radio-typhoon.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/* Typhoon Radio Card driver for radio support
  3 * (c) 1999 Dr. Henrik Seidel <Henrik.Seidel@gmx.de>
  4 *
  5 * Notes on the hardware
  6 *
  7 * This card has two output sockets, one for speakers and one for line.
  8 * The speaker output has volume control, but only in four discrete
  9 * steps. The line output has neither volume control nor mute.
 10 *
 11 * The card has auto-stereo according to its manual, although it all
 12 * sounds mono to me (even with the Win/DOS drivers). Maybe it's my
 13 * antenna - I really don't know for sure.
 14 *
 15 * Frequency control is done digitally.
 16 *
 17 * Volume control is done digitally, but there are only four different
 18 * possible values. So you should better always turn the volume up and
 19 * use line control. I got the best results by connecting line output
 20 * to the sound card microphone input. For such a configuration the
 21 * volume control has no effect, since volume control only influences
 22 * the speaker output.
 23 *
 24 * There is no explicit mute/unmute. So I set the radio frequency to a
 25 * value where I do expect just noise and turn the speaker volume down.
 26 * The frequency change is necessary since the card never seems to be
 27 * completely silent.
 28 *
 29 * Converted to V4L2 API by Mauro Carvalho Chehab <mchehab@kernel.org>
 30 */
 31
 32#include <linux/module.h>	/* Modules                        */
 33#include <linux/init.h>		/* Initdata                       */
 34#include <linux/ioport.h>	/* request_region		  */
 35#include <linux/videodev2.h>	/* kernel radio structs           */
 36#include <linux/io.h>		/* outb, outb_p                   */
 37#include <linux/slab.h>
 38#include <media/v4l2-device.h>
 39#include <media/v4l2-ioctl.h>
 40#include "radio-isa.h"
 41
 42#define DRIVER_VERSION "0.1.2"
 43
 44MODULE_AUTHOR("Dr. Henrik Seidel");
 45MODULE_DESCRIPTION("A driver for the Typhoon radio card (a.k.a. EcoRadio).");
 46MODULE_LICENSE("GPL");
 47MODULE_VERSION("0.1.99");
 48
 49#ifndef CONFIG_RADIO_TYPHOON_PORT
 50#define CONFIG_RADIO_TYPHOON_PORT -1
 51#endif
 52
 53#ifndef CONFIG_RADIO_TYPHOON_MUTEFREQ
 54#define CONFIG_RADIO_TYPHOON_MUTEFREQ 87000
 55#endif
 56
 57#define TYPHOON_MAX 2
 58
 59static int io[TYPHOON_MAX] = { [0] = CONFIG_RADIO_TYPHOON_PORT,
 60			      [1 ... (TYPHOON_MAX - 1)] = -1 };
 61static int radio_nr[TYPHOON_MAX]	= { [0 ... (TYPHOON_MAX - 1)] = -1 };
 62static unsigned long mutefreq = CONFIG_RADIO_TYPHOON_MUTEFREQ;
 63
 64module_param_array(io, int, NULL, 0444);
 65MODULE_PARM_DESC(io, "I/O addresses of the Typhoon card (0x316 or 0x336)");
 66module_param_array(radio_nr, int, NULL, 0444);
 67MODULE_PARM_DESC(radio_nr, "Radio device numbers");
 68module_param(mutefreq, ulong, 0);
 69MODULE_PARM_DESC(mutefreq, "Frequency used when muting the card (in kHz)");
 70
 71struct typhoon {
 72	struct radio_isa_card isa;
 73	int muted;
 74};
 75
 76static struct radio_isa_card *typhoon_alloc(void)
 77{
 78	struct typhoon *ty = kzalloc(sizeof(*ty), GFP_KERNEL);
 79
 80	return ty ? &ty->isa : NULL;
 81}
 82
 83static int typhoon_s_frequency(struct radio_isa_card *isa, u32 freq)
 84{
 85	unsigned long outval;
 86	unsigned long x;
 87
 88	/*
 89	 * The frequency transfer curve is not linear. The best fit I could
 90	 * get is
 91	 *
 92	 * outval = -155 + exp((f + 15.55) * 0.057))
 93	 *
 94	 * where frequency f is in MHz. Since we don't have exp in the kernel,
 95	 * I approximate this function by a third order polynomial.
 96	 *
 97	 */
 98
 99	x = freq / 160;
100	outval = (x * x + 2500) / 5000;
101	outval = (outval * x + 5000) / 10000;
102	outval -= (10 * x * x + 10433) / 20866;
103	outval += 4 * x - 11505;
104
105	outb_p((outval >> 8) & 0x01, isa->io + 4);
106	outb_p(outval >> 9, isa->io + 6);
107	outb_p(outval & 0xff, isa->io + 8);
108	return 0;
109}
110
111static int typhoon_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
112{
113	struct typhoon *ty = container_of(isa, struct typhoon, isa);
114
115	if (mute)
116		vol = 0;
117	vol >>= 14;			/* Map 16 bit to 2 bit */
118	vol &= 3;
119	outb_p(vol / 2, isa->io);	/* Set the volume, high bit. */
120	outb_p(vol % 2, isa->io + 2);	/* Set the volume, low bit. */
121
122	if (vol == 0 && !ty->muted) {
123		ty->muted = true;
124		return typhoon_s_frequency(isa, mutefreq << 4);
125	}
126	if (vol && ty->muted) {
127		ty->muted = false;
128		return typhoon_s_frequency(isa, isa->freq);
129	}
130	return 0;
131}
132
133static const struct radio_isa_ops typhoon_ops = {
134	.alloc = typhoon_alloc,
135	.s_mute_volume = typhoon_s_mute_volume,
136	.s_frequency = typhoon_s_frequency,
137};
138
139static const int typhoon_ioports[] = { 0x316, 0x336 };
140
141static struct radio_isa_driver typhoon_driver = {
142	.driver = {
143		.match		= radio_isa_match,
144		.probe		= radio_isa_probe,
145		.remove		= radio_isa_remove,
146		.driver		= {
147			.name	= "radio-typhoon",
148		},
149	},
150	.io_params = io,
151	.radio_nr_params = radio_nr,
152	.io_ports = typhoon_ioports,
153	.num_of_io_ports = ARRAY_SIZE(typhoon_ioports),
154	.region_size = 8,
155	.card = "Typhoon Radio",
156	.ops = &typhoon_ops,
157	.has_stereo = true,
158	.max_volume = 3,
159};
160
161static int __init typhoon_init(void)
162{
163	if (mutefreq < 87000 || mutefreq > 108000) {
164		printk(KERN_ERR "%s: You must set a frequency (in kHz) used when muting the card,\n",
165				typhoon_driver.driver.driver.name);
166		printk(KERN_ERR "%s: e.g. with \"mutefreq=87500\" (87000 <= mutefreq <= 108000)\n",
167				typhoon_driver.driver.driver.name);
168		return -ENODEV;
169	}
170	return isa_register_driver(&typhoon_driver.driver, TYPHOON_MAX);
171}
172
173static void __exit typhoon_exit(void)
174{
175	isa_unregister_driver(&typhoon_driver.driver);
176}
177
178
179module_init(typhoon_init);
180module_exit(typhoon_exit);
181