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

[CK Hu]

Hi, Jason:

On Mon, 2022-09-12 at 09:30 +0800, Jason-JH.Lin wrote:
> 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")

Fixes: 69a4237ab1d1 ("drm/mediatek: Separate gamma module")

and move this patch to the first patch of this series so this patch
could be picked to early stable branch.

Regards,
CK

> 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 d706f76fd30e..15fe2a4f98de 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;