/* Terratec ActiveRadio ISA Standalone card driver for Linux radio support
   * (c) 1999 R. Offermanns (rolf@offermanns.de)
   * based on the aimslab radio driver from M. Kirkwood
   * many thanks to Michael Becker and Friedhelm Birth (from TerraTec)
   *
   *
   * History:
   * 1999-05-21	First preview release
   *
   *  Notes on the hardware:
   *  There are two "main" chips on the card:
   *  - Philips OM5610 (http://www-us.semiconductors.philips.com/acrobat/datasheets/OM5610_2.pdf)
   *  - Philips SAA6588 (http://www-us.semiconductors.philips.com/acrobat/datasheets/SAA6588_1.pdf)
   *  (you can get the datasheet at the above links)
   *
   *  Frequency control is done digitally -- ie out(port,encodefreq(95.8));
   *  Volume Control is done digitally
   *
   * Converted to the radio-isa framework by Hans Verkuil <hans.verkuil@cisco.com>
   * 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/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("R. Offermans & others");
  MODULE_DESCRIPTION("A driver for the TerraTec ActiveRadio Standalone radio card.");
  MODULE_LICENSE("GPL");
  MODULE_VERSION("0.1.99");
  
  /* Note: there seems to be only one possible port (0x590), but without
     hardware this is hard to verify. For now, this is the only one we will
     support. */
  static int io = 0x590;
  static int radio_nr = -1;
  
  module_param(radio_nr, int, 0444);
  MODULE_PARM_DESC(radio_nr, "Radio device number");
  
  #define WRT_DIS 	0x00
  #define CLK_OFF		0x00
  #define IIC_DATA	0x01
  #define IIC_CLK		0x02
  #define DATA		0x04
  #define CLK_ON 		0x08
  #define WRT_EN		0x10
  
  static struct radio_isa_card *terratec_alloc(void)
  {
  	return kzalloc(sizeof(struct radio_isa_card), GFP_KERNEL);
  }
  
  static int terratec_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
  {
  	int i;
  
  	if (mute)
  		vol = 0;
  	vol = vol + (vol * 32); /* change both channels */
  	for (i = 0; i < 8; i++) {
  		if (vol & (0x80 >> i))
  			outb(0x80, isa->io + 1);
  		else
  			outb(0x00, isa->io + 1);
  	}
  	return 0;
  }
  
  
  /* this is the worst part in this driver */
  /* many more or less strange things are going on here, but hey, it works :) */
  
  static int terratec_s_frequency(struct radio_isa_card *isa, u32 freq)
  {
  	int i;
  	int p;
  	int temp;
  	long rest;
  	unsigned char buffer[25];		/* we have to bit shift 25 registers */
  
  	freq = freq / 160;			/* convert the freq. to a nice to handle value */
  	memset(buffer, 0, sizeof(buffer));
  
  	rest = freq * 10 + 10700;	/* I once had understood what is going on here */
  					/* maybe some wise guy (friedhelm?) can comment this stuff */
  	i = 13;
  	p = 10;
  	temp = 102400;
  	while (rest != 0) {
  		if (rest % temp  == rest)
  			buffer[i] = 0;
  		else {
  			buffer[i] = 1;
  			rest = rest - temp;
  		}
  		i--;
  		p--;
  		temp = temp / 2;
  	}
  
  	for (i = 24; i > -1; i--) {	/* bit shift the values to the radiocard */
  		if (buffer[i] == 1) {
  			outb(WRT_EN | DATA, isa->io);
  			outb(WRT_EN | DATA | CLK_ON, isa->io);
  			outb(WRT_EN | DATA, isa->io);
  		} else {
  			outb(WRT_EN | 0x00, isa->io);
  			outb(WRT_EN | 0x00 | CLK_ON, isa->io);
  		}
  	}
  	outb(0x00, isa->io);
  	return 0;
  }
  
  static u32 terratec_g_signal(struct radio_isa_card *isa)
  {
  	/* bit set = no signal present	*/
  	return (inb(isa->io) & 2) ? 0 : 0xffff;
  }
  
  static const struct radio_isa_ops terratec_ops = {
  	.alloc = terratec_alloc,
  	.s_mute_volume = terratec_s_mute_volume,
  	.s_frequency = terratec_s_frequency,
  	.g_signal = terratec_g_signal,
  };
  
  static const int terratec_ioports[] = { 0x590 };
  
  static struct radio_isa_driver terratec_driver = {
  	.driver = {
  		.match		= radio_isa_match,
  		.probe		= radio_isa_probe,
  		.remove		= radio_isa_remove,
  		.driver		= {
  			.name	= "radio-terratec",
  		},
  	},
  	.io_params = &io,
  	.radio_nr_params = &radio_nr,
  	.io_ports = terratec_ioports,
  	.num_of_io_ports = ARRAY_SIZE(terratec_ioports),
  	.region_size = 2,
  	.card = "TerraTec ActiveRadio",
  	.ops = &terratec_ops,
  	.has_stereo = true,
  	.max_volume = 10,
  };
  
  static int __init terratec_init(void)
  {
  	return isa_register_driver(&terratec_driver.driver, 1);
  }
  
  static void __exit terratec_exit(void)
  {
  	isa_unregister_driver(&terratec_driver.driver);
  }
  
  module_init(terratec_init);
  module_exit(terratec_exit);