saa6588.c

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/*
    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/videodev2.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/saa6588.h>
#include <media/v4l2-device.h>
#include <media/v4l2-chip-ident.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 <[email protected]>");

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 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 saa6588_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)
{
    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.
     */

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

    /* 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_ioctl(struct v4l2_subdev *sd, unsigned int cmd, void *arg)
{
    struct saa6588 *s = to_saa6588(sd);
    struct saa6588_command *a = arg;

    switch (cmd) {
        /* --- open() for /dev/radio --- */
    case SAA6588_CMD_OPEN:
        a->result = 0;  /* return error if chip doesn't work ??? */
        break;
        /* --- close() for /dev/radio --- */
    case SAA6588_CMD_CLOSE:
        s->data_available_for_read = 1;
        wake_up_interruptible(&s->read_queue);
        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->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 */
        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, struct v4l2_tuner *vt)
{
    struct saa6588 *s = to_saa6588(sd);

    saa6588_configure(s);
    return 0;
}

static int saa6588_g_chip_ident(struct v4l2_subdev *sd, struct v4l2_dbg_chip_ident *chip)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);

    return v4l2_chip_ident_i2c_client(client, chip, V4L2_IDENT_SAA6588, 0);
}

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

static const struct v4l2_subdev_core_ops saa6588_core_ops = {
    .g_chip_ident = saa6588_g_chip_ident,
    .ioctl = saa6588_ioctl,
};

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

    s->buf_size = bufblocks * 3;

    s->buffer = kmalloc(s->buf_size, GFP_KERNEL);
    if (s->buffer == NULL) {
        kfree(s);
        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);

    kfree(s->buffer);
    kfree(s);
    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 = {
        .owner  = THIS_MODULE,
        .name   = "saa6588",
    },
    .probe      = saa6588_probe,
    .remove     = saa6588_remove,
    .id_table   = saa6588_id,
};

module_i2c_driver(saa6588_driver);