diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c b/drivers/gpu/drm/rcar-du/rcar_du_group.c
index a3e29bb420fd..2f37ea901873 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
@@ -212,6 +212,9 @@ void rcar_du_group_restart(struct rcar_du_group *rgrp)
 
 int rcar_du_set_dpad0_vsp1_routing(struct rcar_du_device *rcdu)
 {
+	struct rcar_du_group *rgrp;
+	struct rcar_du_crtc *crtc;
+	unsigned int index;
 	int ret;
 
 	if (!rcar_du_has(rcdu, RCAR_DU_FEATURE_EXT_CTRL_REGS))
@@ -219,17 +222,22 @@ int rcar_du_set_dpad0_vsp1_routing(struct rcar_du_device *rcdu)
 
 	/*
 	 * RGB output routing to DPAD0 and VSP1D routing to DU0/1/2 are
-	 * configured in the DEFR8 register of the first group. As this function
-	 * can be called with the DU0 and DU1 CRTCs disabled, we need to enable
-	 * the first group clock before accessing the register.
+	 * configured in the DEFR8 register of the first group on Gen2 and the
+	 * last group on Gen3. As this function can be called with the DU
+	 * channels of the corresponding CRTCs disabled, we need to enable the
+	 * group clock before accessing the register.
 	 */
-	ret = clk_prepare_enable(rcdu->crtcs[0].clock);
+	index = rcdu->info->gen < 3 ? 0 : DIV_ROUND_UP(rcdu->num_crtcs, 2) - 1;
+	rgrp = &rcdu->groups[index];
+	crtc = &rcdu->crtcs[index * 2];
+
+	ret = clk_prepare_enable(crtc->clock);
 	if (ret < 0)
 		return ret;
 
-	rcar_du_group_setup_defr8(&rcdu->groups[0]);
+	rcar_du_group_setup_defr8(rgrp);
 
-	clk_disable_unprepare(rcdu->crtcs[0].clock);
+	clk_disable_unprepare(crtc->clock);
 
 	return 0;
 }