tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Many thanks to Fred Seidel <seidel@metabox.de>, the
3 * designer of the RDS decoder hardware. With his help
4 * I was able to code this driver.
5 * Thanks also to Norberto Pellicci, Dominic Mounteney
6 * <DMounteney@pinnaclesys.com> and www.teleauskunft.de
7 * for good hints on finding Fred. It was somewhat hard
8 * to locate him here in Germany... [:
9 *
10 * Revision history:
11 *
12 * 2000-08-09 Robert Siemer <Robert.Siemer@gmx.de>
13 * RDS support for MiroSound PCM20 radio
14 */
15
16#include <linux/module.h>
17#include <linux/errno.h>
18#include <linux/string.h>
19#include <linux/init.h>
20#include <linux/slab.h>
21#include <asm/semaphore.h>
22#include <asm/io.h>
23#include "../../../sound/oss/aci.h"
24#include "miropcm20-rds-core.h"
25
26#define DEBUG 0
27
28static struct semaphore aci_rds_sem;
29
30#define RDS_DATASHIFT 2 /* Bit 2 */
31#define RDS_DATAMASK (1 << RDS_DATASHIFT)
32#define RDS_BUSYMASK 0x10 /* Bit 4 */
33#define RDS_CLOCKMASK 0x08 /* Bit 3 */
34
35#define RDS_DATA(x) (((x) >> RDS_DATASHIFT) & 1)
36
37
38#if DEBUG
39static void print_matrix(char array[], unsigned int length)
40{
41 int i, j;
42
43 for (i=0; i<length; i++) {
44 printk(KERN_DEBUG "aci-rds: ");
45 for (j=7; j>=0; j--) {
46 printk("%d", (array[i] >> j) & 0x1);
47 }
48 if (i%8 == 0)
49 printk(" byte-border\n");
50 else
51 printk("\n");
52 }
53}
54#endif /* DEBUG */
55
56static int byte2trans(unsigned char byte, unsigned char sendbuffer[], int size)
57{
58 int i;
59
60 if (size != 8)
61 return -1;
62 for (i = 7; i >= 0; i--)
63 sendbuffer[7-i] = (byte & (1 << i)) ? RDS_DATAMASK : 0;
64 sendbuffer[0] |= RDS_CLOCKMASK;
65
66 return 0;
67}
68
69static int rds_waitread(void)
70{
71 unsigned char byte;
72 int i=2000;
73
74 do {
75 byte=inb(RDS_REGISTER);
76 i--;
77 }
78 while ((byte & RDS_BUSYMASK) && i);
79
80 if (i) {
81 #if DEBUG
82 printk(KERN_DEBUG "rds_waitread()");
83 print_matrix(&byte, 1);
84 #endif
85 return (byte);
86 } else {
87 printk(KERN_WARNING "aci-rds: rds_waitread() timeout...\n");
88 return -1;
89 }
90}
91
92/* don't use any ..._nowait() function if you are not sure what you do... */
93
94static inline void rds_rawwrite_nowait(unsigned char byte)
95{
96 #if DEBUG
97 printk(KERN_DEBUG "rds_rawwrite()");
98 print_matrix(&byte, 1);
99 #endif
100 outb(byte, RDS_REGISTER);
101}
102
103static int rds_rawwrite(unsigned char byte)
104{
105 if (rds_waitread() >= 0) {
106 rds_rawwrite_nowait(byte);
107 return 0;
108 } else
109 return -1;
110}
111
112static int rds_write(unsigned char cmd)
113{
114 unsigned char sendbuffer[8];
115 int i;
116
117 if (byte2trans(cmd, sendbuffer, 8) != 0){
118 return -1;
119 } else {
120 for (i=0; i<8; i++) {
121 rds_rawwrite(sendbuffer[i]);
122 }
123 }
124 return 0;
125}
126
127static int rds_readcycle_nowait(void)
128{
129 rds_rawwrite_nowait(0);
130 return rds_waitread();
131}
132
133static int rds_readcycle(void)
134{
135 if (rds_rawwrite(0) < 0)
136 return -1;
137 return rds_waitread();
138}
139
140static int rds_read(unsigned char databuffer[], int datasize)
141{
142 #define READSIZE (8*datasize)
143
144 int i,j;
145
146 if (datasize < 1) /* nothing to read */
147 return 0;
148
149 /* to be able to use rds_readcycle_nowait()
150 I have to waitread() here */
151 if (rds_waitread() < 0)
152 return -1;
153
154 memset(databuffer, 0, datasize);
155
156 for (i=0; i< READSIZE; i++)
157 if((j=rds_readcycle_nowait()) < 0) {
158 return -1;
159 } else {
160 databuffer[i/8]|=(RDS_DATA(j) << (7-(i%8)));
161 }
162
163 return 0;
164}
165
166static int rds_ack(void)
167{
168 int i=rds_readcycle();
169
170 if (i < 0)
171 return -1;
172 if (i & RDS_DATAMASK) {
173 return 0; /* ACK */
174 } else {
175 printk(KERN_DEBUG "aci-rds: NACK\n");
176 return 1; /* NACK */
177 }
178}
179
180int aci_rds_cmd(unsigned char cmd, unsigned char databuffer[], int datasize)
181{
182 int ret;
183
184 if (down_interruptible(&aci_rds_sem))
185 return -EINTR;
186
187 rds_write(cmd);
188
189 /* RDS_RESET doesn't need further processing */
190 if (cmd!=RDS_RESET && (rds_ack() || rds_read(databuffer, datasize)))
191 ret = -1;
192 else
193 ret = 0;
194
195 up(&aci_rds_sem);
196
197 return ret;
198}
199EXPORT_SYMBOL(aci_rds_cmd);
200
201int __init attach_aci_rds(void)
202{
203 init_MUTEX(&aci_rds_sem);
204 return 0;
205}
206
207void __exit unload_aci_rds(void)
208{
209}
210MODULE_LICENSE("GPL");