/* SF16FMR2 radio driver for Linux radio support
 * heavily based on fmi driver...
 * (c) 2000-2002 Ziglio Frediano, freddy77@angelfire.com
 *
 * Notes on the hardware
 *
 *  Frequency control is done digitally -- ie out(port,encodefreq(95.8));
 *  No volume control - only mute/unmute - you have to use line volume
 *
 *  For read stereo/mono you must wait 0.1 sec after set frequency and
 *  card unmuted so I set frequency on unmute
 *  Signal handling seem to work only on autoscanning (not implemented)
 *
 *  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			*/
#include <asm/io.h>		/* outb, outb_p			*/
#include <asm/uaccess.h>	/* copy to/from user		*/
#include <linux/videodev2.h>	/* kernel radio structs		*/
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <linux/mutex.h>

static struct mutex lock;

#include <linux/version.h>      /* for KERNEL_VERSION MACRO     */
#define RADIO_VERSION KERNEL_VERSION(0,0,2)

#define AUD_VOL_INDEX 1

static struct v4l2_queryctrl radio_qctrl[] = {
	{
		.id            = V4L2_CID_AUDIO_MUTE,
		.name          = "Mute",
		.minimum       = 0,
		.maximum       = 1,
		.default_value = 1,
		.type          = V4L2_CTRL_TYPE_BOOLEAN,
	},
	[AUD_VOL_INDEX] = {
		.id            = V4L2_CID_AUDIO_VOLUME,
		.name          = "Volume",
		.minimum       = 0,
		.maximum       = 15,
		.step          = 1,
		.default_value = 0,
		.type          = V4L2_CTRL_TYPE_INTEGER,
	}
};

#undef DEBUG
//#define DEBUG 1

#ifdef DEBUG
# define  debug_print(s) printk s
#else
# define  debug_print(s)
#endif

/* this should be static vars for module size */
struct fmr2_device
{
	unsigned long in_use;
	int port;
	int curvol; /* 0-15 */
	int mute;
	int stereo; /* card is producing stereo audio */
	unsigned long curfreq; /* freq in kHz */
	int card_type;
	__u32 flags;
};

static int io = 0x384;
static int radio_nr = -1;

/* hw precision is 12.5 kHz
 * It is only useful to give freq in intervall of 200 (=0.0125Mhz),
 * other bits will be truncated
 */
#define RSF16_ENCODE(x)	((x)/200+856)
#define RSF16_MINFREQ 87*16000
#define RSF16_MAXFREQ 108*16000

static inline void wait(int n,int port)
{
	for (;n;--n) inb(port);
}

static void outbits(int bits, unsigned int data, int nWait, int port)
{
	int bit;
	for(;--bits>=0;) {
		bit = (data>>bits) & 1;
		outb(bit,port);
		wait(nWait,port);
		outb(bit|2,port);
		wait(nWait,port);
		outb(bit,port);
		wait(nWait,port);
	}
}

static inline void fmr2_mute(int port)
{
	outb(0x00, port);
	wait(4,port);
}

static inline void fmr2_unmute(int port)
{
	outb(0x04, port);
	wait(4,port);
}

static inline int fmr2_stereo_mode(int port)
{
	int n = inb(port);
	outb(6,port);
	inb(port);
	n = ((n>>3)&1)^1;
	debug_print((KERN_DEBUG "stereo: %d\n", n));
	return n;
}

static int fmr2_product_info(struct fmr2_device *dev)
{
	int n = inb(dev->port);
	n &= 0xC1;
	if (n == 0)
	{
		/* this should support volume set */
		dev->card_type = 12;
		return 0;
	}
	/* not volume (mine is 11) */
	dev->card_type = (n==128)?11:0;
	return n;
}

static inline int fmr2_getsigstr(struct fmr2_device *dev)
{
	/* !!! work only if scanning freq */
	int port = dev->port, res = 0xffff;
	outb(5,port);
	wait(4,port);
	if (!(inb(port)&1)) res = 0;
	debug_print((KERN_DEBUG "signal: %d\n", res));
	return res;
}

/* set frequency and unmute card */
static int fmr2_setfreq(struct fmr2_device *dev)
{
	int port = dev->port;
	unsigned long freq = dev->curfreq;

	fmr2_mute(port);

	/* 0x42 for mono output
	 * 0x102 forward scanning
	 * 0x182 scansione avanti
	 */
	outbits(9,0x2,3,port);
	outbits(16,RSF16_ENCODE(freq),2,port);

	fmr2_unmute(port);

	/* wait 0.11 sec */
	msleep(110);

	/* NOTE if mute this stop radio
	   you must set freq on unmute */
	dev->stereo = fmr2_stereo_mode(port);
	return 0;
}

/* !!! not tested, in my card this does't work !!! */
static int fmr2_setvolume(struct fmr2_device *dev)
{
	int vol[16] = { 0x021, 0x084, 0x090, 0x104,
			0x110, 0x204, 0x210, 0x402,
			0x404, 0x408, 0x410, 0x801,
			0x802, 0x804, 0x808, 0x810 };
	int i, a, port = dev->port;
	int n = vol[dev->curvol & 0x0f];

	if (dev->card_type != 11)
		return 1;

	for (i = 12; --i >= 0; ) {
		a = ((n >> i) & 1) << 6; /* if (a=0) a= 0; else a= 0x40; */
		outb(a | 4, port);
		wait(4, port);
		outb(a | 0x24, port);
		wait(4, port);
		outb(a | 4, port);
		wait(4, port);
	}
	for (i = 6; --i >= 0; ) {
		a = ((0x18 >> i) & 1) << 6;
		outb(a | 4, port);
		wait(4,port);
		outb(a | 0x24, port);
		wait(4,port);
		outb(a|4, port);
		wait(4,port);
	}
	wait(4, port);
	outb(0x14, port);

	return 0;
}

static int vidioc_querycap(struct file *file, void  *priv,
					struct v4l2_capability *v)
{
	strlcpy(v->driver, "radio-sf16fmr2", sizeof(v->driver));
	strlcpy(v->card, "SF16-FMR2 radio", sizeof(v->card));
	sprintf(v->bus_info, "ISA");
	v->version = RADIO_VERSION;
	v->capabilities = V4L2_CAP_TUNER;
	return 0;
}

static int vidioc_g_tuner(struct file *file, void *priv,
					struct v4l2_tuner *v)
{
	int mult;
	struct fmr2_device *fmr2 = video_drvdata(file);

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

	strcpy(v->name, "FM");
	v->type = V4L2_TUNER_RADIO;

	mult = (fmr2->flags & V4L2_TUNER_CAP_LOW) ? 1 : 1000;
	v->rangelow = RSF16_MINFREQ/mult;
	v->rangehigh = RSF16_MAXFREQ/mult;
	v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_MODE_STEREO;
	v->capability = fmr2->flags&V4L2_TUNER_CAP_LOW;
	v->audmode = fmr2->stereo ? V4L2_TUNER_MODE_STEREO:
				V4L2_TUNER_MODE_MONO;
	mutex_lock(&lock);
	v->signal = fmr2_getsigstr(fmr2);
	mutex_unlock(&lock);
	return 0;
}

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

static int vidioc_s_frequency(struct file *file, void *priv,
					struct v4l2_frequency *f)
{
	struct fmr2_device *fmr2 = video_drvdata(file);

	if (!(fmr2->flags & V4L2_TUNER_CAP_LOW))
		f->frequency *= 1000;
	if (f->frequency < RSF16_MINFREQ ||
			f->frequency > RSF16_MAXFREQ )
		return -EINVAL;
	/*rounding in steps of 200 to match th freq
	that will be used */
	fmr2->curfreq = (f->frequency/200)*200;

	/* set card freq (if not muted) */
	if (fmr2->curvol && !fmr2->mute) {
		mutex_lock(&lock);
		fmr2_setfreq(fmr2);
		mutex_unlock(&lock);
	}
	return 0;
}

static int vidioc_g_frequency(struct file *file, void *priv,
					struct v4l2_frequency *f)
{
	struct fmr2_device *fmr2 = video_drvdata(file);

	f->type = V4L2_TUNER_RADIO;
	f->frequency = fmr2->curfreq;
	if (!(fmr2->flags & V4L2_TUNER_CAP_LOW))
		f->frequency /= 1000;
	return 0;
}

static int vidioc_queryctrl(struct file *file, void *priv,
					struct v4l2_queryctrl *qc)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(radio_qctrl); i++) {
		if (qc->id && qc->id == radio_qctrl[i].id) {
			memcpy(qc, &radio_qctrl[i], sizeof(*qc));
			return 0;
		}
	}
	return -EINVAL;
}

static int vidioc_g_ctrl(struct file *file, void *priv,
					struct v4l2_control *ctrl)
{
	struct fmr2_device *fmr2 = video_drvdata(file);

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
		ctrl->value = fmr2->mute;
		return 0;
	case V4L2_CID_AUDIO_VOLUME:
		ctrl->value = fmr2->curvol;
		return 0;
	}
	return -EINVAL;
}

static int vidioc_s_ctrl(struct file *file, void *priv,
					struct v4l2_control *ctrl)
{
	struct fmr2_device *fmr2 = video_drvdata(file);

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
		fmr2->mute = ctrl->value;
		break;
	case V4L2_CID_AUDIO_VOLUME:
		if (ctrl->value > radio_qctrl[AUD_VOL_INDEX].maximum)
			fmr2->curvol = radio_qctrl[AUD_VOL_INDEX].maximum;
		else
			fmr2->curvol = ctrl->value;

		break;
	default:
		return -EINVAL;
	}

#ifdef DEBUG
	if (fmr2->curvol && !fmr2->mute)
		printk(KERN_DEBUG "unmute\n");
	else
		printk(KERN_DEBUG "mute\n");
#endif

	mutex_lock(&lock);
	if (fmr2->curvol && !fmr2->mute) {
		fmr2_setvolume(fmr2);
		/* Set frequency and unmute card */
		fmr2_setfreq(fmr2);
	} else
		fmr2_mute(fmr2->port);
	mutex_unlock(&lock);
	return 0;
}

static int vidioc_g_audio(struct file *file, void *priv,
					struct v4l2_audio *a)
{
	if (a->index > 1)
		return -EINVAL;

	strcpy(a->name, "Radio");
	a->capability = V4L2_AUDCAP_STEREO;
	return 0;
}

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)
{
	if (i != 0)
		return -EINVAL;
	return 0;
}

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

static struct fmr2_device fmr2_unit;

static int fmr2_exclusive_open(struct file *file)
{
	return test_and_set_bit(0, &fmr2_unit.in_use) ? -EBUSY : 0;
}

static int fmr2_exclusive_release(struct file *file)
{
	clear_bit(0, &fmr2_unit.in_use);
	return 0;
}

static const struct v4l2_file_operations fmr2_fops = {
	.owner          = THIS_MODULE,
	.open           = fmr2_exclusive_open,
	.release        = fmr2_exclusive_release,
	.ioctl          = video_ioctl2,
};

static const struct v4l2_ioctl_ops fmr2_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 struct video_device fmr2_radio = {
	.name		= "SF16FMR2 radio",
	.fops		= &fmr2_fops,
	.ioctl_ops 	= &fmr2_ioctl_ops,
	.release	= video_device_release_empty,
};

static int __init fmr2_init(void)
{
	fmr2_unit.port = io;
	fmr2_unit.curvol = 0;
	fmr2_unit.mute = 0;
	fmr2_unit.curfreq = 0;
	fmr2_unit.stereo = 1;
	fmr2_unit.flags = V4L2_TUNER_CAP_LOW;
	fmr2_unit.card_type = 0;
	video_set_drvdata(&fmr2_radio, &fmr2_unit);

	mutex_init(&lock);

	if (!request_region(io, 2, "sf16fmr2")) {
		printk(KERN_ERR "radio-sf16fmr2: request_region failed!\n");
		return -EBUSY;
	}

	if (video_register_device(&fmr2_radio, VFL_TYPE_RADIO, radio_nr) < 0) {
		release_region(io, 2);
		return -EINVAL;
	}

	printk(KERN_INFO "SF16FMR2 radio card driver at 0x%x.\n", io);
	/* mute card - prevents noisy bootups */
	mutex_lock(&lock);
	fmr2_mute(io);
	fmr2_product_info(&fmr2_unit);
	mutex_unlock(&lock);
	debug_print((KERN_DEBUG "card_type %d\n", fmr2_unit.card_type));

	/* Only card_type == 11 implements volume */
	if (fmr2_unit.card_type != 11)
		radio_qctrl[AUD_VOL_INDEX].maximum = 1;

	return 0;
}

MODULE_AUTHOR("Ziglio Frediano, freddy77@angelfire.com");
MODULE_DESCRIPTION("A driver for the SF16FMR2 radio.");
MODULE_LICENSE("GPL");

module_param(io, int, 0);
MODULE_PARM_DESC(io, "I/O address of the SF16FMR2 card (should be 0x384, if do not work try 0x284)");
module_param(radio_nr, int, 0);

static void __exit fmr2_cleanup_module(void)
{
	video_unregister_device(&fmr2_radio);
	release_region(io,2);
}

module_init(fmr2_init);
module_exit(fmr2_cleanup_module);

#ifndef MODULE

static int __init fmr2_setup_io(char *str)
{
	get_option(&str, &io);
	return 1;
}

__setup("sf16fmr2=", fmr2_setup_io);

#endif