[PATCH v3 8/9] drm/mediatek: Add clear RELAY_MODE bit to set gamma

[Jason-JH.Lin]

Since the bootlaoder may set the RELAY_MODE to gamma be for the kerenl,
we have to clear the RELAY_MODE bit to make sure that the gamma is
enabled correctly.

Fixes: b10023b03082 ("FROMGIT: drm/mediatek: Separate gamma module")
Signed-off-by: Jason-JH.Lin <jason-jh.lin at mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
index 4e67f1503b9a..77cc344b9c02 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
@@ -18,6 +18,7 @@
 #define DISP_GAMMA_EN				0x0000
 #define GAMMA_EN					BIT(0)
 #define DISP_GAMMA_CFG				0x0020
+#define RELAY_MODE					BIT(0)
 #define GAMMA_LUT_EN					BIT(1)
 #define GAMMA_DITHERING					BIT(2)
 #define DISP_GAMMA_SIZE				0x0030
@@ -99,6 +100,7 @@ void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crt
 
 	if (state->gamma_lut) {
 		reg = readl(regs + DISP_GAMMA_CFG);
+		reg = reg & ~RELAY_MODE;
 		reg = reg | GAMMA_LUT_EN;
 		writel(reg, regs + DISP_GAMMA_CFG);
 		lut_base = regs + DISP_GAMMA_LUT;
-- 
2.18.0