File: /usr/src/linux/drivers/media/radio/miropcm20-rds-core.c
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 #define _NO_VERSION_
17
18 /* #include <linux/kernel.h> */
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <asm/semaphore.h>
23 #include <asm/io.h>
24 #include "../../sound/aci.h"
25 #include "miropcm20-rds-core.h"
26
27 #define DEBUG 0
28
29 static struct semaphore aci_rds_sem;
30
31 #define RDS_DATASHIFT 2 /* Bit 2 */
32 #define RDS_DATAMASK (1 << RDS_DATASHIFT)
33 #define RDS_BUSYMASK 0x10 /* Bit 4 */
34 #define RDS_CLOCKMASK 0x08 /* Bit 3 */
35
36 #define RDS_DATA(x) (((x) >> RDS_DATASHIFT) & 1)
37
38
39 #if DEBUG
40 static void print_matrix(char array[], unsigned int length)
41 {
42 int i, j;
43
44 for (i=0; i<length; i++) {
45 printk(KERN_DEBUG "aci-rds: ");
46 for (j=7; j>=0; j--) {
47 printk("%d", (array[i] >> j) & 0x1);
48 }
49 if (i%8 == 0)
50 printk(" byte-border\n");
51 else
52 printk("\n");
53 }
54 }
55 #endif /* DEBUG */
56
57 static int byte2trans(unsigned char byte, unsigned char sendbuffer[], int size)
58 {
59 int i;
60
61 if (size != 8)
62 return -1;
63 for (i = 7; i >= 0; i--)
64 sendbuffer[7-i] = (byte & (1 << i)) ? RDS_DATAMASK : 0;
65 sendbuffer[0] |= RDS_CLOCKMASK;
66
67 return 0;
68 }
69
70 static int rds_waitread(void)
71 {
72 unsigned char byte;
73 int i=2000;
74
75 do {
76 byte=inb(RDS_REGISTER);
77 i--;
78 }
79 while ((byte & RDS_BUSYMASK) && i);
80
81 if (i) {
82 #if DEBUG
83 printk(KERN_DEBUG "rds_waitread()");
84 print_matrix(&byte, 1);
85 #endif
86 return (byte);
87 } else {
88 printk(KERN_WARNING "aci-rds: rds_waitread() timeout...\n");
89 return -1;
90 }
91 }
92
93 /* dont use any ..._nowait() function if you are not sure what you do... */
94
95 static inline void rds_rawwrite_nowait(unsigned char byte)
96 {
97 #if DEBUG
98 printk(KERN_DEBUG "rds_rawwrite()");
99 print_matrix(&byte, 1);
100 #endif
101 outb(byte, RDS_REGISTER);
102 }
103
104 static int rds_rawwrite(unsigned char byte)
105 {
106 if (rds_waitread() >= 0) {
107 rds_rawwrite_nowait(byte);
108 return 0;
109 } else
110 return -1;
111 }
112
113 static int rds_write(unsigned char cmd)
114 {
115 unsigned char sendbuffer[8];
116 int i;
117
118 if (byte2trans(cmd, sendbuffer, 8) != 0){
119 return -1;
120 } else {
121 for (i=0; i<8; i++) {
122 rds_rawwrite(sendbuffer[i]);
123 }
124 }
125 return 0;
126 }
127
128 static int rds_readcycle_nowait(void)
129 {
130 rds_rawwrite_nowait(0);
131 return rds_waitread();
132 }
133
134 static int rds_readcycle(void)
135 {
136 if (rds_rawwrite(0) < 0)
137 return -1;
138 return rds_waitread();
139 }
140
141 static int rds_read(unsigned char databuffer[], int datasize)
142 {
143 #define READSIZE (8*datasize)
144
145 int i,j;
146
147 if (datasize < 1) /* nothing to read */
148 return 0;
149
150 /* to be able to use rds_readcycle_nowait()
151 I have to waitread() here */
152 if (rds_waitread() < 0)
153 return -1;
154
155 memset(databuffer, 0, datasize);
156
157 for (i=0; i< READSIZE; i++)
158 if((j=rds_readcycle_nowait()) < 0) {
159 return -1;
160 } else {
161 databuffer[i/8]|=(RDS_DATA(j) << (7-(i%8)));
162 }
163
164 return 0;
165 }
166
167 static int rds_ack(void)
168 {
169 int i=rds_readcycle();
170
171 if (i < 0)
172 return -1;
173 if (i & RDS_DATAMASK) {
174 return 0; /* ACK */
175 } else {
176 printk(KERN_DEBUG "aci-rds: NACK\n");
177 return 1; /* NACK */
178 }
179 }
180
181 int aci_rds_cmd(unsigned char cmd, unsigned char databuffer[], int datasize)
182 {
183 int ret;
184
185 if (down_interruptible(&aci_rds_sem))
186 return -EINTR;
187
188 rds_write(cmd);
189
190 /* RDS_RESET doesn't need further processing */
191 if (cmd!=RDS_RESET && (rds_ack() || rds_read(databuffer, datasize)))
192 ret = -1;
193 else
194 ret = 0;
195
196 up(&aci_rds_sem);
197
198 return ret;
199 }
200 EXPORT_SYMBOL(aci_rds_cmd);
201
202 int __init attach_aci_rds(void)
203 {
204 init_MUTEX(&aci_rds_sem);
205 return 0;
206 }
207
208 void __exit unload_aci_rds(void)
209 {
210 }
211