1 files changed, 172 insertions, 7 deletions

diff --git a/firmware/drivers/fmradio_i2c.c b/firmware/drivers/fmradio_i2c.c
index 93c5d2fa91..d503980391 100644
--- a/firmware/drivers/fmradio_i2c.c
+++ b/firmware/drivers/fmradio_i2c.c
@@ -8,7 +8,7 @@
  * $Id$
  * Physical interface of the Philips TEA5767 in Archos Ondio
  *
- * Copyright (C) 2004 by Jörg Hohensohn
+ * Copyright (C) 2002 by Linus Nielsen Feltzing
  *
  * All files in this archive are subject to the GNU General Public License.
  * See the file COPYING in the source tree root for full license agreement.
@@ -26,16 +26,181 @@
 
 #ifdef CONFIG_TUNER
 
-/* reads 5 byte */
-void fmradio_i2c_read(unsigned char* p_data)
+
+/* cute little functions, atomic read-modify-write */
+/* SDA is PB4 */
+#define SDA_LO     and_b(~0x10, &PBDRL)
+#define SDA_HI     or_b(0x10, &PBDRL)
+#define SDA_INPUT  and_b(~0x10, &PBIORL)
+#define SDA_OUTPUT or_b(0x10, &PBIORL)
+#define SDA     (PBDR & 0x0010)
+
+/* SCL is PB1 */
+#define SCL_INPUT  and_b(~0x02, &PBIORL)
+#define SCL_OUTPUT or_b(0x02, &PBIORL)
+#define SCL_LO     and_b(~0x02, &PBDRL)
+#define SCL_HI     or_b(0x02, &PBDRL)
+#define SCL     (PBDR & 0x0002)
+
+/* arbitrary delay loop */
+#define DELAY   do { int _x; for(_x=0;_x<20;_x++);} while (0)
+
+
+static void fmradio_i2c_start(void)
+{
+    SDA_OUTPUT;
+    SDA_HI;
+    SCL_HI;
+    SDA_LO;
+    DELAY;
+    SCL_LO;
+}
+
+static void fmradio_i2c_stop(void)
+{
+   SDA_LO;
+   SCL_HI;
+   DELAY;
+   SDA_HI;
+}
+
+
+static void fmradio_i2c_ack(int bit)
+{
+    /* Here's the deal. The slave is slow, and sometimes needs to wait
+       before it can receive the acknowledge. Therefore it forces the clock
+       low until it is ready. We need to poll the clock line until it goes
+       high before we release the ack. */
+    
+    SCL_LO;      /* Set the clock low */
+    if ( bit )
+    {
+        SDA_HI;
+    }
+    else
+    {
+        SDA_LO;
+    }
+    
+    SCL_INPUT;   /* Set the clock to input */
+    while(!SCL)  /* and wait for the slave to release it */
+        sleep_thread();
+    wake_up_thread();
+
+    DELAY;
+    SCL_OUTPUT;
+    SCL_LO;
+}
+
+static int fmradio_i2c_getack(void)
 {
-    (void)p_data;
+    int ret = 1;
+
+    /* Here's the deal. The slave is slow, and sometimes needs to wait
+       before it can send the acknowledge. Therefore it forces the clock
+       low until it is ready. We need to poll the clock line until it goes
+       high before we read the ack. */
+
+    SDA_INPUT;   /* And set to input */
+    SCL_INPUT;   /* Set the clock to input */
+    while(!SCL)  /* and wait for the slave to release it */
+        sleep_thread();
+    wake_up_thread();
+    
+    if (SDA)
+        /* ack failed */
+        ret = 0;
+    
+    SCL_OUTPUT;
+    SCL_LO;
+    SDA_HI;
+    SDA_OUTPUT;
+    return ret;
+}
+
+static void fmradio_i2c_outb(unsigned char byte)
+{
+   int i;
+
+   /* clock out each bit, MSB first */
+   for ( i=0x80; i; i>>=1 ) {
+      if ( i & byte )
+      {
+         SDA_HI;
+      }
+      else
+      {
+         SDA_LO;
+      }
+      SCL_HI;
+      SCL_LO;
+   }
+
+   SDA_HI;
+}
+
+static unsigned char fmradio_i2c_inb(int ack)
+{
+   int i;
+   unsigned char byte = 0;
+
+   /* clock in each bit, MSB first */
+   for ( i=0x80; i; i>>=1 ) {
+       SDA_INPUT;   /* And set to input */
+       SCL_HI;
+       if ( SDA )
+           byte |= i;
+       SCL_LO;
+       SDA_OUTPUT;
+   }
+   
+   fmradio_i2c_ack(ack);
+   
+   return byte;
+}
+
+int fmradio_i2c_write(int address, const unsigned char* buf, int count)
+{
+    int i,x=0;
+
+    fmradio_i2c_start();
+    fmradio_i2c_outb(address & 0xfe);
+    if (fmradio_i2c_getack())
+    {
+        for (i=0; i<count; i++)
+        {
+            fmradio_i2c_outb(buf[i]);
+            if (!fmradio_i2c_getack())
+            {
+                x=-2;
+                break;
+            }
+        }
+    }
+    else
+    {
+        debugf("fmradio_i2c_write() - no ack\n");
+        x=-1;
+    }
+    fmradio_i2c_stop();
+    return x;
 }
 
-/* writes 5 bytes */
-void fmradio_i2c_set(const unsigned char* p_data)
+int fmradio_i2c_read(int address, unsigned char* buf, int count)
 {
-    (void)p_data;
+    int i,x=0;
+    
+    fmradio_i2c_start();
+    fmradio_i2c_outb(address | 1);
+    if (fmradio_i2c_getack()) {
+        for (i=0; i<count; i++) {
+            buf[i] = fmradio_i2c_inb(0);
+        }
+    }
+    else
+        x=-1;
+    fmradio_i2c_stop();
+    return x;
 }
 
 #endif