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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>
This commit is contained in:
Xin Ji 2021-09-03 11:11:44 +08:00 committed by Hung-Te Lin
parent 3d469fad97
commit 48ae111ca8
2 changed files with 16 additions and 1 deletions
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16
src/drivers/analogix/anx7625/anx7625.c
View File

@ -381,7 +381,7 @@ static int anx7625_dsi_video_config(uint8_t bus, struct display_timing *dt)
ret |= anx7625_reg_write(bus, RX_P1_ADDR, MIPI_PLL_N_NUM_7_0,
(n & 0xff));
/* diff */
ret |= anx7625_reg_write(bus, RX_P1_ADDR, MIPI_DIGITAL_ADJ_1, 0x3d);
ret |= anx7625_reg_write(bus, RX_P1_ADDR, MIPI_DIGITAL_ADJ_1, dt->k_val);
ret |= anx7625_odfc_config(bus, post_divider - 1);
@ -804,6 +804,20 @@ static void anx7625_parse_edid(const struct edid *edid,
dt->vback_porch = (edid->mode.vbl - edid->mode.vso -
edid->mode.vspw - edid->mode.vborder);
/*
* The k_val is a ratio to match MIPI input and DP output video clocks.
* Most panels can follow the default value (0x3d).
* IVO panels have smaller variation than DP CTS spec and need smaller
* k_val (0x3b).
*/
if (!strncmp(edid->manufacturer_name, "IVO", 3)) {
dt->k_val = 0x3b;
ANXINFO("detected IVO panel, use k value 0x3b\n");
} else {
dt->k_val = 0x3d;
ANXINFO("set default k value to 0x3d for panel\n");
}
ANXINFO("pixelclock(%d).\n"
" hactive(%d), hsync(%d), hfp(%d), hbp(%d)\n"
" vactive(%d), vsync(%d), vfp(%d), vbp(%d)\n",

1
src/drivers/analogix/anx7625/anx7625.h
View File

@ -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);