Add video Pre-ADC gain setting

software/sys_controller/tvp7002/tvp7002.c

@@ -151,6 +151,7 @@ void tvp_init()
         .r_f_off = DEFAULT_FINE_OFFSET,
         .g_f_off = DEFAULT_FINE_OFFSET,
         .b_f_off = DEFAULT_FINE_OFFSET,
+        .c_gain = DEFAULT_COARSE_GAIN,
     };
 
     // disable output
@@ -201,20 +202,20 @@ void tvp_init()
     tvp_set_hpllcoast(DEFAULT_PRE_COAST, DEFAULT_POST_COAST);
 
     //set analog (coarse) gain to max recommended value (-> 91% of the ADC range with 0.7Vpp input)
-    tvp_writereg(TVP_BG_CGAIN, 0x88);
-    tvp_writereg(TVP_R_CGAIN, 0x08);
-
     //set rest of the gain digitally (fine) to utilize 100% of the range at the output (0.91*(1+(26/256)) = 1)
-    tvp_set_fine_gain_offset(&def_gain_offs);
+    tvp_set_gain_offset(&def_gain_offs);
 }
 
-void tvp_set_fine_gain_offset(color_setup_t *col) {
+void tvp_set_gain_offset(color_setup_t *col) {
+    tvp_writereg(TVP_BG_CGAIN, ((col->c_gain << 4) | (col->c_gain & 0xF)));
+    tvp_writereg(TVP_R_CGAIN, col->c_gain);
     tvp_writereg(TVP_R_FGAIN, col->r_f_gain);
     tvp_writereg(TVP_G_FGAIN, col->g_f_gain);
     tvp_writereg(TVP_B_FGAIN, col->b_f_gain);
     tvp_writereg(TVP_R_FOFFSET_MSB, col->r_f_off);
     tvp_writereg(TVP_G_FOFFSET_MSB, col->g_f_off);
     tvp_writereg(TVP_B_FOFFSET_MSB, col->b_f_off);
+
 }
 
 // Configure H-PLL (sampling rate, VCO gain and charge pump current)

software/sys_controller/tvp7002/tvp7002.h

@@ -33,6 +33,7 @@
 #define DEFAULT_SYNC_VTH        0x0B
 #define DEFAULT_FINE_GAIN       26
 #define DEFAULT_FINE_OFFSET     0x80
+#define DEFAULT_COARSE_GAIN     0x8
 
 #define TVP_INTCLK_HZ           6500000UL
 #define TVP_EXTCLK_HZ           27000000UL
@@ -68,6 +69,7 @@ typedef struct {
     alt_u8 r_f_gain;
     alt_u8 g_f_gain;
     alt_u8 b_f_gain;
+    alt_u8 c_gain;
 } __attribute__((packed)) color_setup_t;
 
 
@@ -89,7 +91,7 @@ inline void tvp_set_ssthold(alt_u8 vsdetect_thold);
 
 void tvp_init();
 
-void tvp_set_fine_gain_offset(color_setup_t *col);
+void tvp_set_gain_offset(color_setup_t *col);
 
 void tvp_setup_hpll(alt_u16 h_samplerate, alt_u16 refclks_per_line, alt_u8 plldivby2);