tea5767 detection

Index: firmware/export/tea5767.h
===================================================================
--- firmware/export/tea5767.h	(revision 28449)
+++ firmware/export/tea5767.h	(working copy)
@@ -32,6 +32,7 @@
     unsigned char write_regs[5];
 };
 
+void tea5767_init(void);
 int tea5767_set(int setting, int value);
 int tea5767_get(int setting);
 void tea5767_dbg_info(struct tea5767_dbg_info *info);
Index: firmware/drivers/tuner/tea5767.c
===================================================================
--- firmware/drivers/tuner/tea5767.c	(revision 28449)
+++ firmware/drivers/tuner/tea5767.c	(working copy)
@@ -34,6 +34,7 @@
 #define I2C_ADR 0xC0
 #endif
 
+static bool tuner_present = false;
 static unsigned char write_bytes[5] = { 0x00, 0x00, 0x00, 0x00, 0x00 };
 
 static void tea5767_set_clear(int byte, unsigned char bits, int set)
@@ -116,7 +117,7 @@
     switch(setting)
     {
         case RADIO_PRESENT:
-            val = 1; /* true */
+            val = tuner_present ? 1 : 0;
             break;
 
         case RADIO_TUNED:
@@ -136,6 +137,24 @@
     return val;
 }
 
+void tea5767_init(void)
+{
+    unsigned char buf[5];
+    unsigned char chipid;
+
+    /* read all registers */
+    if (fmradio_i2c_read(I2C_ADR, buf, sizeof(buf)) < 0) {
+        /* no i2c device detected */
+        return;
+    }
+    
+    /* check device id */
+    chipid = (buf[3] >> 1) & 7;
+    if (chipid == 0) {
+        tuner_present = true;
+    }
+}
+
 void tea5767_dbg_info(struct tea5767_dbg_info *info)
 {
     fmradio_i2c_read(I2C_ADR, info->read_regs, 5);
Index: firmware/tuner.c
===================================================================
--- firmware/tuner.c	(revision 28449)
+++ firmware/tuner.c	(working copy)
@@ -74,7 +74,8 @@
     #if (CONFIG_TUNER & TEA5767)
         TUNER_TYPE_CASE(TEA5767,
                         tea5767_set,
-                        tea5767_get)
+                        tea5767_get,
+                        tea5767_init())
     #endif
     #if (CONFIG_TUNER & S1A0903X01)
         TUNER_TYPE_CASE(S1A0903X01,