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

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;
 }