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authorMarcoen Hirschberg <marcoen@gmail.com>2007-05-11 16:42:53 +0000
committerMarcoen Hirschberg <marcoen@gmail.com>2007-05-11 16:42:53 +0000
commit685001f0d41c84ed123b8946b45397bf4e8a097e (patch)
tree4d53be7e5b3126784d163fd266c8addcc56ba7c0 /firmware
parentd92e09556fdec3fbd65e153c6f41c31cb1e04c42 (diff)
downloadrockbox-685001f0d41c84ed123b8946b45397bf4e8a097e.tar.gz
rockbox-685001f0d41c84ed123b8946b45397bf4e8a097e.zip
revert the last changes because they prevent some Gigabeats from shutting down
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13372 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware')
-rw-r--r--firmware/target/arm/s3c2440/gigabeat-fx/sc606-meg-fx.c201
1 files changed, 111 insertions, 90 deletions
diff --git a/firmware/target/arm/s3c2440/gigabeat-fx/sc606-meg-fx.c b/firmware/target/arm/s3c2440/gigabeat-fx/sc606-meg-fx.c
index c207e310d9..e69eab432a 100644
--- a/firmware/target/arm/s3c2440/gigabeat-fx/sc606-meg-fx.c
+++ b/firmware/target/arm/s3c2440/gigabeat-fx/sc606-meg-fx.c
@@ -1,5 +1,6 @@
#include "config.h"
#include "cpu.h"
+#include <stdbool.h>
#include "kernel.h"
#include "system.h"
#include "logf.h"
@@ -8,132 +9,147 @@
#define SLAVE_ADDRESS 0xCC
-#define USE_ASM
-
-/* This I2C driver tristates the outputs instead of driving logic high's */
+#define SDA_LO (GPHDAT &= ~(1 << 9))
+#define SDA_HI (GPHDAT |= (1 << 9))
+#define SDA_INPUT (GPHCON &= ~(3 << 18))
+#define SDA_OUTPUT (GPHCON |= (1 << 18))
#define SDA (GPHDAT & (1 << 9))
-#define SDA_LO_OUT (GPHCON |= (1 << 18));(GPHDAT &= ~(1 << 9));
-#define SDA_HI_IN (GPHCON &= ~(3 << 18))
+#define SCL_LO (GPHDAT &= ~(1 << 10))
+#define SCL_HI (GPHDAT |= (1 << 10))
+#define SCL_INPUT (GPHCON &= ~(3 << 20))
+#define SCL_OUTPUT (GPHCON |= (1 << 20))
#define SCL (GPHDAT & (1 << 10))
-#define SCL_LO_OUT (GPHCON |= (1 << 20));(GPHDAT &= ~(1 << 10));
-#define SCL_HI_IN (GPHCON &= ~(3 << 20));while(!SCL);
-
-/* The SC606 can clock at 400KHz:
- * Clock period high is 600nS and low is 1300nS
- * The high and low times are different enough to need different timings
- * cycles delayed = 2 + 4 * loops
- * 100MHz = 10nS per cycle: LO:1300nS=130:33 HI:600nS=60:15
- * 300MHz = 3.33nS per cycle:
- * LO:1300nS=394:99
- * HI:600nS=182:21
- * MID(50/50):950(1900/2)ns=288:72
- */
-
-#ifdef USE_ASM
-
-#define DELAY_LO 99
-#define DELAY_MID 72
-#define DELAY_HI 46
-/* This delay loop takes 4 cycles/loop to execute plus 2 for setup */
-#define DELAY(dly) \
- asm volatile( "mov r0,%0 \n" \
- "1: \n" \
- "subs r0,r0,#1 \n" \
- "bhi 1b \n" \
- : : "r"((dly)) : "r0" );
-
-#else
-
-#define DELAY_LO 51
-#define DELAY_MID 35
-#define DELAY_HI 21
-#define DELAY(dly) do{int x;for(x=(dly);x;x--);} while (0)
-
-#endif
+
+#define SCL_SDA_HI (GPHDAT |= (3 << 9))
+
+/* The SC606 can clock at 400KHz: */
+/* Clock period high is 600nS and low is 1300nS */
+/* The high and low times are different enough to need different timings */
+/* cycles delayed = 30 + 7 * loops */
+/* 100MHz = 10nS per cycle: LO:1300nS=130:14 HI:600nS=60:9 */
+/* 300MHz = 3.36nS per cycle: LO:1300nS=387:51 HI:600nS=179:21 */
+#define DELAY_LO do{int x;for(x=51;x;x--);} while (0)
+#define DELAY do{int x;for(x=35;x;x--);} while (0)
+#define DELAY_HI do{int x;for(x=21;x;x--);} while (0)
+
+
static void sc606_i2c_start(void)
{
- SDA_HI_IN;
- SCL_HI_IN;
- DELAY(DELAY_MID);
- SDA_LO_OUT;
- DELAY(DELAY_MID);
- SCL_LO_OUT;
+ SCL_SDA_HI;
+ DELAY;
+ SDA_LO;
+ DELAY;
+ SCL_LO;
+}
+
+static void sc606_i2c_restart(void)
+{
+ SCL_SDA_HI;
+ DELAY;
+ SDA_LO;
+ DELAY;
+ SCL_LO;
}
static void sc606_i2c_stop(void)
{
- SDA_LO_OUT;
- SCL_HI_IN;
- DELAY(DELAY_HI);
- SDA_HI_IN;
+ SDA_LO;
+ SCL_HI;
+ DELAY_HI;
+ SDA_HI;
}
static void sc606_i2c_ack(void)
{
- SDA_HI_IN;
- SCL_HI_IN;
- DELAY(DELAY_HI);
- SCL_LO_OUT;
+ SDA_LO;
+ SCL_HI;
+ DELAY_HI;
+ SCL_LO;
}
-static bool sc606_i2c_getack(void)
+
+
+static int sc606_i2c_getack(void)
{
- bool ret;
+ int ret;
+
+ /* Don't need a delay since follows a data bit with a delay on the end */
+ SDA_INPUT; /* And set to input */
+ DELAY;
+ SCL_HI;
- SDA_HI_IN;
- DELAY(DELAY_MID);
- SCL_HI_IN;
+ ret = (SDA != 0); /* ack failed if SDA is not low */
+ DELAY_HI;
- ret = !SDA;
+ SCL_LO;
+ DELAY_LO;
- SCL_LO_OUT;
- DELAY(DELAY_LO);
+ SDA_HI;
+ SDA_OUTPUT;
+ DELAY_LO;
return ret;
}
+
+
static void sc606_i2c_outb(unsigned char byte)
{
int i;
/* clock out each bit, MSB first */
- for ( i=0x80; i; i>>=1 )
+ for (i = 0x80; i; i >>= 1)
{
- if ( i & byte )
- SDA_HI_IN;
+ if (i & byte)
+ {
+ SDA_HI;
+ }
else
- SDA_LO_OUT;
- DELAY(DELAY_MID);
- SCL_HI_IN;
- DELAY(DELAY_HI);
- SCL_LO_OUT;
+ {
+ SDA_LO;
+ }
+ DELAY;
+
+ SCL_HI;
+ DELAY_HI;
+
+ SCL_LO;
+ DELAY_LO;
}
+
+ SDA_HI;
+
}
+
+
static unsigned char sc606_i2c_inb(void)
{
- int i;
- unsigned char byte = 0;
+ int i;
+ unsigned char byte = 0;
- /* clock in each bit, MSB first */
- SDA_HI_IN;
- for ( i=0x80; i; i>>=1 )
- {
- SCL_HI_IN;
- DELAY(DELAY_HI);
- if ( SDA )
- byte |= i;
- SCL_LO_OUT;
- DELAY(DELAY_LO);
- }
+ SDA_INPUT; /* And set to input */
+ /* clock in each bit, MSB first */
+ for (i = 0x80; i; i >>= 1) {
+ SCL_HI;
+
+ if (SDA)
+ byte |= i;
- sc606_i2c_ack();
- return byte;
+ SCL_LO;
+ }
+ SDA_OUTPUT;
+
+ sc606_i2c_ack();
+
+ return byte;
}
+
+
/* returns number of acks that were bad */
int sc606_write(unsigned char reg, unsigned char data)
{
@@ -147,7 +163,7 @@ int sc606_write(unsigned char reg, unsigned char data)
sc606_i2c_outb(reg);
x += sc606_i2c_getack();
- sc606_i2c_start();
+ sc606_i2c_restart();
sc606_i2c_outb(SLAVE_ADDRESS);
x += sc606_i2c_getack();
@@ -160,6 +176,8 @@ int sc606_write(unsigned char reg, unsigned char data)
return x;
}
+
+
int sc606_read(unsigned char reg, unsigned char* data)
{
int x;
@@ -171,7 +189,7 @@ int sc606_read(unsigned char reg, unsigned char* data)
sc606_i2c_outb(reg);
x += sc606_i2c_getack();
- sc606_i2c_start();
+ sc606_i2c_restart();
sc606_i2c_outb(SLAVE_ADDRESS | 1);
x += sc606_i2c_getack();
@@ -181,6 +199,8 @@ int sc606_read(unsigned char reg, unsigned char* data)
return x;
}
+
+
void sc606_init(void)
{
volatile int i;
@@ -194,11 +214,12 @@ void sc606_init(void)
/* About 400us - needs 350us */
for (i = 200; i; i--)
- DELAY(DELAY_LO);
+ {
+ DELAY_LO;
+ }
/* Set GPH9 (SDA) and GPH10 (SCL) to 1 */
GPHUP &= ~(3<<9);
- SCL_HI_IN;
- SDA_HI_IN;
+ GPHCON = (GPHCON & ~(0xF<<18)) | 5<<18;
}