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radio-typhoon.c
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1 /* Typhoon Radio Card driver for radio support
2  * (c) 1999 Dr. Henrik Seidel <[email protected]>
3  *
4  * Notes on the hardware
5  *
6  * This card has two output sockets, one for speakers and one for line.
7  * The speaker output has volume control, but only in four discrete
8  * steps. The line output has neither volume control nor mute.
9  *
10  * The card has auto-stereo according to its manual, although it all
11  * sounds mono to me (even with the Win/DOS drivers). Maybe it's my
12  * antenna - I really don't know for sure.
13  *
14  * Frequency control is done digitally.
15  *
16  * Volume control is done digitally, but there are only four different
17  * possible values. So you should better always turn the volume up and
18  * use line control. I got the best results by connecting line output
19  * to the sound card microphone input. For such a configuration the
20  * volume control has no effect, since volume control only influences
21  * the speaker output.
22  *
23  * There is no explicit mute/unmute. So I set the radio frequency to a
24  * value where I do expect just noise and turn the speaker volume down.
25  * The frequency change is necessary since the card never seems to be
26  * completely silent.
27  *
28  * Converted to V4L2 API by Mauro Carvalho Chehab <[email protected]>
29  */
30 
31 #include <linux/module.h> /* Modules */
32 #include <linux/init.h> /* Initdata */
33 #include <linux/ioport.h> /* request_region */
34 #include <linux/videodev2.h> /* kernel radio structs */
35 #include <linux/io.h> /* outb, outb_p */
36 #include <linux/slab.h>
37 #include <media/v4l2-device.h>
38 #include <media/v4l2-ioctl.h>
39 #include "radio-isa.h"
40 
41 #define DRIVER_VERSION "0.1.2"
42 
43 MODULE_AUTHOR("Dr. Henrik Seidel");
44 MODULE_DESCRIPTION("A driver for the Typhoon radio card (a.k.a. EcoRadio).");
45 MODULE_LICENSE("GPL");
46 MODULE_VERSION("0.1.99");
47 
48 #ifndef CONFIG_RADIO_TYPHOON_PORT
49 #define CONFIG_RADIO_TYPHOON_PORT -1
50 #endif
51 
52 #ifndef CONFIG_RADIO_TYPHOON_MUTEFREQ
53 #define CONFIG_RADIO_TYPHOON_MUTEFREQ 87000
54 #endif
55 
56 #define TYPHOON_MAX 2
57 
58 static int io[TYPHOON_MAX] = { [0] = CONFIG_RADIO_TYPHOON_PORT,
59  [1 ... (TYPHOON_MAX - 1)] = -1 };
60 static int radio_nr[TYPHOON_MAX] = { [0 ... (TYPHOON_MAX - 1)] = -1 };
61 static unsigned long mutefreq = CONFIG_RADIO_TYPHOON_MUTEFREQ;
62 
63 module_param_array(io, int, NULL, 0444);
64 MODULE_PARM_DESC(io, "I/O addresses of the Typhoon card (0x316 or 0x336)");
65 module_param_array(radio_nr, int, NULL, 0444);
66 MODULE_PARM_DESC(radio_nr, "Radio device numbers");
67 module_param(mutefreq, ulong, 0);
68 MODULE_PARM_DESC(mutefreq, "Frequency used when muting the card (in kHz)");
69 
70 struct typhoon {
72  int muted;
73 };
74 
75 static struct radio_isa_card *typhoon_alloc(void)
76 {
77  struct typhoon *ty = kzalloc(sizeof(*ty), GFP_KERNEL);
78 
79  return ty ? &ty->isa : NULL;
80 }
81 
82 static int typhoon_s_frequency(struct radio_isa_card *isa, u32 freq)
83 {
84  unsigned long outval;
85  unsigned long x;
86 
87  /*
88  * The frequency transfer curve is not linear. The best fit I could
89  * get is
90  *
91  * outval = -155 + exp((f + 15.55) * 0.057))
92  *
93  * where frequency f is in MHz. Since we don't have exp in the kernel,
94  * I approximate this function by a third order polynomial.
95  *
96  */
97 
98  x = freq / 160;
99  outval = (x * x + 2500) / 5000;
100  outval = (outval * x + 5000) / 10000;
101  outval -= (10 * x * x + 10433) / 20866;
102  outval += 4 * x - 11505;
103 
104  outb_p((outval >> 8) & 0x01, isa->io + 4);
105  outb_p(outval >> 9, isa->io + 6);
106  outb_p(outval & 0xff, isa->io + 8);
107  return 0;
108 }
109 
110 static int typhoon_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
111 {
112  struct typhoon *ty = container_of(isa, struct typhoon, isa);
113 
114  if (mute)
115  vol = 0;
116  vol >>= 14; /* Map 16 bit to 2 bit */
117  vol &= 3;
118  outb_p(vol / 2, isa->io); /* Set the volume, high bit. */
119  outb_p(vol % 2, isa->io + 2); /* Set the volume, low bit. */
120 
121  if (vol == 0 && !ty->muted) {
122  ty->muted = true;
123  return typhoon_s_frequency(isa, mutefreq << 4);
124  }
125  if (vol && ty->muted) {
126  ty->muted = false;
127  return typhoon_s_frequency(isa, isa->freq);
128  }
129  return 0;
130 }
131 
132 static const struct radio_isa_ops typhoon_ops = {
133  .alloc = typhoon_alloc,
134  .s_mute_volume = typhoon_s_mute_volume,
135  .s_frequency = typhoon_s_frequency,
136 };
137 
138 static const int typhoon_ioports[] = { 0x316, 0x336 };
139 
140 static struct radio_isa_driver typhoon_driver = {
141  .driver = {
142  .match = radio_isa_match,
143  .probe = radio_isa_probe,
144  .remove = radio_isa_remove,
145  .driver = {
146  .name = "radio-typhoon",
147  },
148  },
149  .io_params = io,
150  .radio_nr_params = radio_nr,
151  .io_ports = typhoon_ioports,
152  .num_of_io_ports = ARRAY_SIZE(typhoon_ioports),
153  .region_size = 8,
154  .card = "Typhoon Radio",
155  .ops = &typhoon_ops,
156  .has_stereo = true,
157  .max_volume = 3,
158 };
159 
160 static int __init typhoon_init(void)
161 {
162  if (mutefreq < 87000 || mutefreq > 108000) {
163  printk(KERN_ERR "%s: You must set a frequency (in kHz) used when muting the card,\n",
164  typhoon_driver.driver.driver.name);
165  printk(KERN_ERR "%s: e.g. with \"mutefreq=87500\" (87000 <= mutefreq <= 108000)\n",
166  typhoon_driver.driver.driver.name);
167  return -ENODEV;
168  }
169  return isa_register_driver(&typhoon_driver.driver, TYPHOON_MAX);
170 }
171 
172 static void __exit typhoon_exit(void)
173 {
174  isa_unregister_driver(&typhoon_driver.driver);
175 }
176 
177 
178 module_init(typhoon_init);
179 module_exit(typhoon_exit);
180