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 */
27  static unsigned int debug;
28  static unsigned int xtal;
29  static unsigned int mmbs;
30  static unsigned int plvl;
31  static unsigned int bufblocks = 100;
32  
33  module_param(debug, int, 0644);
34  MODULE_PARM_DESC(debug, "enable debug messages");
35  module_param(xtal, int, 0);
36  MODULE_PARM_DESC(xtal, "select oscillator frequency (0..3), default 0");
37  module_param(mmbs, int, 0);
38  MODULE_PARM_DESC(mmbs, "enable MMBS mode: 0=off (default), 1=on");
39  module_param(plvl, int, 0);
40  MODULE_PARM_DESC(plvl, "select pause level (0..3), default 0");
41  module_param(bufblocks, int, 0);
42  MODULE_PARM_DESC(bufblocks, "number of buffered blocks, default 100");
43  
44  MODULE_DESCRIPTION("v4l2 driver module for SAA6588 RDS decoder");
45  MODULE_AUTHOR("Hans J. Koch <koch@hjk-az.de>");
46  
47  MODULE_LICENSE("GPL");
48  
49  /* ---------------------------------------------------------------------- */
50  
51  #define UNSET       (-1U)
52  #define PREFIX      "saa6588: "
53  #define dprintk     if (debug) printk
54  
55  struct 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  
to_saa6588(struct v4l2_subdev * sd)70  static 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  
block_from_buf(struct saa6588 * s,unsigned char * buf)141  static 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  
read_from_buf(struct saa6588 * s,struct saa6588_command * a)170  static 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  
block_to_buf(struct saa6588 * s,unsigned char * blockbuf)220  static 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  
saa6588_i2c_poll(struct saa6588 * s)248  static 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  
saa6588_work(struct work_struct * work)318  static 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  
saa6588_configure(struct saa6588 * s)326  static 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  
saa6588_command(struct v4l2_subdev * sd,unsigned int cmd,void * arg)383  static 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  
saa6588_g_tuner(struct v4l2_subdev * sd,struct v4l2_tuner * vt)415  static 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  
saa6588_s_tuner(struct v4l2_subdev * sd,const struct v4l2_tuner * vt)425  static 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  
435  static const struct v4l2_subdev_core_ops saa6588_core_ops = {
436  	.command = saa6588_command,
437  };
438  
439  static const struct v4l2_subdev_tuner_ops saa6588_tuner_ops = {
440  	.g_tuner = saa6588_g_tuner,
441  	.s_tuner = saa6588_s_tuner,
442  };
443  
444  static const struct v4l2_subdev_ops saa6588_ops = {
445  	.core = &saa6588_core_ops,
446  	.tuner = &saa6588_tuner_ops,
447  };
448  
449  /* ---------------------------------------------------------------------- */
450  
saa6588_probe(struct i2c_client * client)451  static 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  
saa6588_remove(struct i2c_client * client)486  static 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  
498  static const struct i2c_device_id saa6588_id[] = {
499  	{ "saa6588" },
500  	{ }
501  };
502  MODULE_DEVICE_TABLE(i2c, saa6588_id);
503  
504  static 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  
513  module_i2c_driver(saa6588_driver);
514