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saa6588.c

/*
    Driver for SAA6588 RDS decoder

    (c) 2005 Hans J. Koch

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/


#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/types.h>
#include <linux/videodev.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/wait.h>
#include <asm/uaccess.h>


#include <media/rds.h>

/* Addresses to scan */
static unsigned short normal_i2c[] = {
      0x20 >> 1,
      0x22 >> 1,
      I2C_CLIENT_END,
};

I2C_CLIENT_INSMOD;

/* insmod options */
static unsigned int debug = 0;
static unsigned int xtal = 0;
static unsigned int rbds = 0;
static unsigned int plvl = 0;
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(rbds, int, 0);
MODULE_PARM_DESC(rbds, "select mode, 0=RDS, 1=RBDS, default 0");
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 i2c_client client;
      struct work_struct work;
      struct timer_list timer;
      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;
};

static struct i2c_driver driver;
static struct i2c_client client_template;

/* ---------------------------------------------------------------------- */

/*
 * 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 int block_to_user_buf(struct saa6588 *s, unsigned char __user *user_buf)
{
      int i;

      if (s->rd_index == s->wr_index) {
            if (debug > 2)
                  dprintk(PREFIX "Read: buffer empty.\n");
            return 0;
      }

      if (debug > 2) {
            dprintk(PREFIX "Read: ");
            for (i = s->rd_index; i < s->rd_index + 3; i++)
                  dprintk("0x%02x ", s->buffer[i]);
      }

      if (copy_to_user(user_buf, &s->buffer[s->rd_index], 3))
            return -EFAULT;

      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 1;
}

static void read_from_buf(struct saa6588 *s, struct rds_command *a)
{
      unsigned long flags;

      unsigned char __user *buf_ptr = a->buffer;
      unsigned int i;
      unsigned int rd_blocks;

      a->result = 0;
      if (!a->buffer)
            return;

      while (!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;
            }
      }

      spin_lock_irqsave(&s->lock, flags);
      rd_blocks = a->block_count;
      if (rd_blocks > s->block_count)
            rd_blocks = s->block_count;

      if (!rd_blocks) {
            spin_unlock_irqrestore(&s->lock, flags);
            return;
      }

      for (i = 0; i < rd_blocks; i++) {
            if (block_to_user_buf(s, buf_ptr)) {
                  buf_ptr += 3;
                  a->result++;
            } else
                  break;
      }
      a->result *= 3;
      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)
{
      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(&s->client, &tmpbuf[0], 6)) {
            if (debug > 1)
                  dprintk(PREFIX "read error!\n");
            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: Received Offset. Indicates the offset received
         by the sync system.
         Bits 2-0: Offset Name. Indicates the offset applied to this data.

         SAA6588 byte order is Status-MSB-LSB, so we have to swap the
         first and the last of the 3 bytes block.
       */

      tmp = tmpbuf[2];
      tmpbuf[2] = tmpbuf[0];
      tmpbuf[0] = tmp;

      tmp = blocknum;
      tmp |= blocknum << 3;   /* Received offset == Offset Name (OK ?) */
      if ((tmpbuf[2] & 0x03) == 0x03)
            tmp |= 0x80;      /* uncorrectable error */
      else if ((tmpbuf[2] & 0x03) != 0x00)
            tmp |= 0x40;      /* 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_timer(unsigned long data)
{
      struct saa6588 *s = (struct saa6588 *)data;

      schedule_work(&s->work);
}

static void saa6588_work(struct work_struct *work)
{
      struct saa6588 *s = container_of(work, struct saa6588, work);

      saa6588_i2c_poll(s);
      mod_timer(&s->timer, jiffies + msecs_to_jiffies(20));
}

static int saa6588_configure(struct saa6588 *s)
{
      unsigned char buf[3];
      int rc;

      buf[0] = cSyncRestart;
      if (rbds)
            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]);

      if (3 != (rc = i2c_master_send(&s->client, buf, 3)))
            printk(PREFIX "i2c i/o error: rc == %d (should be 3)\n", rc);

      return 0;
}

/* ---------------------------------------------------------------------- */

static int saa6588_attach(struct i2c_adapter *adap, int addr, int kind)
{
      struct saa6588 *s;
      client_template.adapter = adap;
      client_template.addr = addr;

      printk(PREFIX "chip found @ 0x%x\n", addr << 1);

      if (NULL == (s = kmalloc(sizeof(*s), GFP_KERNEL)))
            return -ENOMEM;

      s->buf_size = bufblocks * 3;

      if (NULL == (s->buffer = kmalloc(s->buf_size, GFP_KERNEL))) {
            kfree(s);
            return -ENOMEM;
      }
      spin_lock_init(&s->lock);
      s->client = client_template;
      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;
      i2c_set_clientdata(&s->client, s);
      i2c_attach_client(&s->client);

      saa6588_configure(s);

      /* start polling via eventd */
      INIT_WORK(&s->work, saa6588_work);
      init_timer(&s->timer);
      s->timer.function = saa6588_timer;
      s->timer.data = (unsigned long)s;
      schedule_work(&s->work);
      return 0;
}

static int saa6588_probe(struct i2c_adapter *adap)
{
      if (adap->class & I2C_CLASS_TV_ANALOG)
            return i2c_probe(adap, &addr_data, saa6588_attach);
      return 0;
}

static int saa6588_detach(struct i2c_client *client)
{
      struct saa6588 *s = i2c_get_clientdata(client);

      del_timer_sync(&s->timer);
      flush_scheduled_work();

      i2c_detach_client(client);
      kfree(s->buffer);
      kfree(s);
      return 0;
}

static int saa6588_command(struct i2c_client *client, unsigned int cmd,
                                          void *arg)
{
      struct saa6588 *s = i2c_get_clientdata(client);
      struct rds_command *a = (struct rds_command *)arg;

      switch (cmd) {
            /* --- open() for /dev/radio --- */
      case RDS_CMD_OPEN:
            a->result = 0;    /* return error if chip doesn't work ??? */
            break;
            /* --- close() for /dev/radio --- */
      case RDS_CMD_CLOSE:
            s->data_available_for_read = 1;
            wake_up_interruptible(&s->read_queue);
            a->result = 0;
            break;
            /* --- read() for /dev/radio --- */
      case RDS_CMD_READ:
            read_from_buf(s, a);
            break;
            /* --- poll() for /dev/radio --- */
      case RDS_CMD_POLL:
            a->result = 0;
            if (s->data_available_for_read) {
                  a->result |= POLLIN | POLLRDNORM;
            }
            poll_wait(a->instance, &s->read_queue, a->event_list);
            break;

      default:
            /* nothing */
            break;
      }
      return 0;
}

/* ----------------------------------------------------------------------- */

static struct i2c_driver driver = {
      .driver = {
            .name = "saa6588",
      },
      .id = -1,         /* FIXME */
      .attach_adapter = saa6588_probe,
      .detach_client = saa6588_detach,
      .command = saa6588_command,
};

static struct i2c_client client_template = {
      .name = "saa6588",
      .driver = &driver,
};

static int __init saa6588_init_module(void)
{
      return i2c_add_driver(&driver);
}

static void __exit saa6588_cleanup_module(void)
{
      i2c_del_driver(&driver);
}

module_init(saa6588_init_module);
module_exit(saa6588_cleanup_module);

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-basic-offset: 8
 * End:
 */

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