/* zoltrix radio plus driver for Linux radio support
 * (c) 1998 C. van Schaik <carl@leg.uct.ac.za>
 *
 * BUGS
 *  Due to the inconsistency in reading from the signal flags
 *  it is difficult to get an accurate tuned signal.
 *
 *  It seems that the card is not linear to 0 volume. It cuts off
 *  at a low volume, and it is not possible (at least I have not found)
 *  to get fine volume control over the low volume range.
 *
 *  Some code derived from code by Romolo Manfredini
 *				   romolo@bicnet.it
 *
 * 1999-05-06 - (C. van Schaik)
 *	      - Make signal strength and stereo scans
 *		kinder to cpu while in delay
 * 1999-01-05 - (C. van Schaik)
 *	      - Changed tuning to 1/160Mhz accuracy
 *	      - Added stereo support
 *		(card defaults to stereo)
 *		(can explicitly force mono on the card)
 *		(can detect if station is in stereo)
 *	      - Added unmute function
 *	      - Reworked ioctl functions
 * 2002-07-15 - Fix Stereo typo
 *
 * 2006-07-24 - Converted to V4L2 API
 *		by Mauro Carvalho Chehab <mchehab@infradead.org>
 */

#include <linux/module.h>	/* Modules                        */
#include <linux/init.h>		/* Initdata                       */
#include <linux/ioport.h>	/* request_region		  */
#include <linux/delay.h>	/* udelay, msleep                 */
#include <linux/videodev2.h>	/* kernel radio structs           */
#include <linux/mutex.h>
#include <linux/version.h>      /* for KERNEL_VERSION MACRO     */
#include <linux/io.h>		/* outb, outb_p                   */
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>

MODULE_AUTHOR("C.van Schaik");
MODULE_DESCRIPTION("A driver for the Zoltrix Radio Plus.");
MODULE_LICENSE("GPL");

#ifndef CONFIG_RADIO_ZOLTRIX_PORT
#define CONFIG_RADIO_ZOLTRIX_PORT -1
#endif

static int io = CONFIG_RADIO_ZOLTRIX_PORT;
static int radio_nr = -1;

module_param(io, int, 0);
MODULE_PARM_DESC(io, "I/O address of the Zoltrix Radio Plus (0x20c or 0x30c)");
module_param(radio_nr, int, 0);

#define RADIO_VERSION KERNEL_VERSION(0, 0, 2)

struct zoltrix {
	struct v4l2_device v4l2_dev;
	struct video_device vdev;
	int io;
	int curvol;
	unsigned long curfreq;
	int muted;
	unsigned int stereo;
	struct mutex lock;
};

static struct zoltrix zoltrix_card;

static int zol_setvol(struct zoltrix *zol, int vol)
{
	zol->curvol = vol;
	if (zol->muted)
		return 0;

	mutex_lock(&zol->lock);
	if (vol == 0) {
		outb(0, zol->io);
		outb(0, zol->io);
		inb(zol->io + 3);    /* Zoltrix needs to be read to confirm */
		mutex_unlock(&zol->lock);
		return 0;
	}

	outb(zol->curvol-1, zol->io);
	msleep(10);
	inb(zol->io + 2);
	mutex_unlock(&zol->lock);
	return 0;
}

static void zol_mute(struct zoltrix *zol)
{
	zol->muted = 1;
	mutex_lock(&zol->lock);
	outb(0, zol->io);
	outb(0, zol->io);
	inb(zol->io + 3);            /* Zoltrix needs to be read to confirm */
	mutex_unlock(&zol->lock);
}

static void zol_unmute(struct zoltrix *zol)
{
	zol->muted = 0;
	zol_setvol(zol, zol->curvol);
}

static int zol_setfreq(struct zoltrix *zol, unsigned long freq)
{
	/* tunes the radio to the desired frequency */
	struct v4l2_device *v4l2_dev = &zol->v4l2_dev;
	unsigned long long bitmask, f, m;
	unsigned int stereo = zol->stereo;
	int i;

	if (freq == 0) {
		v4l2_warn(v4l2_dev, "cannot set a frequency of 0.\n");
		return -EINVAL;
	}

	m = (freq / 160 - 8800) * 2;
	f = (unsigned long long)m + 0x4d1c;

	bitmask = 0xc480402c10080000ull;
	i = 45;

	mutex_lock(&zol->lock);

	zol->curfreq = freq;

	outb(0, zol->io);
	outb(0, zol->io);
	inb(zol->io + 3);            /* Zoltrix needs to be read to confirm */

	outb(0x40, zol->io);
	outb(0xc0, zol->io);

	bitmask = (bitmask ^ ((f & 0xff) << 47) ^ ((f & 0xff00) << 30) ^ (stereo << 31));
	while (i--) {
		if ((bitmask & 0x8000000000000000ull) != 0) {
			outb(0x80, zol->io);
			udelay(50);
			outb(0x00, zol->io);
			udelay(50);
			outb(0x80, zol->io);
			udelay(50);
		} else {
			outb(0xc0, zol->io);
			udelay(50);
			outb(0x40, zol->io);
			udelay(50);
			outb(0xc0, zol->io);
			udelay(50);
		}
		bitmask *= 2;
	}
	/* termination sequence */
	outb(0x80, zol->io);
	outb(0xc0, zol->io);
	outb(0x40, zol->io);
	udelay(1000);
	inb(zol->io + 2);

	udelay(1000);

	if (zol->muted) {
		outb(0, zol->io);
		outb(0, zol->io);
		inb(zol->io + 3);
		udelay(1000);
	}

	mutex_unlock(&zol->lock);

	if (!zol->muted)
		zol_setvol(zol, zol->curvol);
	return 0;
}

/* Get signal strength */
static int zol_getsigstr(struct zoltrix *zol)
{
	int a, b;

	mutex_lock(&zol->lock);
	outb(0x00, zol->io);         /* This stuff I found to do nothing */
	outb(zol->curvol, zol->io);
	msleep(20);

	a = inb(zol->io);
	msleep(10);
	b = inb(zol->io);

	mutex_unlock(&zol->lock);

	if (a != b)
		return 0;

	/* I found this out by playing with a binary scanner on the card io */
	return a == 0xcf || a == 0xdf || a == 0xef;
}

static int zol_is_stereo(struct zoltrix *zol)
{
	int x1, x2;

	mutex_lock(&zol->lock);

	outb(0x00, zol->io);
	outb(zol->curvol, zol->io);
	msleep(20);

	x1 = inb(zol->io);
	msleep(10);
	x2 = inb(zol->io);

	mutex_unlock(&zol->lock);

	return x1 == x2 && x1 == 0xcf;
}

static int vidioc_querycap(struct file *file, void  *priv,
					struct v4l2_capability *v)
{
	strlcpy(v->driver, "radio-zoltrix", sizeof(v->driver));
	strlcpy(v->card, "Zoltrix Radio", sizeof(v->card));
	strlcpy(v->bus_info, "ISA", sizeof(v->bus_info));
	v->version = RADIO_VERSION;
	v->capabilities = V4L2_CAP_TUNER | V4L2_CAP_RADIO;
	return 0;
}

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

	if (v->index > 0)
		return -EINVAL;

	strlcpy(v->name, "FM", sizeof(v->name));
	v->type = V4L2_TUNER_RADIO;
	v->rangelow = 88 * 16000;
	v->rangehigh = 108 * 16000;
	v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
	v->capability = V4L2_TUNER_CAP_LOW;
	if (zol_is_stereo(zol))
		v->audmode = V4L2_TUNER_MODE_STEREO;
	else
		v->audmode = V4L2_TUNER_MODE_MONO;
	v->signal = 0xFFFF * zol_getsigstr(zol);
	return 0;
}

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

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

	if (zol_setfreq(zol, f->frequency) != 0)
		return -EINVAL;
	return 0;
}

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

	f->type = V4L2_TUNER_RADIO;
	f->frequency = zol->curfreq;
	return 0;
}

static int vidioc_queryctrl(struct file *file, void *priv,
					struct v4l2_queryctrl *qc)
{
	switch (qc->id) {
	case V4L2_CID_AUDIO_MUTE:
		return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
	case V4L2_CID_AUDIO_VOLUME:
		return v4l2_ctrl_query_fill(qc, 0, 65535, 4096, 65535);
	}
	return -EINVAL;
}

static int vidioc_g_ctrl(struct file *file, void *priv,
				struct v4l2_control *ctrl)
{
	struct zoltrix *zol = video_drvdata(file);

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
		ctrl->value = zol->muted;
		return 0;
	case V4L2_CID_AUDIO_VOLUME:
		ctrl->value = zol->curvol * 4096;
		return 0;
	}
	return -EINVAL;
}

static int vidioc_s_ctrl(struct file *file, void *priv,
				struct v4l2_control *ctrl)
{
	struct zoltrix *zol = video_drvdata(file);

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
		if (ctrl->value)
			zol_mute(zol);
		else {
			zol_unmute(zol);
			zol_setvol(zol, zol->curvol);
		}
		return 0;
	case V4L2_CID_AUDIO_VOLUME:
		zol_setvol(zol, ctrl->value / 4096);
		return 0;
	}
	zol->stereo = 1;
	if (zol_setfreq(zol, zol->curfreq) != 0)
		return -EINVAL;
#if 0
/* FIXME: Implement stereo/mono switch on V4L2 */
	if (v->mode & VIDEO_SOUND_STEREO) {
		zol->stereo = 1;
		zol_setfreq(zol, zol->curfreq);
	}
	if (v->mode & VIDEO_SOUND_MONO) {
		zol->stereo = 0;
		zol_setfreq(zol, zol->curfreq);
	}
#endif
	return -EINVAL;
}

static int vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
{
	*i = 0;
	return 0;
}

static int vidioc_s_input(struct file *filp, void *priv, unsigned int i)
{
	return i ? -EINVAL : 0;
}

static int vidioc_g_audio(struct file *file, void *priv,
					struct v4l2_audio *a)
{
	a->index = 0;
	strlcpy(a->name, "Radio", sizeof(a->name));
	a->capability = V4L2_AUDCAP_STEREO;
	return 0;
}

static int vidioc_s_audio(struct file *file, void *priv,
					struct v4l2_audio *a)
{
	return a->index ? -EINVAL : 0;
}

static const struct v4l2_file_operations zoltrix_fops =
{
	.owner		= THIS_MODULE,
	.ioctl		= video_ioctl2,
};

static const struct v4l2_ioctl_ops zoltrix_ioctl_ops = {
	.vidioc_querycap    = vidioc_querycap,
	.vidioc_g_tuner     = vidioc_g_tuner,
	.vidioc_s_tuner     = vidioc_s_tuner,
	.vidioc_g_audio     = vidioc_g_audio,
	.vidioc_s_audio     = vidioc_s_audio,
	.vidioc_g_input     = vidioc_g_input,
	.vidioc_s_input     = vidioc_s_input,
	.vidioc_g_frequency = vidioc_g_frequency,
	.vidioc_s_frequency = vidioc_s_frequency,
	.vidioc_queryctrl   = vidioc_queryctrl,
	.vidioc_g_ctrl      = vidioc_g_ctrl,
	.vidioc_s_ctrl      = vidioc_s_ctrl,
};

static int __init zoltrix_init(void)
{
	struct zoltrix *zol = &zoltrix_card;
	struct v4l2_device *v4l2_dev = &zol->v4l2_dev;
	int res;

	strlcpy(v4l2_dev->name, "zoltrix", sizeof(v4l2_dev->name));
	zol->io = io;
	if (zol->io == -1) {
		v4l2_err(v4l2_dev, "You must set an I/O address with io=0x20c or 0x30c\n");
		return -EINVAL;
	}
	if (zol->io != 0x20c && zol->io != 0x30c) {
		v4l2_err(v4l2_dev, "invalid port, try 0x20c or 0x30c\n");
		return -ENXIO;
	}

	if (!request_region(zol->io, 2, "zoltrix")) {
		v4l2_err(v4l2_dev, "port 0x%x already in use\n", zol->io);
		return -EBUSY;
	}

	res = v4l2_device_register(NULL, v4l2_dev);
	if (res < 0) {
		release_region(zol->io, 2);
		v4l2_err(v4l2_dev, "Could not register v4l2_device\n");
		return res;
	}

	strlcpy(zol->vdev.name, v4l2_dev->name, sizeof(zol->vdev.name));
	zol->vdev.v4l2_dev = v4l2_dev;
	zol->vdev.fops = &zoltrix_fops;
	zol->vdev.ioctl_ops = &zoltrix_ioctl_ops;
	zol->vdev.release = video_device_release_empty;
	video_set_drvdata(&zol->vdev, zol);

	if (video_register_device(&zol->vdev, VFL_TYPE_RADIO, radio_nr) < 0) {
		v4l2_device_unregister(v4l2_dev);
		release_region(zol->io, 2);
		return -EINVAL;
	}
	v4l2_info(v4l2_dev, "Zoltrix Radio Plus card driver.\n");

	mutex_init(&zol->lock);

	/* mute card - prevents noisy bootups */

	/* this ensures that the volume is all the way down  */

	outb(0, zol->io);
	outb(0, zol->io);
	msleep(20);
	inb(zol->io + 3);

	zol->curvol = 0;
	zol->stereo = 1;

	return 0;
}

static void __exit zoltrix_exit(void)
{
	struct zoltrix *zol = &zoltrix_card;

	video_unregister_device(&zol->vdev);
	v4l2_device_unregister(&zol->v4l2_dev);
	release_region(zol->io, 2);
}

module_init(zoltrix_init);
module_exit(zoltrix_exit);