drm: bridge: Link encoder and bridge in core code

Instead of linking encoders and bridges in every driver (and getting it
wrong half of the time, as many drivers forget to set the drm_bridge
encoder pointer), do so in core code. The drm_bridge_attach() function
needs the encoder and optional previous bridge to perform that task,
update all the callers.

Signed-off-by: Laurent Pinchart <[e-mail]>
Acked-by: Stefan Agner <[e-mail]> # For DCU
Acked-by: Boris Brezillon <[e-mail]> # For atmel-hlcdc
Acked-by: Vincent Abriou <[e-mail]> # For STI
Acked-by: Maxime Ripard <[e-mail]> # For sun4i
Acked-by: Xinliang Liu <[e-mail]> # For hisilicon
Acked-by: Jyri Sarha <[e-mail]> # For tilcdc
Reviewed-by: Daniel Vetter <[e-mail]>
Signed-off-by: Archit Taneja <[e-mail]>
Link: http://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/arc/arcpgu_hdmi.c

···
 		return ret;
 
 	/* Link drm_bridge to encoder */
-	bridge->encoder = encoder;
-	encoder->bridge = bridge;
-
-	ret = drm_bridge_attach(drm, bridge);
+	ret = drm_bridge_attach(encoder, bridge, NULL);
 	if (ret)
 		drm_encoder_cleanup(encoder);
 

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c

···
 	of_node_put(np);
 
 	if (bridge) {
-		output->encoder.bridge = bridge;
-		bridge->encoder = &output->encoder;
-		ret = drm_bridge_attach(dev, bridge);
+		ret = drm_bridge_attach(&output->encoder, bridge, NULL);
 		if (!ret)
 			return 0;
 	}

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c

···
 
 	dp->bridge = bridge;
 
-	dp->encoder->bridge = bridge;
 	bridge->driver_private = dp;
-	bridge->encoder = dp->encoder;
 	bridge->funcs = &analogix_dp_bridge_funcs;
 
-	ret = drm_bridge_attach(drm_dev, bridge);
+	ret = drm_bridge_attach(dp->encoder, bridge, NULL);
 	if (ret) {
 		DRM_ERROR("failed to attach drm bridge\n");
 		return -EINVAL;

drivers/gpu/drm/bridge/dw-hdmi.c

···
 	hdmi->bridge = bridge;
 	bridge->driver_private = hdmi;
 	bridge->funcs = &dw_hdmi_bridge_funcs;
-	ret = drm_bridge_attach(drm, bridge);
+	ret = drm_bridge_attach(encoder, bridge, NULL);
 	if (ret) {
 		DRM_ERROR("Failed to initialize bridge with drm\n");
 		return -EINVAL;
 	}
 
-	encoder->bridge = bridge;
 	hdmi->connector.polled = DRM_CONNECTOR_POLL_HPD;
 
 	drm_connector_helper_add(&hdmi->connector,

drivers/gpu/drm/drm_bridge.c

···
 #include <linux/mutex.h>
 
 #include <drm/drm_bridge.h>
+#include <drm/drm_encoder.h>
 
 /**
  * DOC: overview
···
 EXPORT_SYMBOL(drm_bridge_remove);
 
 /**
- * drm_bridge_attach - associate given bridge to our DRM device
+ * drm_bridge_attach - attach the bridge to an encoder's chain
  *
- * @dev: DRM device
- * @bridge: bridge control structure
+ * @encoder: DRM encoder
+ * @bridge: bridge to attach
+ * @previous: previous bridge in the chain (optional)
  *
- * Called by a kms driver to link one of our encoder/bridge to the given
- * bridge.
+ * Called by a kms driver to link the bridge to an encoder's chain. The previous
+ * argument specifies the previous bridge in the chain. If NULL, the bridge is
+ * linked directly at the encoder's output. Otherwise it is linked at the
+ * previous bridge's output.
  *
- * Note that setting up links between the bridge and our encoder/bridge
- * objects needs to be handled by the kms driver itself.
+ * If non-NULL the previous bridge must be already attached by a call to this
+ * function.
  *
  * RETURNS:
  * Zero on success, error code on failure
  */
-int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge)
+int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
+		      struct drm_bridge *previous)
 {
-	if (!dev || !bridge)
+	int ret;
+
+	if (!encoder || !bridge)
+		return -EINVAL;
+
+	if (previous && (!previous->dev || previous->encoder != encoder))
 		return -EINVAL;
 
 	if (bridge->dev)
 		return -EBUSY;
 
-	bridge->dev = dev;
+	bridge->dev = encoder->dev;
+	bridge->encoder = encoder;
 
-	if (bridge->funcs->attach)
-		return bridge->funcs->attach(bridge);
+	if (bridge->funcs->attach) {
+		ret = bridge->funcs->attach(bridge);
+		if (ret < 0) {
+			bridge->dev = NULL;
+			bridge->encoder = NULL;
+			return ret;
+		}
+	}
+
+	if (previous)
+		previous->next = bridge;
+	else
+		encoder->bridge = bridge;
 
 	return 0;
 }

drivers/gpu/drm/drm_simple_kms_helper.c

···
 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
 					  struct drm_bridge *bridge)
 {
-	bridge->encoder = &pipe->encoder;
-	pipe->encoder.bridge = bridge;
-	return drm_bridge_attach(pipe->encoder.dev, bridge);
+	return drm_bridge_attach(&pipe->encoder, bridge, NULL);
 }
 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
 

drivers/gpu/drm/exynos/exynos_dp.c

···
 				   struct drm_connector *connector)
 {
 	struct exynos_dp_device *dp = to_dp(plat_data);
-	struct drm_encoder *encoder = &dp->encoder;
 	int ret;
 
 	drm_connector_register(connector);
···
 
 	/* Pre-empt DP connector creation if there's a bridge */
 	if (dp->ptn_bridge) {
-		bridge->next = dp->ptn_bridge;
-		dp->ptn_bridge->encoder = encoder;
-		ret = drm_bridge_attach(encoder->dev, dp->ptn_bridge);
+		ret = drm_bridge_attach(&dp->encoder, dp->ptn_bridge, bridge);
 		if (ret) {
 			DRM_ERROR("Failed to attach bridge to drm\n");
 			bridge->next = NULL;

drivers/gpu/drm/exynos/exynos_drm_dsi.c

···
 	}
 
 	bridge = of_drm_find_bridge(dsi->bridge_node);
-	if (bridge) {
-		encoder->bridge = bridge;
-		drm_bridge_attach(drm_dev, bridge);
-	}
+	if (bridge)
+		drm_bridge_attach(encoder, bridge, NULL);
 
 	return mipi_dsi_host_register(&dsi->dsi_host);
 }

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c

···
 	if (!bridge)
 		return -ENODEV;
 
-	fsl_dev->encoder.bridge = bridge;
-	bridge->encoder = &fsl_dev->encoder;
-
-	return drm_bridge_attach(fsl_dev->drm, bridge);
+	return drm_bridge_attach(&fsl_dev->encoder, bridge, NULL);
 }
 
 int fsl_dcu_create_outputs(struct fsl_dcu_drm_device *fsl_dev)

drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c

···
 	int ret;
 
 	/* associate the bridge to dsi encoder */
-	encoder->bridge = bridge;
-	bridge->encoder = encoder;
-
-	ret = drm_bridge_attach(dev, bridge);
+	ret = drm_bridge_attach(encoder, bridge, NULL);
 	if (ret) {
 		DRM_ERROR("failed to attach external bridge\n");
 		return ret;

drivers/gpu/drm/imx/imx-ldb.c

···
 			 DRM_MODE_ENCODER_LVDS, NULL);
 
 	if (imx_ldb_ch->bridge) {
-		imx_ldb_ch->bridge->encoder = encoder;
-
-		imx_ldb_ch->encoder.bridge = imx_ldb_ch->bridge;
-		ret = drm_bridge_attach(drm, imx_ldb_ch->bridge);
+		ret = drm_bridge_attach(&imx_ldb_ch->encoder,
+					imx_ldb_ch->bridge, NULL);
 		if (ret) {
 			DRM_ERROR("Failed to initialize bridge with drm\n");
 			return ret;

drivers/gpu/drm/imx/parallel-display.c

···
 		drm_panel_attach(imxpd->panel, &imxpd->connector);
 
 	if (imxpd->bridge) {
-		imxpd->bridge->encoder = encoder;
-		encoder->bridge = imxpd->bridge;
-		ret = drm_bridge_attach(drm, imxpd->bridge);
+		ret = drm_bridge_attach(encoder, imxpd->bridge, NULL);
 		if (ret < 0) {
 			dev_err(imxpd->dev, "failed to attach bridge: %d\n",
 				ret);

drivers/gpu/drm/mediatek/mtk_dpi.c

···
 struct mtk_dpi {
 	struct mtk_ddp_comp ddp_comp;
 	struct drm_encoder encoder;
+	struct drm_bridge *bridge;
 	void __iomem *regs;
 	struct device *dev;
 	struct clk *engine_clk;
···
 	/* Currently DPI0 is fixed to be driven by OVL1 */
 	dpi->encoder.possible_crtcs = BIT(1);
 
-	dpi->encoder.bridge->encoder = &dpi->encoder;
-	ret = drm_bridge_attach(dpi->encoder.dev, dpi->encoder.bridge);
+	ret = drm_bridge_attach(&dpi->encoder, dpi->bridge, NULL);
 	if (ret) {
 		dev_err(dev, "Failed to attach bridge: %d\n", ret);
 		goto err_cleanup;
···
 
 	dev_info(dev, "Found bridge node: %s\n", bridge_node->full_name);
 
-	dpi->encoder.bridge = of_drm_find_bridge(bridge_node);
+	dpi->bridge = of_drm_find_bridge(bridge_node);
 	of_node_put(bridge_node);
-	if (!dpi->encoder.bridge)
+	if (!dpi->bridge)
 		return -EPROBE_DEFER;
 
 	comp_id = mtk_ddp_comp_get_id(dev->of_node, MTK_DPI);

drivers/gpu/drm/mediatek/mtk_dsi.c

···
 	.get_modes = mtk_dsi_connector_get_modes,
 };
 
-static int mtk_drm_attach_bridge(struct drm_bridge *bridge,
-				 struct drm_encoder *encoder)
-{
-	int ret;
-
-	if (!bridge)
-		return -ENOENT;
-
-	encoder->bridge = bridge;
-	bridge->encoder = encoder;
-	ret = drm_bridge_attach(encoder->dev, bridge);
-	if (ret) {
-		DRM_ERROR("Failed to attach bridge to drm\n");
-		encoder->bridge = NULL;
-		bridge->encoder = NULL;
-	}
-
-	return ret;
-}
-
 static int mtk_dsi_create_connector(struct drm_device *drm, struct mtk_dsi *dsi)
 {
 	int ret;
···
 	dsi->encoder.possible_crtcs = 1;
 
 	/* If there's a bridge, attach to it and let it create the connector */
-	ret = mtk_drm_attach_bridge(dsi->bridge, &dsi->encoder);
+	ret = drm_bridge_attach(&dsi->encoder, dsi->bridge, NULL);
 	if (ret) {
+		DRM_ERROR("Failed to attach bridge to drm\n");
+
 		/* Otherwise create our own connector and attach to a panel */
 		ret = mtk_dsi_create_connector(drm, dsi);
 		if (ret)

drivers/gpu/drm/mediatek/mtk_hdmi.c

···
 
 struct mtk_hdmi {
 	struct drm_bridge bridge;
+	struct drm_bridge *next_bridge;
 	struct drm_connector conn;
 	struct device *dev;
 	struct phy *phy;
···
 		return ret;
 	}
 
-	if (bridge->next) {
-		bridge->next->encoder = bridge->encoder;
-		ret = drm_bridge_attach(bridge->encoder->dev, bridge->next);
+	if (hdmi->next_bridge) {
+		ret = drm_bridge_attach(bridge->encoder, hdmi->next_bridge,
+					bridge);
 		if (ret) {
 			dev_err(hdmi->dev,
 				"Failed to attach external bridge: %d\n", ret);
···
 	of_node_put(ep);
 
 	if (!of_device_is_compatible(remote, "hdmi-connector")) {
-		hdmi->bridge.next = of_drm_find_bridge(remote);
-		if (!hdmi->bridge.next) {
+		hdmi->next_bridge = of_drm_find_bridge(remote);
+		if (!hdmi->next_bridge) {
 			dev_err(dev, "Waiting for external bridge\n");
 			of_node_put(remote);
 			return -EPROBE_DEFER;

drivers/gpu/drm/msm/dsi/dsi_manager.c

···
 	struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
 	struct drm_bridge *bridge = NULL;
 	struct dsi_bridge *dsi_bridge;
+	struct drm_encoder *encoder;
 	int ret;
 
 	dsi_bridge = devm_kzalloc(msm_dsi->dev->dev,
···
 
 	dsi_bridge->id = id;
 
+	/*
+	 * HACK: we may not know the external DSI bridge device's mode
+	 * flags here. We'll get to know them only when the device
+	 * attaches to the dsi host. For now, assume the bridge supports
+	 * DSI video mode
+	 */
+	encoder = msm_dsi->encoders[MSM_DSI_VIDEO_ENCODER_ID];
+
 	bridge = &dsi_bridge->base;
 	bridge->funcs = &dsi_mgr_bridge_funcs;
 
-	ret = drm_bridge_attach(msm_dsi->dev, bridge);
+	ret = drm_bridge_attach(encoder, bridge, NULL);
 	if (ret)
 		goto fail;
 
···
 	encoder = msm_dsi->encoders[MSM_DSI_VIDEO_ENCODER_ID];
 
 	/* link the internal dsi bridge to the external bridge */
-	int_bridge->next = ext_bridge;
-	/* set the external bridge's encoder as dsi's encoder */
-	ext_bridge->encoder = encoder;
-
-	drm_bridge_attach(dev, ext_bridge);
+	drm_bridge_attach(encoder, ext_bridge, int_bridge);
 
 	/*
 	 * we need the drm_connector created by the external bridge

drivers/gpu/drm/msm/edp/edp_bridge.c

···
 	bridge = &edp_bridge->base;
 	bridge->funcs = &edp_bridge_funcs;
 
-	ret = drm_bridge_attach(edp->dev, bridge);
+	ret = drm_bridge_attach(edp->encoder, bridge, NULL);
 	if (ret)
 		goto fail;
 

drivers/gpu/drm/msm/hdmi/hdmi_bridge.c

···
 	bridge = &hdmi_bridge->base;
 	bridge->funcs = &msm_hdmi_bridge_funcs;
 
-	ret = drm_bridge_attach(hdmi->dev, bridge);
+	ret = drm_bridge_attach(hdmi->encoder, bridge, NULL);
 	if (ret)
 		goto fail;
 

drivers/gpu/drm/rcar-du/rcar_du_hdmienc.c

···
 	hdmienc->renc = renc;
 
 	/* Link the bridge to the encoder. */
-	bridge->encoder = encoder;
-	encoder->bridge = bridge;
-
-	ret = drm_bridge_attach(rcdu->ddev, bridge);
+	ret = drm_bridge_attach(encoder, bridge, NULL);
 	if (ret) {
 		drm_encoder_cleanup(encoder);
 		return ret;

drivers/gpu/drm/sti/sti_dvo.c

···
 		return err;
 	}
 
-	err = drm_bridge_attach(drm_dev, bridge);
+	err = drm_bridge_attach(encoder, bridge, NULL);
 	if (err) {
 		DRM_ERROR("Failed to attach bridge\n");
 		return err;
 	}
 
 	dvo->bridge = bridge;
-	encoder->bridge = bridge;
 	connector->encoder = encoder;
 	dvo->encoder = encoder;
 

drivers/gpu/drm/sti/sti_hda.c

···
 
 	bridge->driver_private = hda;
 	bridge->funcs = &sti_hda_bridge_funcs;
-	drm_bridge_attach(drm_dev, bridge);
+	drm_bridge_attach(encoder, bridge, NULL);
 
-	encoder->bridge = bridge;
 	connector->encoder = encoder;
 
 	drm_connector = (struct drm_connector *)connector;

drivers/gpu/drm/sti/sti_hdmi.c

···
 
 	bridge->driver_private = hdmi;
 	bridge->funcs = &sti_hdmi_bridge_funcs;
-	drm_bridge_attach(drm_dev, bridge);
+	drm_bridge_attach(encoder, bridge, NULL);
 
-	encoder->bridge = bridge;
 	connector->encoder = encoder;
 
 	drm_connector = (struct drm_connector *)connector;

drivers/gpu/drm/sun4i/sun4i_rgb.c

···
 	struct sun4i_drv *drv = drm->dev_private;
 	struct sun4i_tcon *tcon = drv->tcon;
 	struct drm_encoder *encoder;
+	struct drm_bridge *bridge;
 	struct sun4i_rgb *rgb;
 	int ret;
 
···
 	encoder = &rgb->encoder;
 
 	tcon->panel = sun4i_tcon_find_panel(tcon->dev->of_node);
-	encoder->bridge = sun4i_tcon_find_bridge(tcon->dev->of_node);
-	if (IS_ERR(tcon->panel) && IS_ERR(encoder->bridge)) {
+	bridge = sun4i_tcon_find_bridge(tcon->dev->of_node);
+	if (IS_ERR(tcon->panel) && IS_ERR(bridge)) {
 		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
 		return 0;
 	}
···
 		}
 	}
 
-	if (!IS_ERR(encoder->bridge)) {
-		encoder->bridge->encoder = &rgb->encoder;
-
-		ret = drm_bridge_attach(drm, encoder->bridge);
+	if (!IS_ERR(bridge)) {
+		ret = drm_bridge_attach(encoder, bridge, NULL);
 		if (ret) {
 			dev_err(drm->dev, "Couldn't attach our bridge\n");
 			goto err_cleanup_connector;
 		}
-	} else {
-		encoder->bridge = NULL;
 	}
 
 	return 0;

drivers/gpu/drm/tilcdc/tilcdc_external.c

···
 	int ret;
 
 	priv->external_encoder->possible_crtcs = BIT(0);
-	priv->external_encoder->bridge = bridge;
-	bridge->encoder = priv->external_encoder;
 
-	ret = drm_bridge_attach(ddev, bridge);
+	ret = drm_bridge_attach(priv->external_encoder, bridge, NULL);
 	if (ret) {
 		dev_err(ddev->dev, "drm_bridge_attach() failed %d\n", ret);
 		return ret;

include/drm/drm_bridge.h

···
 int drm_bridge_add(struct drm_bridge *bridge);
 void drm_bridge_remove(struct drm_bridge *bridge);
 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
-int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge);
+int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
+		      struct drm_bridge *previous);
 void drm_bridge_detach(struct drm_bridge *bridge);
 
 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,