[PATCH 5.15 50/83] drm/bridge: lt8912b: add vsync hsync

[Greg Kroah-Hartman]

From: Philippe Schenker <philippe.schenker@xxxxxxxxxxx>

[ Upstream commit da73a94fa282f78d485bd0aab36c8ac15b6f792c ]

Currently the bridge driver does not take care whether or not the display
needs positive/negative vertical/horizontal syncs. Pass these two flags
to the bridge from the EDID that was read out from the display.

Fixes: 30e2ae943c26 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Philippe Schenker <philippe.schenker@xxxxxxxxxxx>
Acked-by: Adrien Grassein <adrien.grassein@xxxxxxxxx>
Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-2-dev@xxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/bridge/lontium-lt8912b.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bridge/lontium-lt8912b.c
index 1b0c7eaf6c84..0fae72d45040 100644
--- a/drivers/gpu/drm/bridge/lontium-lt8912b.c
+++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
@@ -266,7 +266,7 @@ static int lt8912_video_setup(struct lt8912 *lt)
 	u32 hactive, h_total, hpw, hfp, hbp;
 	u32 vactive, v_total, vpw, vfp, vbp;
 	u8 settle = 0x08;
-	int ret;
+	int ret, hsync_activehigh, vsync_activehigh;
 
 	if (!lt)
 		return -EINVAL;
@@ -276,12 +276,14 @@ static int lt8912_video_setup(struct lt8912 *lt)
 	hpw = lt->mode.hsync_len;
 	hbp = lt->mode.hback_porch;
 	h_total = hactive + hfp + hpw + hbp;
+	hsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_HSYNC_HIGH;
 
 	vactive = lt->mode.vactive;
 	vfp = lt->mode.vfront_porch;
 	vpw = lt->mode.vsync_len;
 	vbp = lt->mode.vback_porch;
 	v_total = vactive + vfp + vpw + vbp;
+	vsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_VSYNC_HIGH;
 
 	if (vactive <= 600)
 		settle = 0x04;
@@ -315,6 +317,11 @@ static int lt8912_video_setup(struct lt8912 *lt)
 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3e, hfp & 0xff);
 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3f, hfp >> 8);
 
+	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(0),
+				  vsync_activehigh ? BIT(0) : 0);
+	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(1),
+				  hsync_activehigh ? BIT(1) : 0);
+
 	return ret;
 }
 
-- 
2.35.1