From 2c5d69b0a141e1e98febe3111e6f4fd8420493a5 Mon Sep 17 00:00:00 2001
From: Miles Chen <miles.chen@mediatek.com>
Date: Wed, 16 Mar 2022 07:23:00 +0800
Subject: [PATCH] drm/mediatek: Fix mtk_cec_mask()
Git-commit: 2c5d69b0a141e1e98febe3111e6f4fd8420493a5
Patch-mainline: v5.19-rc1
References: git-fixes

In current implementation, mtk_cec_mask() writes val into target register
and ignores the mask. After talking to our hdmi experts, mtk_cec_mask()
should read a register, clean only mask bits, and update (val | mask) bits
to the register.

Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220315232301.2434-1-miles.chen@mediatek.com/
Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>
Cc: CK Hu <ck.hu@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/mediatek/mtk_cec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_cec.c b/drivers/gpu/drm/mediatek/mtk_cec.c
index e9cef5c0c8f7..cdfa648910b2 100644
--- a/drivers/gpu/drm/mediatek/mtk_cec.c
+++ b/drivers/gpu/drm/mediatek/mtk_cec.c
@@ -85,7 +85,7 @@ static void mtk_cec_mask(struct mtk_cec *cec, unsigned int offset,
 	u32 tmp = readl(cec->regs + offset) & ~mask;
 
 	tmp |= val & mask;
-	writel(val, cec->regs + offset);
+	writel(tmp, cec->regs + offset);
 }
 
 void mtk_cec_set_hpd_event(struct device *dev,
-- 
2.35.3