radio-cadet.c

Go to the documentation of this file.

/* radio-cadet.c - A video4linux driver for the ADS Cadet AM/FM Radio Card
 *
 * by Fred Gleason <[email protected]>
 * Version 0.3.3
 *
 * (Loosely) based on code for the Aztech radio card by
 *
 * Russell Kroll    ([email protected])
 * Quay Ly
 * Donald Song
 * Jason Lewis      ([email protected])
 * Scott McGrath    ([email protected])
 * William McGrath  ([email protected])
 *
 * History:
 * 2000-04-29   Russell Kroll <[email protected]>
 *      Added ISAPnP detection for Linux 2.3/2.4
 *
 * 2001-01-10   Russell Kroll <[email protected]>
 *      Removed dead CONFIG_RADIO_CADET_PORT code
 *      PnP detection on load is now default (no args necessary)
 *
 * 2002-01-17   Adam Belay <[email protected]>
 *      Updated to latest pnp code
 *
 * 2003-01-31   Alan Cox <[email protected]>
 *      Cleaned up locking, delay code, general odds and ends
 *
 * 2006-07-30   Hans J. Koch <[email protected]>
 *      Changed API to V4L2
 */

#include <linux/module.h>   /* Modules          */
#include <linux/init.h>     /* Initdata         */
#include <linux/ioport.h>   /* request_region       */
#include <linux/delay.h>    /* udelay           */
#include <linux/videodev2.h>    /* V4L2 API defs        */
#include <linux/param.h>
#include <linux/pnp.h>
#include <linux/sched.h>
#include <linux/io.h>       /* outb, outb_p         */
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>

MODULE_AUTHOR("Fred Gleason, Russell Kroll, Quay Lu, Donald Song, Jason Lewis, Scott McGrath, William McGrath");
MODULE_DESCRIPTION("A driver for the ADS Cadet AM/FM/RDS radio card.");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.3.4");

static int io = -1;     /* default to isapnp activation */
static int radio_nr = -1;

module_param(io, int, 0);
MODULE_PARM_DESC(io, "I/O address of Cadet card (0x330,0x332,0x334,0x336,0x338,0x33a,0x33c,0x33e)");
module_param(radio_nr, int, 0);

#define RDS_BUFFER 256
#define RDS_RX_FLAG 1
#define MBS_RX_FLAG 2

struct cadet {
    struct v4l2_device v4l2_dev;
    struct video_device vdev;
    struct v4l2_ctrl_handler ctrl_handler;
    int io;
    bool is_fm_band;
    u32 curfreq;
    int tunestat;
    int sigstrength;
    wait_queue_head_t read_queue;
    struct timer_list readtimer;
    u8 rdsin, rdsout, rdsstat;
    unsigned char rdsbuf[RDS_BUFFER];
    struct mutex lock;
    int reading;
};

static struct cadet cadet_card;

/*
 * Signal Strength Threshold Values
 * The V4L API spec does not define any particular unit for the signal
 * strength value.  These values are in microvolts of RF at the tuner's input.
 */
static u16 sigtable[2][4] = {
    { 1835, 2621,  4128, 65535 },
    { 2185, 4369, 13107, 65535 },
};


static int cadet_getstereo(struct cadet *dev)
{
    int ret = V4L2_TUNER_SUB_MONO;

    if (!dev->is_fm_band)   /* Only FM has stereo capability! */
        return V4L2_TUNER_SUB_MONO;

    outb(7, dev->io);          /* Select tuner control */
    if ((inb(dev->io + 1) & 0x40) == 0)
        ret = V4L2_TUNER_SUB_STEREO;
    return ret;
}

static unsigned cadet_gettune(struct cadet *dev)
{
    int curvol, i;
    unsigned fifo = 0;

    /*
     * Prepare for read
     */

    outb(7, dev->io);       /* Select tuner control */
    curvol = inb(dev->io + 1); /* Save current volume/mute setting */
    outb(0x00, dev->io + 1);  /* Ensure WRITE-ENABLE is LOW */
    dev->tunestat = 0xffff;

    /*
     * Read the shift register
     */
    for (i = 0; i < 25; i++) {
        fifo = (fifo << 1) | ((inb(dev->io + 1) >> 7) & 0x01);
        if (i < 24) {
            outb(0x01, dev->io + 1);
            dev->tunestat &= inb(dev->io + 1);
            outb(0x00, dev->io + 1);
        }
    }

    /*
     * Restore volume/mute setting
     */
    outb(curvol, dev->io + 1);
    return fifo;
}

static unsigned cadet_getfreq(struct cadet *dev)
{
    int i;
    unsigned freq = 0, test, fifo = 0;

    /*
     * Read current tuning
     */
    fifo = cadet_gettune(dev);

    /*
     * Convert to actual frequency
     */
    if (!dev->is_fm_band)    /* AM */
        return ((fifo & 0x7fff) - 450) * 16;

    test = 12500;
    for (i = 0; i < 14; i++) {
        if ((fifo & 0x01) != 0)
            freq += test;
        test = test << 1;
        fifo = fifo >> 1;
    }
    freq -= 10700000;           /* IF frequency is 10.7 MHz */
    freq = (freq * 16) / 1000;   /* Make it 1/16 kHz */
    return freq;
}

static void cadet_settune(struct cadet *dev, unsigned fifo)
{
    int i;
    unsigned test;

    outb(7, dev->io);                /* Select tuner control */
    /*
     * Write the shift register
     */
    test = 0;
    test = (fifo >> 23) & 0x02;      /* Align data for SDO */
    test |= 0x1c;                /* SDM=1, SWE=1, SEN=1, SCK=0 */
    outb(7, dev->io);                /* Select tuner control */
    outb(test, dev->io + 1);           /* Initialize for write */
    for (i = 0; i < 25; i++) {
        test |= 0x01;              /* Toggle SCK High */
        outb(test, dev->io + 1);
        test &= 0xfe;              /* Toggle SCK Low */
        outb(test, dev->io + 1);
        fifo = fifo << 1;            /* Prepare the next bit */
        test = 0x1c | ((fifo >> 23) & 0x02);
        outb(test, dev->io + 1);
    }
}

static void cadet_setfreq(struct cadet *dev, unsigned freq)
{
    unsigned fifo;
    int i, j, test;
    int curvol;

    dev->curfreq = freq;
    /*
     * Formulate a fifo command
     */
    fifo = 0;
    if (dev->is_fm_band) {    /* FM */
        test = 102400;
        freq = freq / 16;       /* Make it kHz */
        freq += 10700;               /* IF is 10700 kHz */
        for (i = 0; i < 14; i++) {
            fifo = fifo << 1;
            if (freq >= test) {
                fifo |= 0x01;
                freq -= test;
            }
            test = test >> 1;
        }
    } else {    /* AM */
        fifo = (freq / 16) + 450;   /* Make it kHz */
        fifo |= 0x100000;       /* Select AM Band */
    }

    /*
     * Save current volume/mute setting
     */

    outb(7, dev->io);                /* Select tuner control */
    curvol = inb(dev->io + 1);

    /*
     * Tune the card
     */
    for (j = 3; j > -1; j--) {
        cadet_settune(dev, fifo | (j << 16));

        outb(7, dev->io);         /* Select tuner control */
        outb(curvol, dev->io + 1);

        msleep(100);

        cadet_gettune(dev);
        if ((dev->tunestat & 0x40) == 0) {   /* Tuned */
            dev->sigstrength = sigtable[dev->is_fm_band][j];
            goto reset_rds;
        }
    }
    dev->sigstrength = 0;
reset_rds:
    outb(3, dev->io);
    outb(inb(dev->io + 1) & 0x7f, dev->io + 1);
}


static void cadet_handler(unsigned long data)
{
    struct cadet *dev = (void *)data;

    /* Service the RDS fifo */
    if (mutex_trylock(&dev->lock)) {
        outb(0x3, dev->io);       /* Select RDS Decoder Control */
        if ((inb(dev->io + 1) & 0x20) != 0)
            printk(KERN_CRIT "cadet: RDS fifo overflow\n");
        outb(0x80, dev->io);      /* Select RDS fifo */
        while ((inb(dev->io) & 0x80) != 0) {
            dev->rdsbuf[dev->rdsin] = inb(dev->io + 1);
            if (dev->rdsin + 1 == dev->rdsout)
                printk(KERN_WARNING "cadet: RDS buffer overflow\n");
            else
                dev->rdsin++;
        }
        mutex_unlock(&dev->lock);
    }

    /*
     * Service pending read
     */
    if (dev->rdsin != dev->rdsout)
        wake_up_interruptible(&dev->read_queue);

    /*
     * Clean up and exit
     */
    init_timer(&dev->readtimer);
    dev->readtimer.function = cadet_handler;
    dev->readtimer.data = data;
    dev->readtimer.expires = jiffies + msecs_to_jiffies(50);
    add_timer(&dev->readtimer);
}

static void cadet_start_rds(struct cadet *dev)
{
    dev->rdsstat = 1;
    outb(0x80, dev->io);        /* Select RDS fifo */
    init_timer(&dev->readtimer);
    dev->readtimer.function = cadet_handler;
    dev->readtimer.data = (unsigned long)dev;
    dev->readtimer.expires = jiffies + msecs_to_jiffies(50);
    add_timer(&dev->readtimer);
}

static ssize_t cadet_read(struct file *file, char __user *data, size_t count, loff_t *ppos)
{
    struct cadet *dev = video_drvdata(file);
    unsigned char readbuf[RDS_BUFFER];
    int i = 0;

    mutex_lock(&dev->lock);
    if (dev->rdsstat == 0)
        cadet_start_rds(dev);
    if (dev->rdsin == dev->rdsout) {
        if (file->f_flags & O_NONBLOCK) {
            i = -EWOULDBLOCK;
            goto unlock;
        }
        mutex_unlock(&dev->lock);
        interruptible_sleep_on(&dev->read_queue);
        mutex_lock(&dev->lock);
    }
    while (i < count && dev->rdsin != dev->rdsout)
        readbuf[i++] = dev->rdsbuf[dev->rdsout++];

    if (i && copy_to_user(data, readbuf, i))
        i = -EFAULT;
unlock:
    mutex_unlock(&dev->lock);
    return i;
}


static int vidioc_querycap(struct file *file, void *priv,
                struct v4l2_capability *v)
{
    strlcpy(v->driver, "ADS Cadet", sizeof(v->driver));
    strlcpy(v->card, "ADS Cadet", sizeof(v->card));
    strlcpy(v->bus_info, "ISA", sizeof(v->bus_info));
    v->device_caps = V4L2_CAP_TUNER | V4L2_CAP_RADIO |
              V4L2_CAP_READWRITE | V4L2_CAP_RDS_CAPTURE;
    v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
    return 0;
}

static const struct v4l2_frequency_band bands[] = {
    {
        .index = 0,
        .type = V4L2_TUNER_RADIO,
        .capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_FREQ_BANDS,
        .rangelow = 8320,      /* 520 kHz */
        .rangehigh = 26400,    /* 1650 kHz */
        .modulation = V4L2_BAND_MODULATION_AM,
    }, {
        .index = 1,
        .type = V4L2_TUNER_RADIO,
        .capability = V4L2_TUNER_CAP_STEREO | V4L2_TUNER_CAP_RDS |
            V4L2_TUNER_CAP_RDS_BLOCK_IO | V4L2_TUNER_CAP_LOW |
            V4L2_TUNER_CAP_FREQ_BANDS,
        .rangelow = 1400000,   /* 87.5 MHz */
        .rangehigh = 1728000,  /* 108.0 MHz */
        .modulation = V4L2_BAND_MODULATION_FM,
    },
};

static int vidioc_g_tuner(struct file *file, void *priv,
                struct v4l2_tuner *v)
{
    struct cadet *dev = video_drvdata(file);

    if (v->index)
        return -EINVAL;
    v->type = V4L2_TUNER_RADIO;
    strlcpy(v->name, "Radio", sizeof(v->name));
    v->capability = bands[0].capability | bands[1].capability;
    v->rangelow = bands[0].rangelow;       /* 520 kHz (start of AM band) */
    v->rangehigh = bands[1].rangehigh;    /* 108.0 MHz (end of FM band) */
    if (dev->is_fm_band) {
        v->rxsubchans = cadet_getstereo(dev);
        outb(3, dev->io);
        outb(inb(dev->io + 1) & 0x7f, dev->io + 1);
        mdelay(100);
        outb(3, dev->io);
        if (inb(dev->io + 1) & 0x80)
            v->rxsubchans |= V4L2_TUNER_SUB_RDS;
    } else {
        v->rangelow = 8320;      /* 520 kHz */
        v->rangehigh = 26400;    /* 1650 kHz */
        v->rxsubchans = V4L2_TUNER_SUB_MONO;
    }
    v->audmode = V4L2_TUNER_MODE_STEREO;
    v->signal = dev->sigstrength; /* We might need to modify scaling of this */
    return 0;
}

static int vidioc_s_tuner(struct file *file, void *priv,
                struct v4l2_tuner *v)
{
    return v->index ? -EINVAL : 0;
}

static int vidioc_enum_freq_bands(struct file *file, void *priv,
                struct v4l2_frequency_band *band)
{
    if (band->tuner)
        return -EINVAL;
    if (band->index >= ARRAY_SIZE(bands))
        return -EINVAL;
    *band = bands[band->index];
    return 0;
}

static int vidioc_g_frequency(struct file *file, void *priv,
                struct v4l2_frequency *f)
{
    struct cadet *dev = video_drvdata(file);

    if (f->tuner)
        return -EINVAL;
    f->type = V4L2_TUNER_RADIO;
    f->frequency = dev->curfreq;
    return 0;
}


static int vidioc_s_frequency(struct file *file, void *priv,
                struct v4l2_frequency *f)
{
    struct cadet *dev = video_drvdata(file);

    if (f->tuner)
        return -EINVAL;
    dev->is_fm_band =
        f->frequency >= (bands[0].rangehigh + bands[1].rangelow) / 2;
    clamp(f->frequency, bands[dev->is_fm_band].rangelow,
                bands[dev->is_fm_band].rangehigh);
    cadet_setfreq(dev, f->frequency);
    return 0;
}

static int cadet_s_ctrl(struct v4l2_ctrl *ctrl)
{
    struct cadet *dev = container_of(ctrl->handler, struct cadet, ctrl_handler);

    switch (ctrl->id) {
    case V4L2_CID_AUDIO_MUTE:
        outb(7, dev->io);                /* Select tuner control */
        if (ctrl->val)
            outb(0x00, dev->io + 1);
        else
            outb(0x20, dev->io + 1);
        return 0;
    }
    return -EINVAL;
}

static int cadet_open(struct file *file)
{
    struct cadet *dev = video_drvdata(file);
    int err;

    mutex_lock(&dev->lock);
    err = v4l2_fh_open(file);
    if (err)
        goto fail;
    if (v4l2_fh_is_singular_file(file))
        init_waitqueue_head(&dev->read_queue);
fail:
    mutex_unlock(&dev->lock);
    return err;
}

static int cadet_release(struct file *file)
{
    struct cadet *dev = video_drvdata(file);

    mutex_lock(&dev->lock);
    if (v4l2_fh_is_singular_file(file) && dev->rdsstat) {
        del_timer_sync(&dev->readtimer);
        dev->rdsstat = 0;
    }
    v4l2_fh_release(file);
    mutex_unlock(&dev->lock);
    return 0;
}

static unsigned int cadet_poll(struct file *file, struct poll_table_struct *wait)
{
    struct cadet *dev = video_drvdata(file);
    unsigned long req_events = poll_requested_events(wait);
    unsigned int res = v4l2_ctrl_poll(file, wait);

    poll_wait(file, &dev->read_queue, wait);
    if (dev->rdsstat == 0 && (req_events & (POLLIN | POLLRDNORM))) {
        mutex_lock(&dev->lock);
        if (dev->rdsstat == 0)
            cadet_start_rds(dev);
        mutex_unlock(&dev->lock);
    }
    if (dev->rdsin != dev->rdsout)
        res |= POLLIN | POLLRDNORM;
    return res;
}


static const struct v4l2_file_operations cadet_fops = {
    .owner      = THIS_MODULE,
    .open       = cadet_open,
    .release        = cadet_release,
    .read       = cadet_read,
    .unlocked_ioctl = video_ioctl2,
    .poll       = cadet_poll,
};

static const struct v4l2_ioctl_ops cadet_ioctl_ops = {
    .vidioc_querycap    = vidioc_querycap,
    .vidioc_g_tuner     = vidioc_g_tuner,
    .vidioc_s_tuner     = vidioc_s_tuner,
    .vidioc_g_frequency = vidioc_g_frequency,
    .vidioc_s_frequency = vidioc_s_frequency,
    .vidioc_enum_freq_bands = vidioc_enum_freq_bands,
    .vidioc_log_status  = v4l2_ctrl_log_status,
    .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
    .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
};

static const struct v4l2_ctrl_ops cadet_ctrl_ops = {
    .s_ctrl = cadet_s_ctrl,
};

#ifdef CONFIG_PNP

static struct pnp_device_id cadet_pnp_devices[] = {
    /* ADS Cadet AM/FM Radio Card */
    {.id = "MSM0c24", .driver_data = 0},
    {.id = ""}
};

MODULE_DEVICE_TABLE(pnp, cadet_pnp_devices);

static int cadet_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
{
    if (!dev)
        return -ENODEV;
    /* only support one device */
    if (io > 0)
        return -EBUSY;

    if (!pnp_port_valid(dev, 0))
        return -ENODEV;

    io = pnp_port_start(dev, 0);

    printk(KERN_INFO "radio-cadet: PnP reports device at %#x\n", io);

    return io;
}

static struct pnp_driver cadet_pnp_driver = {
    .name       = "radio-cadet",
    .id_table   = cadet_pnp_devices,
    .probe      = cadet_pnp_probe,
    .remove     = NULL,
};

#else
static struct pnp_driver cadet_pnp_driver;
#endif

static void cadet_probe(struct cadet *dev)
{
    static int iovals[8] = { 0x330, 0x332, 0x334, 0x336, 0x338, 0x33a, 0x33c, 0x33e };
    int i;

    for (i = 0; i < 8; i++) {
        dev->io = iovals[i];
        if (request_region(dev->io, 2, "cadet-probe")) {
            cadet_setfreq(dev, bands[1].rangelow);
            if (cadet_getfreq(dev) == bands[1].rangelow) {
                release_region(dev->io, 2);
                return;
            }
            release_region(dev->io, 2);
        }
    }
    dev->io = -1;
}

/*
 * io should only be set if the user has used something like
 * isapnp (the userspace program) to initialize this card for us
 */

static int __init cadet_init(void)
{
    struct cadet *dev = &cadet_card;
    struct v4l2_device *v4l2_dev = &dev->v4l2_dev;
    struct v4l2_ctrl_handler *hdl;
    int res = -ENODEV;

    strlcpy(v4l2_dev->name, "cadet", sizeof(v4l2_dev->name));
    mutex_init(&dev->lock);

    /* If a probe was requested then probe ISAPnP first (safest) */
    if (io < 0)
        pnp_register_driver(&cadet_pnp_driver);
    dev->io = io;

    /* If that fails then probe unsafely if probe is requested */
    if (dev->io < 0)
        cadet_probe(dev);

    /* Else we bail out */
    if (dev->io < 0) {
#ifdef MODULE
        v4l2_err(v4l2_dev, "you must set an I/O address with io=0x330, 0x332, 0x334,\n");
        v4l2_err(v4l2_dev, "0x336, 0x338, 0x33a, 0x33c or 0x33e\n");
#endif
        goto fail;
    }
    if (!request_region(dev->io, 2, "cadet"))
        goto fail;

    res = v4l2_device_register(NULL, v4l2_dev);
    if (res < 0) {
        release_region(dev->io, 2);
        v4l2_err(v4l2_dev, "could not register v4l2_device\n");
        goto fail;
    }

    hdl = &dev->ctrl_handler;
    v4l2_ctrl_handler_init(hdl, 2);
    v4l2_ctrl_new_std(hdl, &cadet_ctrl_ops,
            V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
    v4l2_dev->ctrl_handler = hdl;
    if (hdl->error) {
        res = hdl->error;
        v4l2_err(v4l2_dev, "Could not register controls\n");
        goto err_hdl;
    }

    dev->is_fm_band = true;
    dev->curfreq = bands[dev->is_fm_band].rangelow;
    cadet_setfreq(dev, dev->curfreq);
    strlcpy(dev->vdev.name, v4l2_dev->name, sizeof(dev->vdev.name));
    dev->vdev.v4l2_dev = v4l2_dev;
    dev->vdev.fops = &cadet_fops;
    dev->vdev.ioctl_ops = &cadet_ioctl_ops;
    dev->vdev.release = video_device_release_empty;
    dev->vdev.lock = &dev->lock;
    set_bit(V4L2_FL_USE_FH_PRIO, &dev->vdev.flags);
    video_set_drvdata(&dev->vdev, dev);

    if (video_register_device(&dev->vdev, VFL_TYPE_RADIO, radio_nr) < 0)
        goto err_hdl;
    v4l2_info(v4l2_dev, "ADS Cadet Radio Card at 0x%x\n", dev->io);
    return 0;
err_hdl:
    v4l2_ctrl_handler_free(hdl);
    v4l2_device_unregister(v4l2_dev);
    release_region(dev->io, 2);
fail:
    pnp_unregister_driver(&cadet_pnp_driver);
    return res;
}

static void __exit cadet_exit(void)
{
    struct cadet *dev = &cadet_card;

    video_unregister_device(&dev->vdev);
    v4l2_ctrl_handler_free(&dev->ctrl_handler);
    v4l2_device_unregister(&dev->v4l2_dev);
    outb(7, dev->io);   /* Mute */
    outb(0x00, dev->io + 1);
    release_region(dev->io, 2);
    pnp_unregister_driver(&cadet_pnp_driver);
}

module_init(cadet_init);
module_exit(cadet_exit);