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From:   Robert Foss <robert.foss@linaro.org>
To:     andrzej.hajda@intel.com, neil.armstrong@linaro.org,
        robert.foss@linaro.org, Laurent.pinchart@ideasonboard.com,
        jonas@kwiboo.se, jernej.skrabec@gmail.com, airlied@gmail.com,
        daniel@ffwll.ch, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, Amit Pundir <amit.pundir@linaro.org>
Subject: [PATCH v1] drm/bridge: lt9611: Fix PLL being unable to lock
Date:   Tue, 13 Dec 2022 16:03:04 +0100
Message-Id: <20221213150304.4189760-1-robert.foss@linaro.org>
MIME-Version: 1.0
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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>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
---
 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 ffcdc8dba3798..3ce4e495aee50 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
@@ -259,6 +259,7 @@ 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));
-- 
2.34.1