V4L/DVB (11863): cx18: Initial attempt to get sliced VBI working for 625 line systems

Initial changes to get sliced VBI for 625 line system working.  This is patch
is untested.

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

3 files changed, 56 insertions, 15 deletions

diff --git a/drivers/media/video/cx18/cx18-av-core.c b/drivers/media/video/cx18/cx18-av-core.c
index 2b07b156340b..d98010e0da9c 100644
--- a/drivers/media/video/cx18/cx18-av-core.c
+++ b/drivers/media/video/cx18/cx18-av-core.c
@@ -288,17 +288,52 @@ void cx18_av_std_setup(struct cx18 *cx)
         else
                 cx18_av_write(cx, 0x49f, 0x14);
 
+        /*
+         * Note: At the end of a field, there are 3 sets of half line duration
+         * (double horizontal rate) pulses:
+         *
+         * 5 (625) or 6 (525) half-lines to blank for the vertical retrace
+         * 5 (625) or 6 (525) vertical sync pulses of half line duration
+         * 5 (625) or 6 (525) half-lines of equalization pulses
+         */
         if (std & V4L2_STD_625_50) {
-                /* FIXME - revisit these for Sliced VBI */
+                /*
+                 * The following relationships of half line counts should hold:
+                 * 625 = vblank656 + vactive + postvactive
+                 * 10 = vblank656 - vblank = vsync pulses + equalization pulses
+                 *
+                 * vblank656: half lines after line 625/mid-313 of blanked video
+                 * vblank:    half lines, after line 5/317, of blanked video
+                 * vactive:   half lines of active video
+                 * postvactive: 5 half lines after the end of active video
+                 *
+                 * As far as I can tell:
+                 * vblank656 starts counting from the falling edge of the first
+                 *      vsync pulse (start of line 1 or mid-313)
+                 * vblank starts counting from the after the 5 vsync pulses and
+                 *      5 or 4 equalization pulses (start of line 6 or 318)
+                 *
+                 * For 625 line systems the driver will extract VBI information
+                 * from lines 6-23 and lines 318-335 (but the slicer can only
+                 * handle 17 lines, not the 18 in the vblank region).
+                 */
+                vblank656 = 46; /* lines  1 -  23  &  313 - 335 */
+                vblank = 36;    /* lines  6 -  23  &  318 - 335 */
+                vactive = 574;  /* lines 24 - 310  &  336 - 622 */
+
+                /*
+                 * For a 13.5 Mpps clock and 15,625 Hz line rate, a line is
+                 * is 864 pixels = 720 active + 144 blanking.  ITU-R BT.601
+                 * specifies 12 luma clock periods or ~ 0.9 * 13.5 Mpps after
+                 * the end of active video to start a horizontal line, so that
+                 * leaves 132 pixels of hblank to ignore.
+                 */
                 hblank = 132;
                 hactive = 720;
-                burst = 93;
-                vblank = 36;
-                vactive = 580;
-                vblank656 = 40;
-                src_decimation = 0x21f;
 
+                burst = 93;
                 luma_lpf = 2;
+                src_decimation = 0x21f;
                 if (std & V4L2_STD_PAL) {
                         uv_lpf = 1;
                         comb = 0x20;
@@ -315,13 +350,13 @@ void cx18_av_std_setup(struct cx18 *cx)
         } else {
                 /*
                  * The following relationships of half line counts should hold:
-                 * 525 = vsync + vactive + vblank656
-                 * 12 = vblank656 - vblank
+                 * 525 = prevsync + vblank656 + vactive
+                 * 12 = vblank656 - vblank = vsync pulses + equalization pulses
                  *
-                 * vsync:     always 6 half-lines of vsync pulses
-                 * vactive:   half lines of active video
+                 * prevsync:  6 half-lines before the vsync pulses
                  * vblank656: half lines, after line 3/mid-266, of blanked video
                  * vblank:    half lines, after line 9/272, of blanked video
+                 * vactive:   half lines of active video
                  *
                  * As far as I can tell:
                  * vblank656 starts counting from the falling edge of the first
@@ -954,9 +989,9 @@ static int cx18_av_s_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt)
                  * cx18_av_std_setup(), above standard values:
                  *
                  * 480 + 1 for 60 Hz systems
-                 * 576 + 4 for 50 Hz systems
+                 * 576 - 2 for 50 Hz systems
                  */
-                Vlines = pix->height + (is_50Hz ? 4 : 1);
+                Vlines = pix->height + (is_50Hz ? -2 : 1);
 
                 /*
                  * Invalid height and width scaling requests are:
diff --git a/drivers/media/video/cx18/cx18-av-vbi.c b/drivers/media/video/cx18/cx18-av-vbi.c
index 23b31670bf1d..640121448eb9 100644
--- a/drivers/media/video/cx18/cx18-av-vbi.c
+++ b/drivers/media/video/cx18/cx18-av-vbi.c
@@ -255,8 +255,8 @@ int cx18_av_vbi_s_fmt(struct cx18 *cx, struct v4l2_format *fmt)
         }
 
         cx18_av_write(cx, 0x43c, 0x16);
-        /* FIXME - should match vblank set in cx18_av_std_setup() */
-        cx18_av_write(cx, 0x474, is_pal ? 0x2a : 26);
+        /* Should match vblank set in cx18_av_std_setup() */
+        cx18_av_write(cx, 0x474, is_pal ? 36 : 26);
         return 0;
 }
 
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index 41a1b2618aac..a0800393316e 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -371,9 +371,15 @@ static void cx18_vbi_setup(struct cx18_stream *s)
                  * Tell the encoder to capture 21-4+1=18 lines per field,
                  * since we want lines 10 through 21.
                  *
+                 * For 625/50 systems, according to the VIP 2 & BT.656 std:
+                 * The EAV RP code's Field bit toggles on line 1, a few lines
+                 * after the Vertcal Blank bit has already toggled.
+                 * Tell the encoder to capture 23-1+1=23 lines per field,
+                 * since we want lines 6 through 23.
+                 *
                  * FIXME - revisit for 625/50 systems
                  */
-                lines = cx->is_60hz ? (21 - 4 + 1) * 2 : 38;
+                lines = cx->is_60hz ? (21 - 4 + 1) * 2 : (23 - 1 + 1) * 2;
         }
 
         data[0] = s->handle;