diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 6d524338d4ff..8abf89326424 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1315,6 +1315,31 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
 	pm_runtime_put_sync(dsi->dev);
 }
 
+static int samsung_dsim_atomic_check(struct drm_bridge *bridge,
+				     struct drm_bridge_state *bridge_state,
+				     struct drm_crtc_state *crtc_state,
+				     struct drm_connector_state *conn_state)
+{
+	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
+	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
+
+	if (dsi->plat_data->hw_type & SAMSUNG_DSIM_TYPE_IMX8MM) {
+		/**
+		 * FIXME:
+		 * At least LCDIF + DSIM needs active low sync,
+		 * but i.MX 8M Mini Applications Processor Reference Manual,
+		 * Rev. 3, 11/2020 says
+		 *
+		 * 13.6.3.5.2 RGB interface
+		 * Vsync, Hsync, and VDEN are active high signals.
+		 */
+		adjusted_mode->flags |= (DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
+		adjusted_mode->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
+	}
+
+	return 0;
+}
+
 static void samsung_dsim_mode_set(struct drm_bridge *bridge,
 				  const struct drm_display_mode *mode,
 				  const struct drm_display_mode *adjusted_mode)
@@ -1337,6 +1362,7 @@ static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
 	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
 	.atomic_reset			= drm_atomic_helper_bridge_reset,
+	.atomic_check			= samsung_dsim_atomic_check,
 	.atomic_pre_enable		= samsung_dsim_atomic_pre_enable,
 	.atomic_enable			= samsung_dsim_atomic_enable,
 	.atomic_disable			= samsung_dsim_atomic_disable,
diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
index 57b27d75369e..0c5a905f3de7 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -27,6 +27,7 @@ enum samsung_dsim_type {
 	SAMSUNG_DSIM_TYPE_EXYNOS5410,
 	SAMSUNG_DSIM_TYPE_EXYNOS5422,
 	SAMSUNG_DSIM_TYPE_EXYNOS5433,
+	SAMSUNG_DSIM_TYPE_IMX8MM,
 	SAMSUNG_DSIM_TYPE_COUNT,
 };