/*
   * GemTek radio card driver
   *
   * Copyright 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>
   *
   * Converted to the radio-isa framework by Hans Verkuil <hans.verkuil@cisco.com>
   * Converted to V4L2 API by Mauro Carvalho Chehab <mchehab@infradead.org>
   *
   * Note: this card seems to swap the left and right audio channels!
   *
   * 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			*/
  #include <linux/videodev2.h>	/* kernel radio structs		*/
  #include <linux/mutex.h>
  #include <linux/io.h>		/* outb, outb_p			*/
  #include <linux/pnp.h>
  #include <linux/slab.h>
  #include <media/v4l2-ioctl.h>
  #include <media/v4l2-device.h>
  #include "radio-isa.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("1.0.0");
  
  /*
   * 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
  
  #define GEMTEK_MAX 4
  
  static bool probe = CONFIG_RADIO_GEMTEK_PROBE;
  static bool hardmute;
  static int io[GEMTEK_MAX] = { [0] = CONFIG_RADIO_GEMTEK_PORT,
  			      [1 ... (GEMTEK_MAX - 1)] = -1 };
  static int radio_nr[GEMTEK_MAX]	= { [0 ... (GEMTEK_MAX - 1)] = -1 };
  
  module_param(probe, bool, 0444);
  MODULE_PARM_DESC(probe, "Enable automatic device probing.");
  
  module_param(hardmute, bool, 0644);
  MODULE_PARM_DESC(hardmute, "Enable 'hard muting' by shutting down PLL, may "
  	 "reduce static noise.");
  
  module_param_array(io, int, NULL, 0444);
  MODULE_PARM_DESC(io, "Force I/O ports 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_array(radio_nr, int, NULL, 0444);
  MODULE_PARM_DESC(radio_nr, "Radio device numbers");
  
  /*
   * 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 radio_isa_card isa;
  	bool muted;
  	u32 bu2614data;
  };
  
  #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)
  {
  	struct radio_isa_card *isa = &gt->isa;
  	int i, bit, q, mute;
  
  	mute = gt->muted ? GEMTEK_MT : 0x00;
  
  	outb_p(mute | GEMTEK_CE | GEMTEK_DA | GEMTEK_CK, isa->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, isa->io);
  		udelay(SHORT_DELAY);
  		outb_p(mute | GEMTEK_CE | bit | GEMTEK_CK, isa->io);
  		udelay(SHORT_DELAY);
  	}
  
  	outb_p(mute | GEMTEK_DA | GEMTEK_CK, isa->io);
  	udelay(SHORT_DELAY);
  }
  
  /*
   * 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;
  }
  
  static struct radio_isa_card *gemtek_alloc(void)
  {
  	struct gemtek *gt = kzalloc(sizeof(*gt), GFP_KERNEL);
  
  	if (gt)
  		gt->muted = true;
  	return gt ? &gt->isa : NULL;
  }
  
  /*
   * Set FM-frequency.
   */
  static int gemtek_s_frequency(struct radio_isa_card *isa, u32 freq)
  {
  	struct gemtek *gt = container_of(isa, struct gemtek, isa);
  
  	if (hardmute && gt->muted)
  		return 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);
  	return 0;
  }
  
  /*
   * Set mute flag.
   */
  static int gemtek_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
  {
  	struct gemtek *gt = container_of(isa, struct gemtek, isa);
  	int i;
  
  	gt->muted = mute;
  	if (hardmute) {
  		if (!mute)
  			return gemtek_s_frequency(isa, isa->freq);
  
  		/* 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 0;
  	}
  
  	/* Read bus contents (CE, CK and DA). */
  	i = inb_p(isa->io);
  	/* Write it back with mute flag set. */
  	outb_p((i >> 5) | (mute ? GEMTEK_MT : 0), isa->io);
  	udelay(SHORT_DELAY);
  	return 0;
  }
  
  static u32 gemtek_g_rxsubchans(struct radio_isa_card *isa)
  {
  	if (inb_p(isa->io) & GEMTEK_NS)
  		return V4L2_TUNER_SUB_MONO;
  	return V4L2_TUNER_SUB_STEREO;
  }
  
  /*
   * Check if requested card acts like GemTek Radio card.
   */
  static bool gemtek_probe(struct radio_isa_card *isa, int io)
  {
  	int i, q;
  
  	q = inb_p(io);	/* 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, io);
  		udelay(SHORT_DELAY);
  
  		if ((inb_p(io) & ~GEMTEK_NS) != (0x17 | (1 << (i + 5))))
  			return false;
  	}
  	outb_p(q >> 5, io);	/* Write bus contents back. */
  	udelay(SHORT_DELAY);
  	return true;
  }
  
  static const struct radio_isa_ops gemtek_ops = {
  	.alloc = gemtek_alloc,
  	.probe = gemtek_probe,
  	.s_mute_volume = gemtek_s_mute_volume,
  	.s_frequency = gemtek_s_frequency,
  	.g_rxsubchans = gemtek_g_rxsubchans,
  };
  
  static const int gemtek_ioports[] = { 0x20c, 0x30c, 0x24c, 0x34c, 0x248, 0x28c };
  
  #ifdef CONFIG_PNP
  static struct pnp_device_id gemtek_pnp_devices[] = {
  	/* AOpen FX-3D/Pro Radio */
  	{.id = "ADS7183", .driver_data = 0},
  	{.id = ""}
  };
  
  MODULE_DEVICE_TABLE(pnp, gemtek_pnp_devices);
  #endif
  
  static struct radio_isa_driver gemtek_driver = {
  	.driver = {
  		.match		= radio_isa_match,
  		.probe		= radio_isa_probe,
  		.remove		= radio_isa_remove,
  		.driver		= {
  			.name	= "radio-gemtek",
  		},
  	},
  #ifdef CONFIG_PNP
  	.pnp_driver = {
  		.name		= "radio-gemtek",
  		.id_table	= gemtek_pnp_devices,
  		.probe		= radio_isa_pnp_probe,
  		.remove		= radio_isa_pnp_remove,
  	},
  #endif
  	.io_params = io,
  	.radio_nr_params = radio_nr,
  	.io_ports = gemtek_ioports,
  	.num_of_io_ports = ARRAY_SIZE(gemtek_ioports),
  	.region_size = 1,
  	.card = "GemTek Radio",
  	.ops = &gemtek_ops,
  	.has_stereo = true,
  };
  
  static int __init gemtek_init(void)
  {
  	gemtek_driver.probe = probe;
  #ifdef CONFIG_PNP
  	pnp_register_driver(&gemtek_driver.pnp_driver);
  #endif
  	return isa_register_driver(&gemtek_driver.driver, GEMTEK_MAX);
  }
  
  static void __exit gemtek_exit(void)
  {
  	hardmute = 1;	/* Turn off PLL */
  #ifdef CONFIG_PNP
  	pnp_unregister_driver(&gemtek_driver.pnp_driver);
  #endif
  	isa_unregister_driver(&gemtek_driver.driver);
  }
  
  module_init(gemtek_init);
  module_exit(gemtek_exit);