drivers/analogix/anx7625: prevent video clock jitter on IVO panels

The MIPI source video data has a large variation (e.g. 59Hz ~ 61Hz),
anx7625 defines K ratio for matching MIPI input video clock and
DP output video clock. A bigger k value can match a bigger video data
variation. IVO panel has smaller variation than DP CTS spec, so decrease
k value to 0x3b.

BUG=b:194659777
BRANCH=none
TEST=Display is normal on Asurada

Change-Id: If3a09811999babda45e9a9a559dd447920109204
Signed-off-by: Xin Ji <xji@analogixsemi.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57439
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/drivers/analogix/anx7625/anx7625.h b/src/drivers/analogix/anx7625/anx7625.h
index c0b33b2eea..bba42cb61a 100644
--- a/src/drivers/analogix/anx7625/anx7625.h
+++ b/src/drivers/analogix/anx7625/anx7625.h
@@ -350,6 +350,7 @@ struct display_timing {
 	unsigned int vfront_porch;
 	unsigned int vback_porch;
 	unsigned int vsync_len;
+	unsigned int k_val;
 };
 
 int anx7625_dp_start(uint8_t bus, const struct edid *edid);