Viewing file:  miropcm20-rds-core.c (4.01 KB) -rw-r--r--
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/*
* Many thanks to Fred Seidel <seidel@metabox.de>, the
* designer of the RDS decoder hardware. With his help
* I was able to code this driver.
* Thanks also to Norberto Pellicci, Dominic Mounteney
* <DMounteney@pinnaclesys.com> and www.teleauskunft.de
* for good hints on finding Fred. It was somewhat hard
* to locate him here in Germany... [:
*
* Revision history:
*
* 2000-08-09 Robert Siemer <Robert.Siemer@gmx.de>
* RDS support for MiroSound PCM20 radio
*/
#define _NO_VERSION_
/* #include <linux/kernel.h> */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <asm/semaphore.h>
#include <asm/io.h>
#include "../../sound/aci.h"
#include "miropcm20-rds-core.h"
#define DEBUG 0
static struct semaphore aci_rds_sem;
#define RDS_DATASHIFT 2 /* Bit 2 */
#define RDS_DATAMASK (1 << RDS_DATASHIFT)
#define RDS_BUSYMASK 0x10 /* Bit 4 */
#define RDS_CLOCKMASK 0x08 /* Bit 3 */
#define RDS_DATA(x) (((x) >> RDS_DATASHIFT) & 1)
#if DEBUG
static void print_matrix(char array[], unsigned int length)
{
int i, j;
for (i=0; i<length; i++) {
printk(KERN_DEBUG "aci-rds: ");
for (j=7; j>=0; j--) {
printk("%d", (array[i] >> j) & 0x1);
}
if (i%8 == 0)
printk(" byte-border\n");
else
printk("\n");
}
}
#endif /* DEBUG */
static int byte2trans(unsigned char byte, unsigned char sendbuffer[], int size)
{
int i;
if (size != 8)
return -1;
for (i = 7; i >= 0; i--)
sendbuffer[7-i] = (byte & (1 << i)) ? RDS_DATAMASK : 0;
sendbuffer[0] |= RDS_CLOCKMASK;
return 0;
}
static int rds_waitread(void)
{
unsigned char byte;
int i=2000;
do {
byte=inb(RDS_REGISTER);
i--;
}
while ((byte & RDS_BUSYMASK) && i);
if (i) {
#if DEBUG
printk(KERN_DEBUG "rds_waitread()");
print_matrix(&byte, 1);
#endif
return (byte);
} else {
printk(KERN_WARNING "aci-rds: rds_waitread() timeout...\n");
return -1;
}
}
/* dont use any ..._nowait() function if you are not sure what you do... */
static inline void rds_rawwrite_nowait(unsigned char byte)
{
#if DEBUG
printk(KERN_DEBUG "rds_rawwrite()");
print_matrix(&byte, 1);
#endif
outb(byte, RDS_REGISTER);
}
static int rds_rawwrite(unsigned char byte)
{
if (rds_waitread() >= 0) {
rds_rawwrite_nowait(byte);
return 0;
} else
return -1;
}
static int rds_write(unsigned char cmd)
{
unsigned char sendbuffer[8];
int i;
if (byte2trans(cmd, sendbuffer, 8) != 0){
return -1;
} else {
for (i=0; i<8; i++) {
rds_rawwrite(sendbuffer[i]);
}
}
return 0;
}
static int rds_readcycle_nowait(void)
{
rds_rawwrite_nowait(0);
return rds_waitread();
}
static int rds_readcycle(void)
{
if (rds_rawwrite(0) < 0)
return -1;
return rds_waitread();
}
static int rds_read(unsigned char databuffer[], int datasize)
{
#define READSIZE (8*datasize)
int i,j;
if (datasize < 1) /* nothing to read */
return 0;
/* to be able to use rds_readcycle_nowait()
I have to waitread() here */
if (rds_waitread() < 0)
return -1;
memset(databuffer, 0, datasize);
for (i=0; i< READSIZE; i++)
if((j=rds_readcycle_nowait()) < 0) {
return -1;
} else {
databuffer[i/8]|=(RDS_DATA(j) << (7-(i%8)));
}
return 0;
}
static int rds_ack(void)
{
int i=rds_readcycle();
if (i < 0)
return -1;
if (i & RDS_DATAMASK) {
return 0; /* ACK */
} else {
printk(KERN_DEBUG "aci-rds: NACK\n");
return 1; /* NACK */
}
}
int aci_rds_cmd(unsigned char cmd, unsigned char databuffer[], int datasize)
{
int ret;
if (down_interruptible(&aci_rds_sem))
return -EINTR;
rds_write(cmd);
/* RDS_RESET doesn't need further processing */
if (cmd!=RDS_RESET && (rds_ack() || rds_read(databuffer, datasize)))
ret = -1;
else
ret = 0;
up(&aci_rds_sem);
return ret;
}
EXPORT_SYMBOL(aci_rds_cmd);
int __init attach_aci_rds(void)
{
init_MUTEX(&aci_rds_sem);
return 0;
}
void __exit unload_aci_rds(void)
{
}
MODULE_LICENSE("GPL");
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