text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
      Driver for SAA6588 RDS decoder
  
      (c) 2005 Hans J. Koch
  
  */
  
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/i2c.h>
  #include <linux/types.h>
  #include <linux/videodev2.h>
  #include <linux/init.h>
  #include <linux/errno.h>
  #include <linux/slab.h>
  #include <linux/poll.h>
  #include <linux/wait.h>
  #include <linux/uaccess.h>
  
  #include <media/i2c/saa6588.h>
  #include <media/v4l2-device.h>
  
  
  /* insmod options */
  static unsigned int debug;
  static unsigned int xtal;
  static unsigned int mmbs;
  static unsigned int plvl;
  static unsigned int bufblocks = 100;
  
  module_param(debug, int, 0644);
  MODULE_PARM_DESC(debug, "enable debug messages");
  module_param(xtal, int, 0);
  MODULE_PARM_DESC(xtal, "select oscillator frequency (0..3), default 0");
  module_param(mmbs, int, 0);
  MODULE_PARM_DESC(mmbs, "enable MMBS mode: 0=off (default), 1=on");
  module_param(plvl, int, 0);
  MODULE_PARM_DESC(plvl, "select pause level (0..3), default 0");
  module_param(bufblocks, int, 0);
  MODULE_PARM_DESC(bufblocks, "number of buffered blocks, default 100");
  
  MODULE_DESCRIPTION("v4l2 driver module for SAA6588 RDS decoder");
  MODULE_AUTHOR("Hans J. Koch <koch@hjk-az.de>");
  
  MODULE_LICENSE("GPL");
  
  /* ---------------------------------------------------------------------- */
  
  #define UNSET       (-1U)
  #define PREFIX      "saa6588: "
  #define dprintk     if (debug) printk
  
  struct saa6588 {
  	struct v4l2_subdev sd;
  	struct delayed_work work;
  	spinlock_t lock;
  	unsigned char *buffer;
  	unsigned int buf_size;
  	unsigned int rd_index;
  	unsigned int wr_index;
  	unsigned int block_count;
  	unsigned char last_blocknum;
  	wait_queue_head_t read_queue;
  	int data_available_for_read;
  	u8 sync;
  };
  
  static inline struct saa6588 *to_saa6588(struct v4l2_subdev *sd)
  {
  	return container_of(sd, struct saa6588, sd);
  }
  
  /* ---------------------------------------------------------------------- */
  
  /*
   * SAA6588 defines
   */
  
  /* Initialization and mode control byte (0w) */
  
  /* bit 0+1 (DAC0/DAC1) */
  #define cModeStandard           0x00
  #define cModeFastPI             0x01
  #define cModeReducedRequest     0x02
  #define cModeInvalid            0x03
  
  /* bit 2 (RBDS) */
  #define cProcessingModeRDS      0x00
  #define cProcessingModeRBDS     0x04
  
  /* bit 3+4 (SYM0/SYM1) */
  #define cErrCorrectionNone      0x00
  #define cErrCorrection2Bits     0x08
  #define cErrCorrection5Bits     0x10
  #define cErrCorrectionNoneRBDS  0x18
  
  /* bit 5 (NWSY) */
  #define cSyncNormal             0x00
  #define cSyncRestart            0x20
  
  /* bit 6 (TSQD) */
  #define cSigQualityDetectOFF    0x00
  #define cSigQualityDetectON     0x40
  
  /* bit 7 (SQCM) */
  #define cSigQualityTriggered    0x00
  #define cSigQualityContinous    0x80
  
  /* Pause level and flywheel control byte (1w) */
  
  /* bits 0..5 (FEB0..FEB5) */
  #define cFlywheelMaxBlocksMask  0x3F
  #define cFlywheelDefault        0x20
  
  /* bits 6+7 (PL0/PL1) */
  #define cPauseLevel_11mV	0x00
  #define cPauseLevel_17mV        0x40
  #define cPauseLevel_27mV        0x80
  #define cPauseLevel_43mV        0xC0
  
  /* Pause time/oscillator frequency/quality detector control byte (1w) */
  
  /* bits 0..4 (SQS0..SQS4) */
  #define cQualityDetectSensMask  0x1F
  #define cQualityDetectDefault   0x0F
  
  /* bit 5 (SOSC) */
  #define cSelectOscFreqOFF	0x00
  #define cSelectOscFreqON	0x20
  
  /* bit 6+7 (PTF0/PTF1) */
  #define cOscFreq_4332kHz	0x00
  #define cOscFreq_8664kHz	0x40
  #define cOscFreq_12996kHz	0x80
  #define cOscFreq_17328kHz	0xC0
  
  /* ---------------------------------------------------------------------- */
  
  static bool block_from_buf(struct saa6588 *s, unsigned char *buf)
  {
  	int i;
  
  	if (s->rd_index == s->wr_index) {
  		if (debug > 2)
  			dprintk(PREFIX "Read: buffer empty.\n");
  		return false;
  	}
  
  	if (debug > 2) {
  		dprintk(PREFIX "Read: ");
  		for (i = s->rd_index; i < s->rd_index + 3; i++)
  			dprintk("0x%02x ", s->buffer[i]);
  	}
  
  	memcpy(buf, &s->buffer[s->rd_index], 3);
  
  	s->rd_index += 3;
  	if (s->rd_index >= s->buf_size)
  		s->rd_index = 0;
  	s->block_count--;
  
  	if (debug > 2)
  		dprintk("%d blocks total.\n", s->block_count);
  
  	return true;
  }
  
  static void read_from_buf(struct saa6588 *s, struct saa6588_command *a)
  {
  	unsigned char __user *buf_ptr = a->buffer;
  	unsigned char buf[3];
  	unsigned long flags;
  	unsigned int rd_blocks;
  	unsigned int i;
  
  	a->result = 0;
  	if (!a->buffer)
  		return;
  
  	while (!a->nonblocking && !s->data_available_for_read) {
  		int ret = wait_event_interruptible(s->read_queue,
  					     s->data_available_for_read);
  		if (ret == -ERESTARTSYS) {
  			a->result = -EINTR;
  			return;
  		}
  	}
  
  	rd_blocks = a->block_count;
  	spin_lock_irqsave(&s->lock, flags);
  	if (rd_blocks > s->block_count)
  		rd_blocks = s->block_count;
  	spin_unlock_irqrestore(&s->lock, flags);
  
  	if (!rd_blocks)
  		return;
  
  	for (i = 0; i < rd_blocks; i++) {
  		bool got_block;
  
  		spin_lock_irqsave(&s->lock, flags);
  		got_block = block_from_buf(s, buf);
  		spin_unlock_irqrestore(&s->lock, flags);
  		if (!got_block)
  			break;
  		if (copy_to_user(buf_ptr, buf, 3)) {
  			a->result = -EFAULT;
  			return;
  		}
  		buf_ptr += 3;
  		a->result += 3;
  	}
  	spin_lock_irqsave(&s->lock, flags);
  	s->data_available_for_read = (s->block_count > 0);
  	spin_unlock_irqrestore(&s->lock, flags);
  }
  
  static void block_to_buf(struct saa6588 *s, unsigned char *blockbuf)
  {
  	unsigned int i;
  
  	if (debug > 3)
  		dprintk(PREFIX "New block: ");
  
  	for (i = 0; i < 3; ++i) {
  		if (debug > 3)
  			dprintk("0x%02x ", blockbuf[i]);
  		s->buffer[s->wr_index] = blockbuf[i];
  		s->wr_index++;
  	}
  
  	if (s->wr_index >= s->buf_size)
  		s->wr_index = 0;
  
  	if (s->wr_index == s->rd_index) {
  		s->rd_index += 3;
  		if (s->rd_index >= s->buf_size)
  			s->rd_index = 0;
  	} else
  		s->block_count++;
  
  	if (debug > 3)
  		dprintk("%d blocks total.\n", s->block_count);
  }
  
  static void saa6588_i2c_poll(struct saa6588 *s)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&s->sd);
  	unsigned long flags;
  	unsigned char tmpbuf[6];
  	unsigned char blocknum;
  	unsigned char tmp;
  
  	/* Although we only need 3 bytes, we have to read at least 6.
  	   SAA6588 returns garbage otherwise. */
  	if (6 != i2c_master_recv(client, &tmpbuf[0], 6)) {
  		if (debug > 1)
  			dprintk(PREFIX "read error!\n");
  		return;
  	}
  
  	s->sync = tmpbuf[0] & 0x10;
  	if (!s->sync)
  		return;
  	blocknum = tmpbuf[0] >> 5;
  	if (blocknum == s->last_blocknum) {
  		if (debug > 3)
  			dprintk("Saw block %d again.\n", blocknum);
  		return;
  	}
  
  	s->last_blocknum = blocknum;
  
  	/*
  	   Byte order according to v4l2 specification:
  
  	   Byte 0: Least Significant Byte of RDS Block
  	   Byte 1: Most Significant Byte of RDS Block
  	   Byte 2 Bit 7: Error bit. Indicates that an uncorrectable error
  	   occurred during reception of this block.
  	   Bit 6: Corrected bit. Indicates that an error was
  	   corrected for this data block.
  	   Bits 5-3: Same as bits 0-2.
  	   Bits 2-0: Block number.
  
  	   SAA6588 byte order is Status-MSB-LSB, so we have to swap the
  	   first and the last of the 3 bytes block.
  	 */
  
  	swap(tmpbuf[2], tmpbuf[0]);
  
  	/* Map 'Invalid block E' to 'Invalid Block' */
  	if (blocknum == 6)
  		blocknum = V4L2_RDS_BLOCK_INVALID;
  	/* And if are not in mmbs mode, then 'Block E' is also mapped
  	   to 'Invalid Block'. As far as I can tell MMBS is discontinued,
  	   and if there is ever a need to support E blocks, then please
  	   contact the linux-media mailinglist. */
  	else if (!mmbs && blocknum == 5)
  		blocknum = V4L2_RDS_BLOCK_INVALID;
  	tmp = blocknum;
  	tmp |= blocknum << 3;	/* Received offset == Offset Name (OK ?) */
  	if ((tmpbuf[2] & 0x03) == 0x03)
  		tmp |= V4L2_RDS_BLOCK_ERROR;	 /* uncorrectable error */
  	else if ((tmpbuf[2] & 0x03) != 0x00)
  		tmp |= V4L2_RDS_BLOCK_CORRECTED; /* corrected error */
  	tmpbuf[2] = tmp;	/* Is this enough ? Should we also check other bits ? */
  
  	spin_lock_irqsave(&s->lock, flags);
  	block_to_buf(s, tmpbuf);
  	spin_unlock_irqrestore(&s->lock, flags);
  	s->data_available_for_read = 1;
  	wake_up_interruptible(&s->read_queue);
  }
  
  static void saa6588_work(struct work_struct *work)
  {
  	struct saa6588 *s = container_of(work, struct saa6588, work.work);
  
  	saa6588_i2c_poll(s);
  	schedule_delayed_work(&s->work, msecs_to_jiffies(20));
  }
  
  static void saa6588_configure(struct saa6588 *s)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&s->sd);
  	unsigned char buf[3];
  	int rc;
  
  	buf[0] = cSyncRestart;
  	if (mmbs)
  		buf[0] |= cProcessingModeRBDS;
  
  	buf[1] = cFlywheelDefault;
  	switch (plvl) {
  	case 0:
  		buf[1] |= cPauseLevel_11mV;
  		break;
  	case 1:
  		buf[1] |= cPauseLevel_17mV;
  		break;
  	case 2:
  		buf[1] |= cPauseLevel_27mV;
  		break;
  	case 3:
  		buf[1] |= cPauseLevel_43mV;
  		break;
  	default:		/* nothing */
  		break;
  	}
  
  	buf[2] = cQualityDetectDefault | cSelectOscFreqON;
  
  	switch (xtal) {
  	case 0:
  		buf[2] |= cOscFreq_4332kHz;
  		break;
  	case 1:
  		buf[2] |= cOscFreq_8664kHz;
  		break;
  	case 2:
  		buf[2] |= cOscFreq_12996kHz;
  		break;
  	case 3:
  		buf[2] |= cOscFreq_17328kHz;
  		break;
  	default:		/* nothing */
  		break;
  	}
  
  	dprintk(PREFIX "writing: 0w=0x%02x 1w=0x%02x 2w=0x%02x\n",
  		buf[0], buf[1], buf[2]);
  
  	rc = i2c_master_send(client, buf, 3);
  	if (rc != 3)
  		printk(PREFIX "i2c i/o error: rc == %d (should be 3)\n", rc);
  }
  
  /* ---------------------------------------------------------------------- */
  
  static long saa6588_command(struct v4l2_subdev *sd, unsigned int cmd, void *arg)
  {
  	struct saa6588 *s = to_saa6588(sd);
  	struct saa6588_command *a = arg;
  
  	switch (cmd) {
  		/* --- close() for /dev/radio --- */
  	case SAA6588_CMD_CLOSE:
  		s->data_available_for_read = 1;
  		wake_up_interruptible(&s->read_queue);
  		s->data_available_for_read = 0;
  		a->result = 0;
  		break;
  		/* --- read() for /dev/radio --- */
  	case SAA6588_CMD_READ:
  		read_from_buf(s, a);
  		break;
  		/* --- poll() for /dev/radio --- */
  	case SAA6588_CMD_POLL:
  		a->poll_mask = 0;
  		if (s->data_available_for_read)
  			a->poll_mask |= EPOLLIN | EPOLLRDNORM;
  		poll_wait(a->instance, &s->read_queue, a->event_list);
  		break;
  
  	default:
  		/* nothing */
  		return -ENOIOCTLCMD;
  	}
  	return 0;
  }
  
  static int saa6588_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *vt)
  {
  	struct saa6588 *s = to_saa6588(sd);
  
  	vt->capability |= V4L2_TUNER_CAP_RDS | V4L2_TUNER_CAP_RDS_BLOCK_IO;
  	if (s->sync)
  		vt->rxsubchans |= V4L2_TUNER_SUB_RDS;
  	return 0;
  }
  
  static int saa6588_s_tuner(struct v4l2_subdev *sd, const struct v4l2_tuner *vt)
  {
  	struct saa6588 *s = to_saa6588(sd);
  
  	saa6588_configure(s);
  	return 0;
  }
  
  /* ----------------------------------------------------------------------- */
  
  static const struct v4l2_subdev_core_ops saa6588_core_ops = {
  	.command = saa6588_command,
  };
  
  static const struct v4l2_subdev_tuner_ops saa6588_tuner_ops = {
  	.g_tuner = saa6588_g_tuner,
  	.s_tuner = saa6588_s_tuner,
  };
  
  static const struct v4l2_subdev_ops saa6588_ops = {
  	.core = &saa6588_core_ops,
  	.tuner = &saa6588_tuner_ops,
  };
  
  /* ---------------------------------------------------------------------- */
  
  static int saa6588_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct saa6588 *s;
  	struct v4l2_subdev *sd;
  
  	v4l_info(client, "saa6588 found @ 0x%x (%s)\n",
  			client->addr << 1, client->adapter->name);
  
  	s = devm_kzalloc(&client->dev, sizeof(*s), GFP_KERNEL);
  	if (s == NULL)
  		return -ENOMEM;
  
  	s->buf_size = bufblocks * 3;
  
  	s->buffer = devm_kzalloc(&client->dev, s->buf_size, GFP_KERNEL);
  	if (s->buffer == NULL)
  		return -ENOMEM;
  	sd = &s->sd;
  	v4l2_i2c_subdev_init(sd, client, &saa6588_ops);
  	spin_lock_init(&s->lock);
  	s->block_count = 0;
  	s->wr_index = 0;
  	s->rd_index = 0;
  	s->last_blocknum = 0xff;
  	init_waitqueue_head(&s->read_queue);
  	s->data_available_for_read = 0;
  
  	saa6588_configure(s);
  
  	/* start polling via eventd */
  	INIT_DELAYED_WORK(&s->work, saa6588_work);
  	schedule_delayed_work(&s->work, 0);
  	return 0;
  }
  
  static int saa6588_remove(struct i2c_client *client)
  {
  	struct v4l2_subdev *sd = i2c_get_clientdata(client);
  	struct saa6588 *s = to_saa6588(sd);
  
  	v4l2_device_unregister_subdev(sd);
  
  	cancel_delayed_work_sync(&s->work);
  
  	return 0;
  }
  
  /* ----------------------------------------------------------------------- */
  
  static const struct i2c_device_id saa6588_id[] = {
  	{ "saa6588", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, saa6588_id);
  
  static struct i2c_driver saa6588_driver = {
  	.driver = {
  		.name	= "saa6588",
  	},
  	.probe		= saa6588_probe,
  	.remove		= saa6588_remove,
  	.id_table	= saa6588_id,
  };
  
  module_i2c_driver(saa6588_driver);
  