/* GemTek radio card driver for Linux (C) 1998 Jonas Munsin <jmunsin@iki.fi>
   *
   * GemTek hasn't released any specs on the card, so the protocol had to
   * be reverse engineered with dosemu.
   *
   * Besides the protocol changes, this is mostly a copy of:
   *
   *    RadioTrack II driver for Linux radio support (C) 1998 Ben Pfaff

   *

   *    Based on RadioTrack I/RadioReveal (C) 1997 M. Kirkwood

   *    Converted to new API by Alan Cox <alan@lxorguk.ukuu.org.uk>

   *    Various bugfixes and enhancements by Russell Kroll <rkroll@exploits.org>
   *
   * TODO: Allow for more than one of these foolish entities :-)
   *

   * 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 <linux/videodev2.h>	/* kernel radio structs		*/

  #include <linux/mutex.h>
  #include <linux/io.h>		/* outb, outb_p			*/

  #include <media/v4l2-ioctl.h>

  #include <media/v4l2-device.h>

  /*
   * Module info.
   */

  MODULE_AUTHOR("Jonas Munsin, Pekka Seppänen <pexu@kapsi.fi>");

  MODULE_DESCRIPTION("A driver for the GemTek Radio card.");
  MODULE_LICENSE("GPL");

  MODULE_VERSION("0.0.4");

  
  /*
   * Module params.
   */

  #ifndef CONFIG_RADIO_GEMTEK_PORT
  #define CONFIG_RADIO_GEMTEK_PORT -1
  #endif

  #ifndef CONFIG_RADIO_GEMTEK_PROBE
  #define CONFIG_RADIO_GEMTEK_PROBE 1
  #endif

  static int io		= CONFIG_RADIO_GEMTEK_PORT;

  static bool probe	= CONFIG_RADIO_GEMTEK_PROBE;
  static bool hardmute;
  static bool shutdown	= 1;
  static bool keepmuted	= 1;
  static bool initmute	= 1;

  static int radio_nr	= -1;

  module_param(io, int, 0444);

  MODULE_PARM_DESC(io, "Force I/O port for the GemTek Radio card if automatic "

  	 "probing is disabled or fails. The most common I/O ports are: 0x20c "
  	 "0x30c, 0x24c or 0x34c (0x20c, 0x248 and 0x28c have been reported to "

  	 "work for the combined sound/radiocard).");

  
  module_param(probe, bool, 0444);
  MODULE_PARM_DESC(probe, "Enable automatic device probing. Note: only the most "
  	"common I/O ports used by the card are probed.");
  
  module_param(hardmute, bool, 0644);
  MODULE_PARM_DESC(hardmute, "Enable `hard muting' by shutting down PLL, may "
  	 "reduce static noise.");
  
  module_param(shutdown, bool, 0644);
  MODULE_PARM_DESC(shutdown, "Enable shutting down PLL and muting line when "
  	 "module is unloaded.");
  
  module_param(keepmuted, bool, 0644);
  MODULE_PARM_DESC(keepmuted, "Keep card muted even when frequency is changed.");
  
  module_param(initmute, bool, 0444);
  MODULE_PARM_DESC(initmute, "Mute card when module is loaded.");
  
  module_param(radio_nr, int, 0444);
  
  /*
   * Functions for controlling the card.
   */
  #define GEMTEK_LOWFREQ	(87*16000)
  #define GEMTEK_HIGHFREQ	(108*16000)

  /*
   * Frequency calculation constants.  Intermediate frequency 10.52 MHz (nominal
   * value 10.7 MHz), reference divisor 6.39 kHz (nominal 6.25 kHz).
   */
  #define FSCALE		8
  #define IF_OFFSET	((unsigned int)(10.52 * 16000 * (1<<FSCALE)))
  #define REF_FREQ	((unsigned int)(6.39 * 16 * (1<<FSCALE)))

  #define GEMTEK_CK		0x01	/* Clock signal			*/
  #define GEMTEK_DA		0x02	/* Serial data			*/
  #define GEMTEK_CE		0x04	/* Chip enable			*/
  #define GEMTEK_NS		0x08	/* No signal			*/
  #define GEMTEK_MT		0x10	/* Line mute			*/
  #define GEMTEK_STDF_3_125_KHZ	0x01	/* Standard frequency 3.125 kHz	*/
  #define GEMTEK_PLL_OFF		0x07	/* PLL off			*/
  
  #define BU2614_BUS_SIZE	32	/* BU2614 / BU2614FS bus size		*/

  
  #define SHORT_DELAY 5		/* usec */
  #define LONG_DELAY 75		/* usec */

  struct gemtek {
  	struct v4l2_device v4l2_dev;
  	struct video_device vdev;
  	struct mutex lock;

  	unsigned long lastfreq;

  	int muted;

  	int verified;
  	int io;

  	u32 bu2614data;

  };

  static struct gemtek gemtek_card;

  #define BU2614_FREQ_BITS 	16 /* D0..D15, Frequency data		*/
  #define BU2614_PORT_BITS	3 /* P0..P2, Output port control data	*/
  #define BU2614_VOID_BITS	4 /* unused 				*/
  #define BU2614_FMES_BITS	1 /* CT, Frequency measurement beginning data */
  #define BU2614_STDF_BITS	3 /* R0..R2, Standard frequency data	*/
  #define BU2614_SWIN_BITS	1 /* S, Switch between FMIN / AMIN	*/
  #define BU2614_SWAL_BITS        1 /* PS, Swallow counter division (AMIN only)*/
  #define BU2614_VOID2_BITS	1 /* unused				*/
  #define BU2614_FMUN_BITS	1 /* GT, Frequency measurement time & unlock */
  #define BU2614_TEST_BITS	1 /* TS, Test data is input		*/
  
  #define BU2614_FREQ_SHIFT 	0
  #define BU2614_PORT_SHIFT	(BU2614_FREQ_BITS + BU2614_FREQ_SHIFT)
  #define BU2614_VOID_SHIFT	(BU2614_PORT_BITS + BU2614_PORT_SHIFT)
  #define BU2614_FMES_SHIFT	(BU2614_VOID_BITS + BU2614_VOID_SHIFT)
  #define BU2614_STDF_SHIFT	(BU2614_FMES_BITS + BU2614_FMES_SHIFT)
  #define BU2614_SWIN_SHIFT	(BU2614_STDF_BITS + BU2614_STDF_SHIFT)
  #define BU2614_SWAL_SHIFT	(BU2614_SWIN_BITS + BU2614_SWIN_SHIFT)
  #define BU2614_VOID2_SHIFT	(BU2614_SWAL_BITS + BU2614_SWAL_SHIFT)
  #define BU2614_FMUN_SHIFT	(BU2614_VOID2_BITS + BU2614_VOID2_SHIFT)
  #define BU2614_TEST_SHIFT	(BU2614_FMUN_BITS + BU2614_FMUN_SHIFT)
  
  #define MKMASK(field)	(((1<<BU2614_##field##_BITS) - 1) << \
  			BU2614_##field##_SHIFT)
  #define BU2614_PORT_MASK	MKMASK(PORT)
  #define BU2614_FREQ_MASK	MKMASK(FREQ)
  #define BU2614_VOID_MASK	MKMASK(VOID)
  #define BU2614_FMES_MASK	MKMASK(FMES)
  #define BU2614_STDF_MASK	MKMASK(STDF)
  #define BU2614_SWIN_MASK	MKMASK(SWIN)
  #define BU2614_SWAL_MASK	MKMASK(SWAL)
  #define BU2614_VOID2_MASK	MKMASK(VOID2)
  #define BU2614_FMUN_MASK	MKMASK(FMUN)
  #define BU2614_TEST_MASK	MKMASK(TEST)

  /*
   * Set data which will be sent to BU2614FS.

   */

  #define gemtek_bu2614_set(dev, field, data) ((dev)->bu2614data = \
  	((dev)->bu2614data & ~field##_MASK) | ((data) << field##_SHIFT))

  
  /*
   * Transmit settings to BU2614FS over GemTek IC.
   */

  static void gemtek_bu2614_transmit(struct gemtek *gt)

  {
  	int i, bit, q, mute;

  	mutex_lock(&gt->lock);

  	mute = gt->muted ? GEMTEK_MT : 0x00;

  	outb_p(mute | GEMTEK_DA | GEMTEK_CK, gt->io);

  	udelay(SHORT_DELAY);

  	outb_p(mute | GEMTEK_CE | GEMTEK_DA | GEMTEK_CK, gt->io);

  	udelay(LONG_DELAY);

  	for (i = 0, q = gt->bu2614data; i < 32; i++, q >>= 1) {
  		bit = (q & 1) ? GEMTEK_DA : 0;
  		outb_p(mute | GEMTEK_CE | bit, gt->io);
  		udelay(SHORT_DELAY);
  		outb_p(mute | GEMTEK_CE | bit | GEMTEK_CK, gt->io);
  		udelay(SHORT_DELAY);

  	}

  	outb_p(mute | GEMTEK_DA | GEMTEK_CK, gt->io);

  	udelay(SHORT_DELAY);

  	outb_p(mute | GEMTEK_CE | GEMTEK_DA | GEMTEK_CK, gt->io);

  	udelay(LONG_DELAY);

  	mutex_unlock(&gt->lock);

  }

  /*

   * Calculate divisor from FM-frequency for BU2614FS (3.125 KHz STDF expected).

   */

  static unsigned long gemtek_convfreq(unsigned long freq)

  {

  	return ((freq<<FSCALE) + IF_OFFSET + REF_FREQ/2) / REF_FREQ;

  }
  
  /*
   * Set FM-frequency.
   */

  static void gemtek_setfreq(struct gemtek *gt, unsigned long freq)

  {

  	if (keepmuted && hardmute && gt->muted)

  		return;

  	freq = clamp_val(freq, GEMTEK_LOWFREQ, GEMTEK_HIGHFREQ);

  	gt->lastfreq = freq;
  	gt->muted = 0;

  	gemtek_bu2614_set(gt, BU2614_PORT, 0);
  	gemtek_bu2614_set(gt, BU2614_FMES, 0);
  	gemtek_bu2614_set(gt, BU2614_SWIN, 0);	/* FM-mode	*/
  	gemtek_bu2614_set(gt, BU2614_SWAL, 0);
  	gemtek_bu2614_set(gt, BU2614_FMUN, 1);	/* GT bit set	*/
  	gemtek_bu2614_set(gt, BU2614_TEST, 0);

  	gemtek_bu2614_set(gt, BU2614_STDF, GEMTEK_STDF_3_125_KHZ);
  	gemtek_bu2614_set(gt, BU2614_FREQ, gemtek_convfreq(freq));

  	gemtek_bu2614_transmit(gt);

  }

  /*
   * Set mute flag.
   */

  static void gemtek_mute(struct gemtek *gt)

  {

  	int i;

  
  	gt->muted = 1;

  
  	if (hardmute) {
  		/* Turn off PLL, disable data output */

  		gemtek_bu2614_set(gt, BU2614_PORT, 0);
  		gemtek_bu2614_set(gt, BU2614_FMES, 0);	/* CT bit off	*/
  		gemtek_bu2614_set(gt, BU2614_SWIN, 0);	/* FM-mode	*/
  		gemtek_bu2614_set(gt, BU2614_SWAL, 0);
  		gemtek_bu2614_set(gt, BU2614_FMUN, 0);	/* GT bit off	*/
  		gemtek_bu2614_set(gt, BU2614_TEST, 0);
  		gemtek_bu2614_set(gt, BU2614_STDF, GEMTEK_PLL_OFF);
  		gemtek_bu2614_set(gt, BU2614_FREQ, 0);
  		gemtek_bu2614_transmit(gt);
  		return;
  	}

  	mutex_lock(&gt->lock);

  	/* Read bus contents (CE, CK and DA). */
  	i = inb_p(gt->io);
  	/* Write it back with mute flag set. */
  	outb_p((i >> 5) | GEMTEK_MT, gt->io);
  	udelay(SHORT_DELAY);
  
  	mutex_unlock(&gt->lock);

  }

  /*
   * Unset mute flag.
   */

  static void gemtek_unmute(struct gemtek *gt)

  {

  	int i;

  	gt->muted = 0;

  	if (hardmute) {
  		/* Turn PLL back on. */

  		gemtek_setfreq(gt, gt->lastfreq);
  		return;
  	}
  	mutex_lock(&gt->lock);

  	i = inb_p(gt->io);
  	outb_p(i >> 5, gt->io);
  	udelay(SHORT_DELAY);

  	mutex_unlock(&gt->lock);

  }

  /*
   * Get signal strength (= stereo status).
   */

  static inline int gemtek_getsigstr(struct gemtek *gt)

  {

  	int sig;
  
  	mutex_lock(&gt->lock);
  	sig = inb_p(gt->io) & GEMTEK_NS ? 0 : 1;
  	mutex_unlock(&gt->lock);
  	return sig;

  }

  /*
   * Check if requested card acts like GemTek Radio card.
   */

  static int gemtek_verify(struct gemtek *gt, int port)

  {

  	int i, q;

  	if (gt->verified == port)

  		return 1;

  	mutex_lock(&gt->lock);

  	q = inb_p(port);	/* Read bus contents before probing. */
  	/* Try to turn on CE, CK and DA respectively and check if card responds
  	   properly. */
  	for (i = 0; i < 3; ++i) {
  		outb_p(1 << i, port);
  		udelay(SHORT_DELAY);

  		if ((inb_p(port) & (~GEMTEK_NS)) != (0x17 | (1 << (i + 5)))) {

  			mutex_unlock(&gt->lock);

  			return 0;
  		}
  	}
  	outb_p(q >> 5, port);	/* Write bus contents back. */
  	udelay(SHORT_DELAY);

  	mutex_unlock(&gt->lock);
  	gt->verified = port;

  	return 1;

  }

  /*
   * Automatic probing for card.
   */

  static int gemtek_probe(struct gemtek *gt)

  {

  	struct v4l2_device *v4l2_dev = &gt->v4l2_dev;

  	int ioports[] = { 0x20c, 0x30c, 0x24c, 0x34c, 0x248, 0x28c };
  	int i;
  
  	if (!probe) {

  		v4l2_info(v4l2_dev, "Automatic device probing disabled.
  ");

  		return -1;
  	}

  	v4l2_info(v4l2_dev, "Automatic device probing enabled.
  ");

  
  	for (i = 0; i < ARRAY_SIZE(ioports); ++i) {

  		v4l2_info(v4l2_dev, "Trying I/O port 0x%x...
  ", ioports[i]);

  
  		if (!request_region(ioports[i], 1, "gemtek-probe")) {

  			v4l2_warn(v4l2_dev, "I/O port 0x%x busy!
  ",

  			       ioports[i]);
  			continue;
  		}

  		if (gemtek_verify(gt, ioports[i])) {
  			v4l2_info(v4l2_dev, "Card found from I/O port "

  			       "0x%x!
  ", ioports[i]);
  
  			release_region(ioports[i], 1);

  			gt->io = ioports[i];
  			return gt->io;

  		}
  
  		release_region(ioports[i], 1);
  	}

  	v4l2_err(v4l2_dev, "Automatic probing failed!
  ");

  	return -1;

  }

  /*
   * Video 4 Linux stuff.
   */

  static const struct v4l2_file_operations gemtek_fops = {

  	.owner		= THIS_MODULE,

  	.unlocked_ioctl	= video_ioctl2,

  };
  
  static int vidioc_querycap(struct file *file, void *priv,
  			   struct v4l2_capability *v)

  {
  	strlcpy(v->driver, "radio-gemtek", sizeof(v->driver));
  	strlcpy(v->card, "GemTek", sizeof(v->card));

  	strlcpy(v->bus_info, "ISA", sizeof(v->bus_info));

  	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 gemtek *gt = video_drvdata(file);

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

  	strlcpy(v->name, "FM", sizeof(v->name));

  	v->type = V4L2_TUNER_RADIO;

  	v->rangelow = GEMTEK_LOWFREQ;
  	v->rangehigh = GEMTEK_HIGHFREQ;
  	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;

  	v->signal = 0xffff * gemtek_getsigstr(gt);

  	if (v->signal) {
  		v->audmode = V4L2_TUNER_MODE_STEREO;
  		v->rxsubchans = V4L2_TUNER_SUB_STEREO;
  	} else {
  		v->audmode = V4L2_TUNER_MODE_MONO;
  		v->rxsubchans = V4L2_TUNER_SUB_MONO;
  	}

  	return 0;
  }

  static int vidioc_s_tuner(struct file *file, void *priv, struct v4l2_tuner *v)

  {

  	return (v->index != 0) ? -EINVAL : 0;

  }

  static int vidioc_g_frequency(struct file *file, void *priv,

  			      struct v4l2_frequency *f)

  {

  	struct gemtek *gt = video_drvdata(file);

  	if (f->tuner != 0)
  		return -EINVAL;
  	f->type = V4L2_TUNER_RADIO;
  	f->frequency = gt->lastfreq;

  	return 0;
  }

  static int vidioc_s_frequency(struct file *file, void *priv,

  			      struct v4l2_frequency *f)

  {

  	struct gemtek *gt = video_drvdata(file);

  	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
  		return -EINVAL;
  	gemtek_setfreq(gt, f->frequency);

  	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, 0);
  	default:
  		return -EINVAL;

  	}

  }

  static int vidioc_g_ctrl(struct file *file, void *priv,

  			 struct v4l2_control *ctrl)

  {

  	struct gemtek *gt = video_drvdata(file);

  	switch (ctrl->id) {
  	case V4L2_CID_AUDIO_MUTE:

  		ctrl->value = gt->muted;

  		return 0;
  	}
  	return -EINVAL;
  }
  
  static int vidioc_s_ctrl(struct file *file, void *priv,

  			 struct v4l2_control *ctrl)

  {

  	struct gemtek *gt = video_drvdata(file);

  
  	switch (ctrl->id) {
  	case V4L2_CID_AUDIO_MUTE:
  		if (ctrl->value)

  			gemtek_mute(gt);

  		else

  			gemtek_unmute(gt);

  		return 0;

  	}

  	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 != 0) ? -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 != 0) ? -EINVAL : 0;

  }

  static const struct v4l2_ioctl_ops gemtek_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

  };

  /*
   * Initialization / cleanup related stuff.
   */

  
  static int __init gemtek_init(void)
  {

  	struct gemtek *gt = &gemtek_card;
  	struct v4l2_device *v4l2_dev = &gt->v4l2_dev;
  	int res;

  	strlcpy(v4l2_dev->name, "gemtek", sizeof(v4l2_dev->name));

  	v4l2_info(v4l2_dev, "GemTek Radio card driver: v0.0.3
  ");
  
  	mutex_init(&gt->lock);
  
  	gt->verified = -1;
  	gt->io = io;
  	gemtek_probe(gt);
  	if (gt->io) {
  		if (!request_region(gt->io, 1, "gemtek")) {
  			v4l2_err(v4l2_dev, "I/O port 0x%x already in use.
  ", gt->io);

  			return -EBUSY;
  		}

  		if (!gemtek_verify(gt, gt->io))
  			v4l2_warn(v4l2_dev, "Card at I/O port 0x%x does not "

  			       "respond properly, check your "

  			       "configuration.
  ", gt->io);

  		else

  			v4l2_info(v4l2_dev, "Using I/O port 0x%x.
  ", gt->io);

  	} else if (probe) {

  		v4l2_err(v4l2_dev, "Automatic probing failed and no "

  		       "fixed I/O port defined.
  ");
  		return -ENODEV;
  	} else {

  		v4l2_err(v4l2_dev, "Automatic probing disabled but no fixed "

  		       "I/O port defined.");

  		return -EINVAL;
  	}

  	res = v4l2_device_register(NULL, v4l2_dev);
  	if (res < 0) {
  		v4l2_err(v4l2_dev, "Could not register v4l2_device
  ");
  		release_region(gt->io, 1);
  		return res;
  	}

  	strlcpy(gt->vdev.name, v4l2_dev->name, sizeof(gt->vdev.name));
  	gt->vdev.v4l2_dev = v4l2_dev;
  	gt->vdev.fops = &gemtek_fops;
  	gt->vdev.ioctl_ops = &gemtek_ioctl_ops;
  	gt->vdev.release = video_device_release_empty;
  	video_set_drvdata(&gt->vdev, gt);

  	/* Set defaults */

  	gt->lastfreq = GEMTEK_LOWFREQ;
  	gt->bu2614data = 0;

  	if (initmute)

  		gemtek_mute(gt);

  	if (video_register_device(&gt->vdev, VFL_TYPE_RADIO, radio_nr) < 0) {
  		v4l2_device_unregister(v4l2_dev);
  		release_region(gt->io, 1);
  		return -EBUSY;
  	}

  	return 0;
  }

  /*
   * Module cleanup
   */
  static void __exit gemtek_exit(void)

  {

  	struct gemtek *gt = &gemtek_card;
  	struct v4l2_device *v4l2_dev = &gt->v4l2_dev;

  	if (shutdown) {
  		hardmute = 1;	/* Turn off PLL */

  		gemtek_mute(gt);

  	} else {

  		v4l2_info(v4l2_dev, "Module unloaded but card not muted!
  ");

  	}

  	video_unregister_device(&gt->vdev);
  	v4l2_device_unregister(&gt->v4l2_dev);
  	release_region(gt->io, 1);

  }
  
  module_init(gemtek_init);

  module_exit(gemtek_exit);