From: Robert Foss <robert.foss@linaro.org>
Date: Tue, 13 Dec 2022 16:03:04 +0100
Subject: [PATCH] drm/bridge: lt9611: Fix PLL being unable to lock
References: bsc#1012628
Patch-mainline: 6.2.11
Git-commit: 2a9df204be0bbb896e087f00b9ee3fc559d5a608

commit 2a9df204be0bbb896e087f00b9ee3fc559d5a608 upstream.

This fixes PLL being unable to lock, and is derived from an equivalent
downstream commit.

Available LT9611 documentation does not list this register, neither does
LT9611UXC (which is a different chip).

This commit has been confirmed to fix HDMI output on DragonBoard 845c.

Suggested-by: Amit Pundir <amit.pundir@linaro.org>
Reviewed-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221213150304.4189760-1-robert.foss@linaro.org
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/gpu/drm/bridge/lontium-lt9611.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c b/drivers/gpu/drm/bridge/lontium-lt9611.c
index 3b77238c..ae8c6d9d 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
@@ -258,6 +258,7 @@ static int lt9611_pll_setup(struct lt9611 *lt9611, const struct drm_display_mode
 		{ 0x8126, 0x55 },
 		{ 0x8127, 0x66 },
 		{ 0x8128, 0x88 },
+		{ 0x812a, 0x20 },
 	};
 
 	regmap_multi_reg_write(lt9611->regmap, reg_cfg, ARRAY_SIZE(reg_cfg));
-- 
2.35.3