diff options
Diffstat (limited to 'drivers/media/radio/miropcm20-rds-core.c')
| -rw-r--r-- | drivers/media/radio/miropcm20-rds-core.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/media/radio/miropcm20-rds-core.c b/drivers/media/radio/miropcm20-rds-core.c new file mode 100644 index 00000000000..a917a90cb5d --- /dev/null +++ b/drivers/media/radio/miropcm20-rds-core.c @@ -0,0 +1,210 @@ +/* + * 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 + */ + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <asm/semaphore.h> +#include <asm/io.h> +#include "../../../sound/oss/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; + } +} + +/* don't 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"); |