[PATCH 3/4] drm/bridge: lt8912b: fix corrupted image output

Philippe Schenker dev at pschenker.ch
Thu Sep 22 12:43:05 UTC 2022


From: Francesco Dolcini <francesco.dolcini at toradex.com>

Correct I2C address for the register list in lt8912_write_lvds_config(),
these registers are on the first I2C address (0x48), the current
function is just writing garbage to the wrong registers and this creates
multiple issues (artifacts and output completely corrupted) on some HDMI
displays.

Correct I2C address comes from Lontium documentation and it is the one
used on other out-of-tree LT8912B drivers [1].

[1] https://github.com/boundarydevices/linux/blob/boundary-imx_5.10.x_2.0.0/drivers/video/lt8912.c#L296

Fixes: 30e2ae943c26 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Francesco Dolcini <francesco.dolcini at toradex.com>
Signed-off-by: Philippe Schenker <philippe.schenker at toradex.com>
---

 drivers/gpu/drm/bridge/lontium-lt8912b.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bridge/lontium-lt8912b.c
index 6a4bb7422176..5968f4af190b 100644
--- a/drivers/gpu/drm/bridge/lontium-lt8912b.c
+++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
@@ -188,7 +188,7 @@ static int lt8912_write_lvds_config(struct lt8912 *lt)
 		{0x03, 0xff},
 	};
 
-	return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
+	return regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq, ARRAY_SIZE(seq));
 };
 
 static inline struct lt8912 *bridge_to_lt8912(struct drm_bridge *b)
-- 
2.37.3



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