// SPDX-License-Identifier: GPL-2.0-only
/* radio-cadet.c - A video4linux driver for the ADS Cadet AM/FM Radio Card
 *
 * by Fred Gleason <fredg@wava.com>
 * Version 0.3.3
 *
 * (Loosely) based on code for the Aztech radio card by
 *
 * Russell Kroll    (rkroll@exploits.org)
 * Quay Ly
 * Donald Song
 * Jason Lewis      (jlewis@twilight.vtc.vsc.edu)
 * Scott McGrath    (smcgrath@twilight.vtc.vsc.edu)
 * William McGrath  (wmcgrath@twilight.vtc.vsc.edu)
 *
 * History:
 * 2000-04-29   Russell Kroll <rkroll@exploits.org>
 *              Added ISAPnP detection for Linux 2.3/2.4
 *
 * 2001-01-10   Russell Kroll <rkroll@exploits.org>
 *              Removed dead CONFIG_RADIO_CADET_PORT code
 *              PnP detection on load is now default (no args necessary)
 *
 * 2002-01-17   Adam Belay <ambx1@neo.rr.com>
 *              Updated to latest pnp code
 *
 * 2003-01-31   Alan Cox <alan@lxorguk.ukuu.org.uk>
 *              Cleaned up locking, delay code, general odds and ends
 *
 * 2006-07-30   Hans J. Koch <koch@hjk-az.de>
 *              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 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 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;

        freq = clamp(freq, bands[dev->is_fm_band].rangelow,
                           bands[dev->is_fm_band].rangehigh);
        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 bool cadet_has_rds_data(struct cadet *dev)
{
        bool result;

        mutex_lock(&dev->lock);
        result = dev->rdsin != dev->rdsout;
        mutex_unlock(&dev->lock);
        return result;
}


static void cadet_handler(struct timer_list *t)
{
        struct cadet *dev = from_timer(dev, t, readtimer);

        /* Service the RDS fifo */
        if (mutex_trylock(&dev->lock)) {
                outb(0x3, dev->io);       /* Select RDS Decoder Control */
                if ((inb(dev->io + 1) & 0x20) != 0)
                        pr_err("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)
                                dev->rdsin++;
                }
                mutex_unlock(&dev->lock);
        }

        /*
         * Service pending read
         */
        if (cadet_has_rds_data(dev))
                wake_up_interruptible(&dev->read_queue);

        /*
         * Clean up and exit
         */
        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 */
        timer_setup(&dev->readtimer, cadet_handler, 0);
        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);
        mutex_unlock(&dev->lock);

        if (!cadet_has_rds_data(dev) && (file->f_flags & O_NONBLOCK))
                return -EWOULDBLOCK;
        i = wait_event_interruptible(dev->read_queue, cadet_has_rds_data(dev));
        if (i)
                return i;

        mutex_lock(&dev->lock);
        while (i < count && dev->rdsin != dev->rdsout)
                readbuf[i++] = dev->rdsbuf[dev->rdsout++];
        mutex_unlock(&dev->lock);

        if (i && copy_to_user(data, readbuf, i))
                return -EFAULT;
        return i;
}


static int vidioc_querycap(struct file *file, void *priv,
                                struct v4l2_capability *v)
{
        strscpy(v->driver, "ADS Cadet", sizeof(v->driver));
        strscpy(v->card, "ADS Cadet", sizeof(v->card));
        strscpy(v->bus_info, "ISA:radio-cadet", sizeof(v->bus_info));
        return 0;
}

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;
        strscpy(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,
                                const 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,
                                const 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;
        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 __poll_t cadet_poll(struct file *file, struct poll_table_struct *wait)
{
        struct cadet *dev = video_drvdata(file);
        __poll_t req_events = poll_requested_events(wait);
        __poll_t res = v4l2_ctrl_poll(file, wait);

        poll_wait(file, &dev->read_queue, wait);
        if (dev->rdsstat == 0 && (req_events & (EPOLLIN | EPOLLRDNORM))) {
                mutex_lock(&dev->lock);
                if (dev->rdsstat == 0)
                        cadet_start_rds(dev);
                mutex_unlock(&dev->lock);
        }
        if (cadet_has_rds_data(dev))
                res |= EPOLLIN | EPOLLRDNORM;
        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 const 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;

        strscpy(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);
        strscpy(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;
        dev->vdev.device_caps = V4L2_CAP_TUNER | V4L2_CAP_RADIO |
                                V4L2_CAP_READWRITE | V4L2_CAP_RDS_CAPTURE;
        video_set_drvdata(&dev->vdev, dev);

        res = video_register_device(&dev->vdev, VFL_TYPE_RADIO, radio_nr);
        if (res < 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);