V4L/DVB (11865): cx18: Tweak color burst gate delay and initial color sub-carrier freq

Fix the burst gate delays to use a crystal value of 28636360 as assumed by
the rest of the driver.  Also have the initial color sub-carrier freq paramter
use the src decimation ratio per the documentation, instead of the actual
crystal/pixel clock ratio.  The tracking circuit will find the correct color
subcarrier in any case, as long as we're close.  Also fix up some debug print
statements.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 48 insertions, 21 deletions

diff --git a/drivers/media/video/cx18/cx18-av-core.c b/drivers/media/video/cx18/cx18-av-core.c
index 33ec269a0f5e..0b3d840cc2e2 100644
--- a/drivers/media/video/cx18/cx18-av-core.c
+++ b/drivers/media/video/cx18/cx18-av-core.c
@@ -277,8 +277,15 @@ void cx18_av_std_setup(struct cx18 *cx)
         struct cx18_av_state *state = &cx->av_state;
         struct v4l2_subdev *sd = &state->sd;
         v4l2_std_id std = state->std;
+
+        /*
+         * Video ADC crystal clock to pixel clock SRC decimation ratio
+         * 28.636360 MHz/13.5 Mpps * 256 = 0x21f.07b
+         */
+        const int src_decimation = 0x21f;
+
         int hblank, hactive, burst, vblank, vactive, sc;
-        int vblank656, src_decimation;
+        int vblank656;
         int luma_lpf, uv_lpf, comb;
         u32 pll_int, pll_frac, pll_post;
 
@@ -342,21 +349,31 @@ void cx18_av_std_setup(struct cx18 *cx)
                 hblank = 132;
                 hactive = 720;
 
+                /*
+                 * Burst gate delay (for 625 line systems)
+                 * Hsync leading edge to color burst rise = 5.6 us
+                 * Color burst width = 2.25 us
+                 * Gate width = 4 pixel clocks
+                 * (5.6 us + 2.25/2 us) * 13.5 Mpps + 4/2 clocks = 92.79 clocks
+                 */
                 burst = 93;
                 luma_lpf = 2;
-                src_decimation = 0x21f;
                 if (std & V4L2_STD_PAL) {
                         uv_lpf = 1;
                         comb = 0x20;
-                        sc = 688739;
+                        /* sc = 4433618.75 * src_decimation/28636360 * 2^13 */
+                        sc = 688700;
                 } else if (std == V4L2_STD_PAL_Nc) {
                         uv_lpf = 1;
                         comb = 0x20;
-                        sc = 556453;
+                        /* sc = 3582056.25 * src_decimation/28636360 * 2^13 */
+                        sc = 556422;
                 } else { /* SECAM */
                         uv_lpf = 0;
                         comb = 0;
-                        sc = 672351;
+                        /* (fr + fb)/2 = (4406260 + 4250000)/2 = 4328130 */
+                        /* sc = 4328130 * src_decimation/28636360 * 2^13 */
+                        sc = 672314;
                 }
         } else {
                 /*
@@ -394,20 +411,30 @@ void cx18_av_std_setup(struct cx18 *cx)
                 luma_lpf = 1;
                 uv_lpf = 1;
 
-                src_decimation = 0x21f;
+                /*
+                 * Burst gate delay (for 525 line systems)
+                 * Hsync leading edge to color burst rise = 5.3 us
+                 * Color burst width = 2.5 us
+                 * Gate width = 4 pixel clocks
+                 * (5.3 us + 2.5/2 us) * 13.5 Mpps + 4/2 clocks = 90.425 clocks
+                 */
                 if (std == V4L2_STD_PAL_60) {
-                        burst = 0x5b;
+                        burst = 90;
                         luma_lpf = 2;
                         comb = 0x20;
-                        sc = 688739;
+                        /* sc = 4433618.75 * src_decimation/28636360 * 2^13 */
+                        sc = 688700;
                 } else if (std == V4L2_STD_PAL_M) {
-                        burst = 0x61;
+                        /* The 97 needs to be verified against PAL-M timings */
+                        burst = 97;
                         comb = 0x20;
-                        sc = 555452;
+                        /* sc = 3575611.49 * src_decimation/28636360 * 2^13 */
+                        sc = 555421;
                 } else {
-                        burst = 0x5b;
+                        burst = 90;
                         comb = 0x66;
-                        sc = 556063;
+                        /* sc = 3579545.45.. * src_decimation/28636360 * 2^13 */
+                        sc = 556032;
                 }
         }
 
@@ -419,23 +446,23 @@ void cx18_av_std_setup(struct cx18 *cx)
                             pll_int, pll_frac, pll_post);
 
         if (pll_post) {
-                int fin, fsc, pll;
+                int fsc, pll;
 
                 pll = (28636360L * ((((u64)pll_int) << 25) + pll_frac)) >> 25;
                 pll /= pll_post;
-                CX18_DEBUG_INFO_DEV(sd, "PLL = %d.%06d MHz\n",
+                CX18_DEBUG_INFO_DEV(sd, "Video PLL = %d.%06d MHz\n",
                                     pll / 1000000, pll % 1000000);
-                CX18_DEBUG_INFO_DEV(sd, "PLL/8 = %d.%06d MHz\n",
+                CX18_DEBUG_INFO_DEV(sd, "Pixel rate = %d.%06d Mpixel/sec\n",
                                     pll / 8000000, (pll / 8) % 1000000);
 
-                fin = ((u64)src_decimation * pll) >> 12;
-                CX18_DEBUG_INFO_DEV(sd, "ADC Sampling freq = %d.%06d MHz\n",
-                                    fin / 1000000, fin % 1000000);
+                CX18_DEBUG_INFO_DEV(sd, "ADC XTAL/pixel clock decimation ratio "
+                                    "= %d.%03d\n", src_decimation / 256,
+                                    ((src_decimation % 256) * 1000) / 256);
 
-                fsc = (((u64)sc) * pll) >> 24L;
+                fsc = ((((u64)sc) * 28636360)/src_decimation) >> 13L;
                 CX18_DEBUG_INFO_DEV(sd,
-                                    "Chroma sub-carrier freq = %d.%06d MHz\n",
-                                    fsc / 1000000, fsc % 1000000);
+                                    "Chroma sub-carrier initial freq = %d.%06d "
+                                    "MHz\n", fsc / 1000000, fsc % 1000000);
 
                 CX18_DEBUG_INFO_DEV(sd, "hblank %i, hactive %i, vblank %i, "
                                     "vactive %i, vblank656 %i, src_dec %i, "