drivers/media/video/saa6588.c - arm/linux-arm64-legacy - Git at Google

 /*
     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 "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_PARM(debug, "i");
 MODULE_PARM_DESC(debug, "enable debug messages");
 MODULE_PARM(xtal, "i");
 MODULE_PARM_DESC(xtal, "select oscillator frequency (0..3), default 0");
 MODULE_PARM(rbds, "i");
 MODULE_PARM_DESC(rbds, "select mode, 0=RDS, 1=RBDS, default 0");
 MODULE_PARM(plvl, "i");
 MODULE_PARM_DESC(plvl, "select pause level (0..3), default 0");
 MODULE_PARM(bufblocks, "i");
 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)
 		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(void *data)
 {
 	struct saa6588 *s = (struct saa6588 *)data;

 	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;
 	}
 	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, s);
 	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)
 {
 #ifdef I2C_CLASS_TV_ANALOG
 	if (adap->class & I2C_CLASS_TV_ANALOG)
 		return i2c_probe(adap, &addr_data, saa6588_attach);
 #else
 	switch (adap->id) {
 	case I2C_HW_B_BT848:
 	case I2C_HW_B_RIVA:
 	case I2C_HW_SAA7134:
 		return i2c_probe(adap, &addr_data, saa6588_attach);
 		break;
 	}
 #endif
 	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 = {
 	.owner = THIS_MODULE,
 	.name = "i2c saa6588 driver",
 	.id = -1,		/* FIXME */
 	.flags = I2C_DF_NOTIFY,
 	.attach_adapter = saa6588_probe,
 	.detach_client = saa6588_detach,
 	.command = saa6588_command,
 };

 static struct i2c_client client_template = {
 	.name = "saa6588",
 	.flags = I2C_CLIENT_ALLOW_USE,
 	.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:
  */
	/*
	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 "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_PARM(debug, "i");
	MODULE_PARM_DESC(debug, "enable debug messages");
	MODULE_PARM(xtal, "i");
	MODULE_PARM_DESC(xtal, "select oscillator frequency (0..3), default 0");
	MODULE_PARM(rbds, "i");
	MODULE_PARM_DESC(rbds, "select mode, 0=RDS, 1=RBDS, default 0");
	MODULE_PARM(plvl, "i");
	MODULE_PARM_DESC(plvl, "select pause level (0..3), default 0");
	MODULE_PARM(bufblocks, "i");
	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)
	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(void *data)
	{
	struct saa6588 s = (struct saa6588 )data;

	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;
	}
	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, s);
	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)
	{
	#ifdef I2C_CLASS_TV_ANALOG
	if (adap->class & I2C_CLASS_TV_ANALOG)
	return i2c_probe(adap, &addr_data, saa6588_attach);
	#else
	switch (adap->id) {
	case I2C_HW_B_BT848:
	case I2C_HW_B_RIVA:
	case I2C_HW_SAA7134:
	return i2c_probe(adap, &addr_data, saa6588_attach);
	break;
	}
	#endif
	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 = {
	.owner = THIS_MODULE,
	.name = "i2c saa6588 driver",
	.id = -1, /* FIXME */
	.flags = I2C_DF_NOTIFY,
	.attach_adapter = saa6588_probe,
	.detach_client = saa6588_detach,
	.command = saa6588_command,
	};

	static struct i2c_client client_template = {
	.name = "saa6588",
	.flags = I2C_CLIENT_ALLOW_USE,
	.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:
	*/