diff --git a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
index ba43437014ce..b2794f815b3c 100644
--- a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
@@ -463,7 +463,6 @@ static struct exynos_drm_crtc_ops decon_crtc_ops = {
 	.win_commit		= decon_win_commit,
 	.win_disable		= decon_win_disable,
 	.te_handler		= decon_te_irq_handler,
-	.clear_channels		= decon_clear_channels,
 };
 
 static int decon_bind(struct device *dev, struct device *master, void *data)
@@ -497,7 +496,9 @@ static int decon_bind(struct device *dev, struct device *master, void *data)
 		goto err;
 	}
 
-	ret = drm_iommu_attach_device_if_possible(ctx->crtc, drm_dev, dev);
+	decon_clear_channels(ctx->crtc);
+
+	ret = drm_iommu_attach_device(drm_dev, dev);
 	if (ret)
 		goto err;
 
diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c
index 2c296353c9c3..a80b9184c866 100644
--- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c
@@ -126,7 +126,9 @@ static int decon_ctx_initialize(struct decon_context *ctx,
 	ctx->drm_dev = drm_dev;
 	ctx->pipe = priv->pipe++;
 
-	ret = drm_iommu_attach_device_if_possible(ctx->crtc, drm_dev, ctx->dev);
+	decon_clear_channels(ctx->crtc);
+
+	ret = drm_iommu_attach_device(drm_dev, ctx->dev);
 	if (ret)
 		priv->pipe--;
 
@@ -622,7 +624,6 @@ static const struct exynos_drm_crtc_ops decon_crtc_ops = {
 	.wait_for_vblank = decon_wait_for_vblank,
 	.win_commit = decon_win_commit,
 	.win_disable = decon_win_disable,
-	.clear_channels = decon_clear_channels,
 };
 
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.h b/drivers/gpu/drm/exynos/exynos_drm_drv.h
index dd00f160c1e5..7da593fd081f 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.h
@@ -177,7 +177,6 @@ struct exynos_drm_crtc_ops {
 	void (*win_disable)(struct exynos_drm_crtc *crtc, unsigned int zpos);
 	void (*te_handler)(struct exynos_drm_crtc *crtc);
 	void (*clock_enable)(struct exynos_drm_crtc *crtc, bool enable);
-	void (*clear_channels)(struct exynos_drm_crtc *crtc);
 };
 
 /*
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 300730c7af63..8d362b9365d3 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -887,7 +887,6 @@ static const struct exynos_drm_crtc_ops fimd_crtc_ops = {
 	.win_disable = fimd_win_disable,
 	.te_handler = fimd_te_handler,
 	.clock_enable = fimd_dp_clock_enable,
-	.clear_channels = fimd_clear_channels,
 };
 
 static irqreturn_t fimd_irq_handler(int irq, void *dev_id)
@@ -957,7 +956,9 @@ static int fimd_bind(struct device *dev, struct device *master, void *data)
 	if (ctx->display)
 		exynos_drm_create_enc_conn(drm_dev, ctx->display);
 
-	ret = drm_iommu_attach_device_if_possible(ctx->crtc, drm_dev, dev);
+	fimd_clear_channels(ctx->crtc);
+
+	ret = drm_iommu_attach_device(drm_dev, dev);
 	if (ret)
 		priv->pipe--;
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.c b/drivers/gpu/drm/exynos/exynos_drm_iommu.c
index 4c2ec1bef252..055e8ec2ef21 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_iommu.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.c
@@ -142,14 +142,3 @@ void drm_iommu_detach_device(struct drm_device *drm_dev,
 	iommu_detach_device(mapping->domain, subdrv_dev);
 	drm_release_iommu_mapping(drm_dev);
 }
-
-int drm_iommu_attach_device_if_possible(struct exynos_drm_crtc *exynos_crtc,
-			struct drm_device *drm_dev, struct device *subdrv_dev)
-{
-	if (is_drm_iommu_supported(drm_dev)) {
-		if (exynos_crtc->ops->clear_channels)
-			exynos_crtc->ops->clear_channels(exynos_crtc);
-	}
-
-	return drm_iommu_attach_device(drm_dev, subdrv_dev);
-}
diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.h b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
index a90357fc163d..dc1b5441f491 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_iommu.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
@@ -34,10 +34,6 @@ static inline bool is_drm_iommu_supported(struct drm_device *drm_dev)
 	return dev->archdata.mapping ? true : false;
 }
 
-int drm_iommu_attach_device_if_possible(
-		struct exynos_drm_crtc *exynos_crtc, struct drm_device *drm_dev,
-		struct device *subdrv_dev);
-
 #else
 
 static inline int drm_create_iommu_mapping(struct drm_device *drm_dev)
@@ -65,12 +61,5 @@ static inline bool is_drm_iommu_supported(struct drm_device *drm_dev)
 	return false;
 }
 
-static inline int drm_iommu_attach_device_if_possible(
-		struct exynos_drm_crtc *exynos_crtc, struct drm_device *drm_dev,
-		struct device *subdrv_dev)
-{
-	return 0;
-}
-
 #endif
 #endif
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index c6384feaf2a2..370e0a306ad0 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -884,8 +884,7 @@ static int mixer_initialize(struct mixer_context *mixer_ctx,
 		}
 	}
 
-	ret = drm_iommu_attach_device_if_possible(mixer_ctx->crtc, drm_dev,
-								mixer_ctx->dev);
+	ret = drm_iommu_attach_device(drm_dev, mixer_ctx->dev);
 	if (ret)
 		priv->pipe--;