drm/msm/dp: move of_dp_aux_populate_bus() to eDP probe()

Currently eDP population is done at msm_dp_modeset_init() which happen
at binding time. Move eDP population to be done at display probe time
so that probe deferral cases can be handled effectively.
wait_for_hpd_asserted callback is added during drm_dp_aux_init()
to ensure eDP's HPD is up before proceeding eDP population.

Changes in v5:
-- inline dp_display_auxbus_population() and delete it

Changes in v4:
-- delete duplicate initialize code to dp_aux before drm_dp_aux_register()
-- delete of_get_child_by_name(dev->of_node, "aux-bus") and inline the
   function
-- not initialize rc = 0

Changes in v3:
-- add done_probing callback into devm_of_dp_aux_populate_bus()
Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/570074/
Link: https://lore.kernel.org/r/1701472789-25951-8-git-send-email-quic_khsieh@quicinc.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/dp/dp_aux.c

@@ -479,7 +479,6 @@ void dp_aux_deinit(struct drm_dp_aux *dp_aux)
 
 int dp_aux_register(struct drm_dp_aux *dp_aux)
 {
-	struct dp_aux_private *aux;
 	int ret;
 
 	if (!dp_aux) {
@@ -487,12 +486,7 @@ int dp_aux_register(struct drm_dp_aux *dp_aux)
 		return -EINVAL;
 	}
 
-	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
-
-	aux->dp_aux.name = "dpu_dp_aux";
-	aux->dp_aux.dev = aux->dev;
-	aux->dp_aux.transfer = dp_aux_transfer;
-	ret = drm_dp_aux_register(&aux->dp_aux);
+	ret = drm_dp_aux_register(dp_aux);
 	if (ret) {
 		DRM_ERROR("%s: failed to register drm aux: %d\n", __func__,
 				ret);
@@ -507,6 +501,21 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
 	drm_dp_aux_unregister(dp_aux);
 }
 
+static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
+				 unsigned long wait_us)
+{
+	int ret;
+	struct dp_aux_private *aux;
+
+	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
+
+	pm_runtime_get_sync(aux->dev);
+	ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
+	pm_runtime_put_sync(aux->dev);
+
+	return ret;
+}
+
 struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
 			      bool is_edp)
 {
@@ -530,6 +539,17 @@ struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
 	aux->catalog = catalog;
 	aux->retry_cnt = 0;
 
+	/*
+	 * Use the drm_dp_aux_init() to use the aux adapter
+	 * before registering AUX with the DRM device so that
+	 * msm eDP panel can be detected by generic_dep_panel_probe().
+	 */
+	aux->dp_aux.name = "dpu_dp_aux";
+	aux->dp_aux.dev = dev;
+	aux->dp_aux.transfer = dp_aux_transfer;
+	aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
+	drm_dp_aux_init(&aux->dp_aux);
+
 	return &aux->dp_aux;
 }
 

drivers/gpu/drm/msm/dp/dp_display.c

@@ -1198,6 +1198,17 @@ static const struct msm_dp_desc *dp_display_get_desc(struct platform_device *pde
 	return NULL;
 }
 
+static int dp_auxbus_done_probe(struct drm_dp_aux *aux)
+{
+	int rc;
+
+	rc = component_add(aux->dev, &dp_display_comp_ops);
+	if (rc)
+		DRM_ERROR("eDP component add failed, rc=%d\n", rc);
+
+	return rc;
+}
+
 static int dp_display_probe(struct platform_device *pdev)
 {
 	int rc = 0;
@@ -1263,10 +1274,18 @@ static int dp_display_probe(struct platform_device *pdev)
 	if (rc)
 		goto err;
 
-	rc = component_add(&pdev->dev, &dp_display_comp_ops);
-	if (rc) {
-		DRM_ERROR("component add failed, rc=%d\n", rc);
-		goto err;
+	if (dp->dp_display.is_edp) {
+		rc = devm_of_dp_aux_populate_bus(dp->aux, dp_auxbus_done_probe);
+		if (rc) {
+			DRM_ERROR("eDP auxbus population failed, rc=%d\n", rc);
+			goto err;
+		}
+	} else {
+		rc = component_add(&pdev->dev, &dp_display_comp_ops);
+		if (rc) {
+			DRM_ERROR("component add failed, rc=%d\n", rc);
+			goto err;
+		}
 	}
 
 	return rc;
@@ -1282,7 +1301,6 @@ static void dp_display_remove(struct platform_device *pdev)
 
 	component_del(&pdev->dev, &dp_display_comp_ops);
 	dp_display_deinit_sub_modules(dp);
-
 	platform_set_drvdata(pdev, NULL);
 }
 
@@ -1388,29 +1406,8 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
 {
 	int rc;
 	struct dp_display_private *dp_priv;
-	struct device_node *aux_bus;
-	struct device *dev;
 
 	dp_priv = container_of(dp, struct dp_display_private, dp_display);
-	dev = &dp_priv->dp_display.pdev->dev;
-	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
-
-	if (aux_bus && dp->is_edp) {
-		/*
-		 * The code below assumes that the panel will finish probing
-		 * by the time devm_of_dp_aux_populate_ep_devices() returns.
-		 * This isn't a great assumption since it will fail if the
-		 * panel driver is probed asynchronously but is the best we
-		 * can do without a bigger driver reorganization.
-		 */
-		rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
-		of_node_put(aux_bus);
-		if (rc)
-			goto error;
-	} else if (dp->is_edp) {
-		DRM_ERROR("eDP aux_bus not found\n");
-		return -ENODEV;
-	}
 
 	/*
 	 * External bridges are mandatory for eDP interfaces: one has to
@@ -1423,17 +1420,9 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
 	if (!dp->is_edp && rc == -ENODEV)
 		return 0;
 
-	if (!rc) {
+	if (!rc)
 		dp->next_bridge = dp_priv->parser->next_bridge;
-		return 0;
-	}
 
-error:
-	if (dp->is_edp) {
-		of_dp_aux_depopulate_bus(dp_priv->aux);
-		dp_display_host_phy_exit(dp_priv);
-		dp_display_host_deinit(dp_priv);
-	}
 	return rc;
 }