blocknum;
65	wait_queue_head_t read_queue;
66	int data_available_for_read;
67	u8 sync;
68};
69
70static inline struct saa6588 *to_saa6588(struct v4l2_subdev *sd)
71{
72	return container_of(sd, struct saa6588, sd);
73}
74
75/* ---------------------------------------------------------------------- */
76
77/*
78 * SAA6588 defines
79 */
80
81/* Initialization and mode control byte (0w) */
82
83/* bit 0+1 (DAC0/DAC1) */
84#define cModeStandard           0x00
85#define cModeFastPI             0x01
86#define cModeReducedRequest     0x02
87#define cModeInvalid            0x03
88
89/* bit 2 (RBDS) */
90#define cProcessingModeRDS      0x00
91#define cProcessingModeRBDS     0x04
92
93/* bit 3+4 (SYM0/SYM1) */
94#define cErrCorrectionNone      0x00
95#define cErrCorrection2Bits     0x08
96#define cErrCorrection5Bits     0x10
97#define cErrCorrectionNoneRBDS  0x18
98
99/* bit 5 (NWSY) */
100#define cSyncNormal             0x00
101#define cSyncRestart            0x20
102
103/* bit 6 (TSQD) */
104#define cSigQualityDetectOFF    0x00
105#define cSigQualityDetectON     0x40
106
107/* bit 7 (SQCM) */
108#define cSigQualityTriggered    0x00
109#define cSigQualityContinous    0x80
110
111/* Pause level and flywheel control byte (1w) */
112
113/* bits 0..5 (FEB0..FEB5) */
114#define cFlywheelMaxBlocksMask  0x3F
115#define cFlywheelDefault        0x20
116
117/* bits 6+7 (PL0/PL1) */
118#define cPauseLevel_11mV	0x00
119#define cPauseLevel_17mV        0x40
120#define cPauseLevel_27mV        0x80
121#define cPauseLevel_43mV        0xC0
122
123/* Pause time/oscillator frequency/quality detector control byte (1w) */
124
125/* bits 0..4 (SQS0..SQS4) */
126#define cQualityDetectSensMask  0x1F
127#define cQualityDetectDefault   0x0F
128
129/* bit 5 (SOSC) */
130#define cSelectOscFreqOFF	0x00
131#define cSelectOscFreqON	0x20
132
133/* bit 6+7 (PTF0/PTF1) */
134#define cOscFreq_4332kHz	0x00
135#define cOscFreq_8664kHz	0x40
136#define cOscFreq_12996kHz	0x80
137#define cOscFreq_17328kHz	0xC0
138
139/* ---------------------------------------------------------------------- */
140
141static bool block_from_buf(struct saa6588 *s, unsigned char *buf)
142{
143	int i;
144
145	if (s->rd_index == s->wr_index) {
146		if (debug > 2)
147			dprintk(PREFIX "Read: buffer empty.\n");
148		return false;
149	}
150
151	if (debug > 2) {
152		dprintk(PREFIX "Read: ");
153		for (i = s->rd_index; i < s->rd_index + 3; i++)
154			dprintk("0x%02x ", s->buffer[i]);
155	}
156
157	memcpy(buf, &s->buffer[s->rd_index], 3);
158
159	s->rd_index += 3;
160	if (s->rd_index >= s->buf_size)
161		s->rd_index = 0;
162	s->block_count--;
163
164	if (debug > 2)
165		dprintk("%d blocks total.\n", s->block_count);
166
167	return true;
168}
169
170static void read_from_buf(struct saa6588 *s, struct saa6588_command *a)
171{
172	unsigned char __user *buf_ptr = a->buffer;
173	unsigned char buf[3];
174	unsigned long flags;
175	unsigned int rd_blocks;
176	unsigned int i;
177
178	a->result = 0;
179	if (!a->buffer)
180		return;
181
182	while (!a->nonblocking && !s->data_available_for_read) {
183		int ret = wait_event_interruptible(s->read_queue,
184					     s->data_available_for_read);
185		if (ret == -ERESTARTSYS) {
186			a->result = -EINTR;
187			return;
188		}
189	}
190
191	rd_blocks = a->block_count;
192	spin_lock_irqsave(&s->lock, flags);
193	if (rd_blocks > s->block_count)
194		rd_blocks = s->block_count;
195	spin_unlock_irqrestore(&s->lock, flags);
196
197	if (!rd_blocks)
198		return;
199
200	for (i = 0; i < rd_blocks; i++) {
201		bool got_block;
202
203		spin_lock_irqsave(&s->lock, flags);
204		got_block = block_from_buf(s, buf);
205		spin_unlock_irqrestore(&s->lock, flags);
206		if (!got_block)
207			break;
208		if (copy_to_user(buf_ptr, buf, 3)) {
209			a->result = -EFAULT;
210			return;
211		}
212		buf_ptr += 3;
213		a->result += 3;
214	}
215	spin_lock_irqsave(&s->lock, flags);
216	s->data_available_for_read = (s->block_count > 0);
217	spin_unlock_irqrestore(&s->lock, flags);
218}
219
220static void block_to_buf(struct saa6588 *s, unsigned char *blockbuf)
221{
222	unsigned int i;
223
224	if (debug > 3)
225		dprintk(PREFIX "New block: ");
226
227	for (i = 0; i < 3; ++i) {
228		if (debug > 3)
229			dprintk("0x%02x ", blockbuf[i]);
230		s->buffer[s->wr_index] = blockbuf[i];
231		s->wr_index++;
232	}
233
234	if (s->wr_index >= s->buf_size)
235		s->wr_index = 0;
236
237	if (s->wr_index == s->rd_index) {
238		s->rd_index += 3;
239		if (s->rd_index >= s->buf_size)
240			s->rd_index = 0;
241	} else
242		s->block_count++;
243
244	if (debug > 3)
245		dprintk("%d blocks total.\n", s->block_count);
246}
247
248static void saa6588_i2c_poll(struct saa6588 *s)
249{
250	struct i2c_client *client = v4l2_get_subdevdata(&s->sd);
251	unsigned long flags;
252	unsigned char tmpbuf[6];
253	unsigned char blocknum;
254	unsigned char tmp;
255
256	/* Although we only need 3 bytes, we have to read at least 6.
257	   SAA6588 returns garbage otherwise. */
258	if (6 != i2c_master_recv(client, &tmpbuf[0], 6)) {
259		if (debug > 1)
260			dprintk(PREFIX "read error!\n");
261		return;
262	}
263
264	s->sync = tmpbuf[0] & 0x10;
265	if (!s->sync)
266		return;
267	blocknum = tmpbuf[0] >> 5;
268	if (blocknum == s->last_blocknum) {
269		if (debug > 3)
270			dprintk("Saw block %d again.\n", blocknum);
271		return;
272	}
273
274	s->last_blocknum = blocknum;
275
276	/*
277	   Byte order according to v4l2 specification:
278
279	   Byte 0: Least Significant Byte of RDS Block
280	   Byte 1: Most Significant Byte of RDS Block
281	   Byte 2 Bit 7: Error bit. Indicates that an uncorrectable error
282	   occurred during reception of this block.
283	   Bit 6: Corrected bit. Indicates that an error was
284	   corrected for this data block.
285	   Bits 5-3: Same as bits 0-2.
286	   Bits 2-0: Block number.
287
288	   SAA6588 byte order is Status-MSB-LSB, so we have to swap the
289	   first and the last of the 3 bytes block.
290	 */
291
292	swap(tmpbuf[2], tmpbuf[0]);
293
294	/* Map 'Invalid block E' to 'Invalid Block' */
295	if (blocknum == 6)
296		blocknum = V4L2_RDS_BLOCK_INVALID;
297	/* And if are not in mmbs mode, then 'Block E' is also mapped
298	   to 'Invalid Block'. As far as I can tell MMBS is discontinued,
299	   and if there is ever a need to support E blocks, then please
300	   contact the linux-media mailinglist. */
301	else if (!mmbs && blocknum == 5)
302		blocknum = V4L2_RDS_BLOCK_INVALID;
303	tmp = blocknum;
304	tmp |= blocknum << 3;	/* Received offset == Offset Name (OK ?) */
305	if ((tmpbuf[2] & 0x03) == 0x03)
306		tmp |= V4L2_RDS_BLOCK_ERROR;	 /* uncorrectable error */
307	else if ((tmpbuf[2] & 0x03) != 0x00)
308		tmp |= V4L2_RDS_BLOCK_CORRECTED; /* corrected error */
309	tmpbuf[2] = tmp;	/* Is this enough ? Should we also check other bits ? */
310
311	spin_lock_irqsave(&s->lock, flags);
312	block_to_buf(s, tmpbuf);
313	spin_unlock_irqrestore(&s->lock, flags);
314	s->data_available_for_read = 1;
315	wake_up_interruptible(&s->read_queue);
316}
317
318static void saa6588_work(struct work_struct *work)
319{
320	struct saa6588 *s = container_of(work, struct saa6588, work.work);
321
322	saa6588_i2c_poll(s);
323	schedule_delayed_work(&s->work, msecs_to_jiffies(20));
324}
325
326static void saa6588_configure(struct saa6588 *s)
327{
328	struct i2c_client *client = v4l2_get_subdevdata(&s->sd);
329	unsigned char buf[3];
330	int rc;
331
332	buf[0] = cSyncRestart;
333	if (mmbs)
334		buf[0] |= cProcessingModeRBDS;
335
336	buf[1] = cFlywheelDefault;
337	switch (plvl) {
338	case 0:
339		buf[1] |= cPauseLevel_11mV;
340		break;
341	case 1:
342		buf[1] |= cPauseLevel_17mV;
343		break;
344	case 2:
345		buf[1] |= cPauseLevel_27mV;
346		break;
347	case 3:
348		buf[1] |= cPauseLevel_43mV;
349		break;
350	default:		/* nothing */
351		break;
352	}
353
354	buf[2] = cQualityDetectDefault | cSelectOscFreqON;
355
356	switch (xtal) {
357	case 0:
358		buf[2] |= cOscFreq_4332kHz;
359		break;
360	case 1:
361		buf[2] |= cOscFreq_8664kHz;
362		break;
363	case 2:
364		buf[2] |= cOscFreq_12996kHz;
365		break;
366	case 3:
367		buf[2] |= cOscFreq_17328kHz;
368		break;
369	default:		/* nothing */
370		break;
371	}
372
373	dprintk(PREFIX "writing: 0w=0x%02x 1w=0x%02x 2w=0x%02x\n",
374		buf[0], buf[1], buf[2]);
375
376	rc = i2c_master_send(client, buf, 3);
377	if (rc != 3)
378		printk(PREFIX "i2c i/o error: rc == %d (should be 3)\n", rc);
379}
380
381/* ---------------------------------------------------------------------- */
382
383static long saa6588_command(struct v4l2_subdev *sd, unsigned int cmd, void *arg)
384{
385	struct saa6588 *s = to_saa6588(sd);
386	struct saa6588_command *a = arg;
387
388	switch (cmd) {
389		/* --- close() for /dev/radio --- */
390	case SAA6588_CMD_CLOSE:
391		s->data_available_for_read = 1;
392		wake_up_interruptible(&s->read_queue);
393		s->data_available_for_read = 0;
394		a->result = 0;
395		break;
396		/* --- read() for /dev/radio --- */
397	case SAA6588_CMD_READ:
398		read_from_buf(s, a);
399		break;
400		/* --- poll() for /dev/radio --- */
401	case SAA6588_CMD_POLL:
402		a->poll_mask = 0;
403		if (s->data_available_for_read)
404			a->poll_mask |= EPOLLIN | EPOLLRDNORM;
405		poll_wait(a->instance, &s->read_queue, a->event_list);
406		break;
407
408	default:
409		/* nothing */
410		return -ENOIOCTLCMD;
411	}
412	return 0;
413}
414
415static int saa6588_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *vt)
416{
417	struct saa6588 *s = to_saa6588(sd);
418
419	vt->capability |= V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO;
420	if (s->sync)
421		vt->rxsubchans |= V4L2_TUNER_SUB_RDS;
422	return 0;
423}
424
425static int saa6588_s_tuner(struct v4l2_subdev *sd, const struct v4l2_tuner *vt)
426{
427	struct saa6588 *s = to_saa6588(sd);
428
429	saa6588_configure(s);
430	return 0;
431}
432
433/* ----------------------------------------------------------------------- */
434
435static const struct v4l2_subdev_core_ops saa6588_core_ops = {
436	.command = saa6588_command,
437};
438
439static const struct v4l2_subdev_tuner_ops saa6588_tuner_ops = {
440	.g_tuner = saa6588_g_tuner,
441	.s_tuner = saa6588_s_tuner,
442};
443
444static const struct v4l2_subdev_ops saa6588_ops = {
445	.core = &saa6588_core_ops,
446	.tuner = &saa6588_tuner_ops,
447};
448
449/* ---------------------------------------------------------------------- */
450
451static int saa6588_probe(struct i2c_client *client)
452{
453	struct saa6588 *s;
454	struct v4l2_subdev *sd;
455
456	v4l_info(client, "saa6588 found @ 0x%x (%s)\n",
457			client->addr << 1, client->adapter->name);
458
459	s = devm_kzalloc(&client->dev, sizeof(*s), GFP_KERNEL);
460	if (s == NULL)
461		return -ENOMEM;
462
463	s->buf_size = bufblocks * 3;
464
465	s->buffer = devm_kzalloc(&client->dev, s->buf_size, GFP_KERNEL);
466	if (s->buffer == NULL)
467		return -ENOMEM;
468	sd = &s->sd;
469	v4l2_i2c_subdev_init(sd, client, &saa6588_ops);
470	spin_lock_init(&s->lock);
471	s->block_count = 0;
472	s->wr_index = 0;
473	s->rd_index = 0;
474	s->last_blocknum = 0xff;
475	init_waitqueue_head(&s->read_queue);
476	s->data_available_for_read = 0;
477
478	saa6588_configure(s);
479
480	/* start polling via eventd */
481	INIT_DELAYED_WORK(&s->work, saa6588_work);
482	schedule_delayed_work(&s->work, 0);
483	return 0;
484}
485
486static void saa6588_remove(struct i2c_client *client)
487{
488	struct v4l2_subdev *sd = i2c_get_clientdata(client);
489	struct saa6588 *s = to_saa6588(sd);
490
491	v4l2_device_unregister_subdev(sd);
492
493	cancel_delayed_work_sync(&s->work);
494}
495
496/* ----------------------------------------------------------------------- */
497
498static const struct i2c_device_id saa6588_id[] = {
499	{ "saa6588", 0 },
500	{ }
501};
502MODULE_DEVICE_TABLE(i2c, saa6588_id);
503
504static struct i2c_driver saa6588_driver = {
505	.driver = {
506		.name	= "saa6588",
507	},
508	.probe		= saa6588_probe,
509	.remove		= saa6588_remove,
510	.id_table	= saa6588_id,
511};
512
513module_i2c_driver(saa6588_driver);
514