[PATCH for-5.10+] drm/bridge: lt9611: Fix PLL being unable to lock

[PATCH for-5.10+] drm/bridge: lt9611: Fix PLL being unable to lock

[Amit Pundir]

From: Robert Foss <robert.foss@linaro.org>

[ Upstream commit 2a9df204be0bbb896e087f00b9ee3fc559d5a608 ]

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>
---

To be cherry-picked on v5.10.y, v5.15.y and v6.1.y.

 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 3b77238ca4af..ae8c6d9d4095 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));
-- 
2.25.1

Re: [PATCH for-5.10+] drm/bridge: lt9611: Fix PLL being unable to lock

[Greg KH]

On Wed, Apr 05, 2023 at 02:50:52PM +0530, Amit Pundir wrote:
> From: Robert Foss <robert.foss@linaro.org>
> 
> [ Upstream commit 2a9df204be0bbb896e087f00b9ee3fc559d5a608 ]
> 
> 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>
> ---
> 
> To be cherry-picked on v5.10.y, v5.15.y and v6.1.y.

You forgot 6.2.y, added there too...