rda5802: document some registers

This information is available in the RDA5802N or RDA5807 datasheet. I suspect
that register SYSCONFIG6 is not actually used by the tuner. Based on an
obscure statement in the datasheet, I guess SYSCONFIG5 is a frequency in Khz
called freq_direct that offsets the lower band frequency (56/67 MHz) but
1) it is not enabled (FREQ_MODE=0) and 2) it is not clear if this offset is
really just to avoid interference (ie the RF and IF are simply shifted by this
amount) or an actual offset.

Change-Id: Ia469f5370aee7c8c3390324d0cef1193c64df755

1 files changed, 7 insertions, 7 deletions

diff --git a/firmware/drivers/tuner/rda5802.c b/firmware/drivers/tuner/rda5802.c
index 3f122714bd..55e775e985 100644
--- a/firmware/drivers/tuner/rda5802.c
+++ b/firmware/drivers/tuner/rda5802.c
@@ -48,9 +48,9 @@
 #define SYSCONFIG1  0x4
 #define SYSCONFIG2  0x5
 #define SYSCONFIG3  0x6
-#define SYSCONFIG4  0x7 /* undocumented */
-#define SYSCONFIG5  0x8 /* undocumented */
-#define SYSCONFIG6  0x9 /* undocumented */
+#define SYSCONFIG4  0x7
+#define SYSCONFIG5  0x8
+#define SYSCONFIG6  0x9 /* suspected not to exists */
 #define READCHAN    0xA
 #define STATUSRSSI  0xB
 
@@ -81,7 +81,7 @@
 
 /* SYSCONFIG1 (0x4) */
 #define SYSCONFIG1_DE       (0x1 << 11)
-    #define SYSCONFIG1_SOFTMUTE_EN  (0x1 << 9)
+#define SYSCONFIG1_SOFTMUTE_EN  (0x1 << 9)
 
 /* SYSCONFIG2 (0x5) */
 #define SYSCONFIG2_VOLUME   (0xF <<  0)
@@ -105,9 +105,9 @@ static uint16_t cache[16] = {
     [SYSCONFIG1] =  0x0200, /* SYSCONFIG1_SOFTMUTE_EN */
     [SYSCONFIG2] =  0x867F, /* INT_MODE (def), SEEKTH=1100b, LNA_PORT_SEL=LNAN,
                                LNA_ICSEL=3.0mA, VOLUME=max */
-    [SYSCONFIG3] =  0x8000, /* I2S slave mode */
-    [SYSCONFIG4] =  0x4712, /* undocumented, affects stereo blend */
-    [SYSCONFIG5] =  0x5EC6, /* undocumented */
+    [SYSCONFIG3] =  0x8000, /* RSVD */
+    [SYSCONFIG4] =  0x4712, /* TH_SOFRBLEND=34dB, 65M_50M MODE=65~76MHz, RSVD, SEEK_TH_OLD=4, SOFTBLEND_EN */
+    [SYSCONFIG5] =  0x5EC6, /* FREQ_DIRECT=24262kHz (unused) */
     [SYSCONFIG6] =  0x0000  /* undocumented */
 };