patch-2.4.6 linux/drivers/media/radio/miropcm20-rds-core.c

• Lines: 211
• Date: Tue Jun 12 10:56:11 2001
• Orig file: v2.4.5/linux/drivers/media/radio/miropcm20-rds-core.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.5/linux/drivers/media/radio/miropcm20-rds-core.c linux/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
+ */
+
+#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)
+{
+}