/*
   * Zoltrix Radio Plus driver
   * Copyright 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>
   *
   * Converted to the radio-isa framework by Hans Verkuil <hans.verkuil@cisco.com>
   *
   * Note that this is the driver for the Zoltrix Radio Plus.
   * This driver does not work for the Zoltrix Radio Plus 108 or the
   * Zoltrix Radio Plus for Windows.
   *
   * Fully tested with the Keene USB FM Transmitter and the v4l2-compliance tool.
   */
  
  #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/io.h>		/* outb, outb_p                   */
  #include <linux/slab.h>
  #include <media/v4l2-device.h>
  #include <media/v4l2-ioctl.h>
  #include "radio-isa.h"
  
  MODULE_AUTHOR("C. van Schaik");
  MODULE_DESCRIPTION("A driver for the Zoltrix Radio Plus.");
  MODULE_LICENSE("GPL");
  MODULE_VERSION("0.1.99");
  
  #ifndef CONFIG_RADIO_ZOLTRIX_PORT
  #define CONFIG_RADIO_ZOLTRIX_PORT -1
  #endif
  
  #define ZOLTRIX_MAX 2
  
  static int io[ZOLTRIX_MAX] = { [0] = CONFIG_RADIO_ZOLTRIX_PORT,
  			       [1 ... (ZOLTRIX_MAX - 1)] = -1 };
  static int radio_nr[ZOLTRIX_MAX] = { [0 ... (ZOLTRIX_MAX - 1)] = -1 };
  
  module_param_array(io, int, NULL, 0444);
  MODULE_PARM_DESC(io, "I/O addresses of the Zoltrix Radio Plus card (0x20c or 0x30c)");
  module_param_array(radio_nr, int, NULL, 0444);
  MODULE_PARM_DESC(radio_nr, "Radio device numbers");
  
  struct zoltrix {
  	struct radio_isa_card isa;
  	int curvol;
  	bool muted;
  };
  
  static struct radio_isa_card *zoltrix_alloc(void)
  {
  	struct zoltrix *zol = kzalloc(sizeof(*zol), GFP_KERNEL);
  
  	return zol ? &zol->isa : NULL;
  }
  
  static int zoltrix_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
  {
  	struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
  
  	zol->curvol = vol;
  	zol->muted = mute;
  	if (mute || vol == 0) {
  		outb(0, isa->io);
  		outb(0, isa->io);
  		inb(isa->io + 3);            /* Zoltrix needs to be read to confirm */
  		return 0;
  	}
  
  	outb(vol - 1, isa->io);
  	msleep(10);
  	inb(isa->io + 2);
  	return 0;
  }
  
  /* tunes the radio to the desired frequency */
  static int zoltrix_s_frequency(struct radio_isa_card *isa, u32 freq)
  {
  	struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
  	struct v4l2_device *v4l2_dev = &isa->v4l2_dev;
  	unsigned long long bitmask, f, m;
  	bool stereo = isa->stereo;
  	int i;
  
  	if (freq == 0) {
  		v4l2_warn(v4l2_dev, "cannot set a frequency of 0.
  ");
  		return -EINVAL;
  	}
  
  	m = (freq / 160 - 8800) * 2;
  	f = (unsigned long long)m + 0x4d1c;
  
  	bitmask = 0xc480402c10080000ull;
  	i = 45;
  
  	outb(0, isa->io);
  	outb(0, isa->io);
  	inb(isa->io + 3);            /* Zoltrix needs to be read to confirm */
  
  	outb(0x40, isa->io);
  	outb(0xc0, isa->io);
  
  	bitmask = (bitmask ^ ((f & 0xff) << 47) ^ ((f & 0xff00) << 30) ^ (stereo << 31));
  	while (i--) {
  		if ((bitmask & 0x8000000000000000ull) != 0) {
  			outb(0x80, isa->io);
  			udelay(50);
  			outb(0x00, isa->io);
  			udelay(50);
  			outb(0x80, isa->io);
  			udelay(50);
  		} else {
  			outb(0xc0, isa->io);
  			udelay(50);
  			outb(0x40, isa->io);
  			udelay(50);
  			outb(0xc0, isa->io);
  			udelay(50);
  		}
  		bitmask *= 2;
  	}
  	/* termination sequence */
  	outb(0x80, isa->io);
  	outb(0xc0, isa->io);
  	outb(0x40, isa->io);
  	udelay(1000);
  	inb(isa->io + 2);
  	udelay(1000);
  
  	return zoltrix_s_mute_volume(isa, zol->muted, zol->curvol);
  }
  
  /* Get signal strength */
  static u32 zoltrix_g_rxsubchans(struct radio_isa_card *isa)
  {
  	struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
  	int a, b;
  
  	outb(0x00, isa->io);         /* This stuff I found to do nothing */
  	outb(zol->curvol, isa->io);
  	msleep(20);
  
  	a = inb(isa->io);
  	msleep(10);
  	b = inb(isa->io);
  
  	return (a == b && a == 0xcf) ?
  		V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
  }
  
  static u32 zoltrix_g_signal(struct radio_isa_card *isa)
  {
  	struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
  	int a, b;
  
  	outb(0x00, isa->io);         /* This stuff I found to do nothing */
  	outb(zol->curvol, isa->io);
  	msleep(20);
  
  	a = inb(isa->io);
  	msleep(10);
  	b = inb(isa->io);
  
  	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) ? 0xffff : 0;
  }
  
  static int zoltrix_s_stereo(struct radio_isa_card *isa, bool stereo)
  {
  	return zoltrix_s_frequency(isa, isa->freq);
  }
  
  static const struct radio_isa_ops zoltrix_ops = {
  	.alloc = zoltrix_alloc,
  	.s_mute_volume = zoltrix_s_mute_volume,
  	.s_frequency = zoltrix_s_frequency,
  	.s_stereo = zoltrix_s_stereo,
  	.g_rxsubchans = zoltrix_g_rxsubchans,
  	.g_signal = zoltrix_g_signal,
  };
  
  static const int zoltrix_ioports[] = { 0x20c, 0x30c };
  
  static struct radio_isa_driver zoltrix_driver = {
  	.driver = {
  		.match		= radio_isa_match,
  		.probe		= radio_isa_probe,
  		.remove		= radio_isa_remove,
  		.driver		= {
  			.name	= "radio-zoltrix",
  		},
  	},
  	.io_params = io,
  	.radio_nr_params = radio_nr,
  	.io_ports = zoltrix_ioports,
  	.num_of_io_ports = ARRAY_SIZE(zoltrix_ioports),
  	.region_size = 2,
  	.card = "Zoltrix Radio Plus",
  	.ops = &zoltrix_ops,
  	.has_stereo = true,
  	.max_volume = 15,
  };
  
  static int __init zoltrix_init(void)
  {
  	return isa_register_driver(&zoltrix_driver.driver, ZOLTRIX_MAX);
  }
  
  static void __exit zoltrix_exit(void)
  {
  	isa_unregister_driver(&zoltrix_driver.driver);
  }
  
  module_init(zoltrix_init);
  module_exit(zoltrix_exit);