[PATCH] drm/mediatek: dpi: fix NULL dereference in mtk_dpi_bridge_atomic_check

[CK Hu]

Hi, Frank:

On Mon, 2021-07-12 at 10:07 +0200, Frank Wunderlich wrote:
> From: Frank Wunderlich <frank-w at public-files.de>
> 
> bridge->driver_private is not set (NULL) so use bridge_to_dpi(bridge)
> like it's done in bridge_atomic_get_output_bus_fmts

Reviewed-by: CK Hu <ck.hu at mediatek.com>

> 
> Fixes: ec8747c52434 ("drm/mediatek: dpi: Add bus format negotiation")
> Signed-off-by: Frank Wunderlich <frank-w at public-files.de>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index bced555648b0..a2eca1f66984 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -605,7 +605,7 @@ static int mtk_dpi_bridge_atomic_check(struct drm_bridge *bridge,
>  				       struct drm_crtc_state *crtc_state,
>  				       struct drm_connector_state *conn_state)
>  {
> -	struct mtk_dpi *dpi = bridge->driver_private;
> +	struct mtk_dpi *dpi = bridge_to_dpi(bridge);
>  	unsigned int out_bus_format;
>  
>  	out_bus_format = bridge_state->output_bus_cfg.format;