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[2/2] v4l2-dv-timings: fix rounding in hblank and hsync calculation

Message ID 1428498569-6751-3-git-send-email-prladdha@cisco.com (mailing list archive)
State New, archived
Headers show

Commit Message

Prashant Laddha April 8, 2015, 1:09 p.m. UTC 
Changed the rounding calculation for hblank and hsync to match it
to equations in standards. Currently hblank and hsync are rounded
down. hblank needs to be rounded to nearest multiple of twice the
cell granularity. hsync needs to be rounded to nearest multiple of
cell granularity.

Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Martin Bugge <marbugge@cisco.com>
Signed-off-by: Prashant Laddha <prladdha@cisco.com>
---
 drivers/media/v4l2-core/v4l2-dv-timings.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c b/drivers/media/v4l2-core/v4l2-dv-timings.c
index 5e114ee..4b8ec4e 100644
--- a/drivers/media/v4l2-core/v4l2-dv-timings.c
+++ b/drivers/media/v4l2-core/v4l2-dv-timings.c
@@ -570,14 +570,15 @@  bool v4l2_detect_gtf(unsigned frame_height,
 			(hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) / 2) /
 			(hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000);
 
-	h_blank = h_blank - h_blank % (2 * GTF_CELL_GRAN);
+	h_blank = ((h_blank + GTF_CELL_GRAN) / (2 * GTF_CELL_GRAN)) *
+		  (2 * GTF_CELL_GRAN);
 	frame_width = image_width + h_blank;
 
 	pix_clk = (image_width + h_blank) * hfreq;
 	pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN;
 
 	hsync = (frame_width * 8 + 50) / 100;
-	hsync = hsync - hsync % GTF_CELL_GRAN;
+	hsync = ((hsync + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN) * GTF_CELL_GRAN;
 
 	h_fp = h_blank / 2 - hsync;