drm/msm/dp: Add eDP support via aux_bus

This patch adds support for generic eDP sink through aux_bus. The eDP/DP
controller driver should support aux transactions originating from the
panel-edp driver and hence should be initialized and ready.

The panel bridge supporting the panel should be ready before the bridge
connector is initialized. The generic panel probe needs the controller
resources to be enabled to support the aux transactions originating from
the panel probe.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/483307/
Link: https://lore.kernel.org/r/1650887072-16652-2-git-send-email-quic_sbillaka@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

1 files changed, 68 insertions, 3 deletions

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index b37bc1c74d88..b99f918d90f3 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -10,6 +10,7 @@
 #include <linux/component.h>
 #include <linux/of_irq.h>
 #include <linux/delay.h>
+#include <drm/dp/drm_dp_aux_bus.h>
 
 #include "msm_drv.h"
 #include "msm_kms.h"
@@ -263,13 +264,12 @@ static int dp_display_bind(struct device *dev, struct device *master,
 	dp->dp_display.drm_dev = drm;
 	priv->dp[dp->id] = &dp->dp_display;
 
-	rc = dp->parser->parse(dp->parser, dp->dp_display.connector_type);
+	rc = dp->parser->parse(dp->parser);
 	if (rc) {
 		DRM_ERROR("device tree parsing failed\n");
 		goto end;
 	}
 
-	dp->dp_display.next_bridge = dp->parser->next_bridge;
 
 	dp->drm_dev = drm;
 	dp->aux->drm_dev = drm;
@@ -1288,6 +1288,8 @@ static int dp_display_probe(struct platform_device *pdev)
 	dp->name = "drm_dp";
 	dp->dp_display.connector_type = desc->connector_type;
 	dp->wide_bus_en = desc->wide_bus_en;
+	dp->dp_display.is_edp =
+		(dp->dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);
 
 	rc = dp_init_sub_modules(dp);
 	if (rc) {
@@ -1481,7 +1483,8 @@ void msm_dp_irq_postinstall(struct msm_dp *dp_display)
 
 	dp = container_of(dp_display, struct dp_display_private, dp_display);
 
-	dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
+	if (!dp_display->is_edp)
+		dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
 }
 
 bool msm_dp_wide_bus_available(const struct msm_dp *dp_display)
@@ -1512,6 +1515,64 @@ void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
 	}
 }
 
+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->pdev->dev;
+	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
+
+	if (aux_bus && dp->is_edp) {
+		dp_display_host_init(dp_priv);
+		dp_catalog_ctrl_hpd_config(dp_priv->catalog);
+		dp_display_host_phy_init(dp_priv);
+		enable_irq(dp_priv->irq);
+
+		/*
+		 * 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 = devm_of_dp_aux_populate_ep_devices(dp_priv->aux);
+		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
+	 * provide at least an eDP panel (which gets wrapped into panel-bridge).
+	 *
+	 * For DisplayPort interfaces external bridges are optional, so
+	 * silently ignore an error if one is not present (-ENODEV).
+	 */
+	rc = dp_parser_find_next_bridge(dp_priv->parser);
+	if (!dp->is_edp && rc == -ENODEV)
+		return 0;
+
+	if (!rc) {
+		dp->next_bridge = dp_priv->parser->next_bridge;
+		return 0;
+	}
+
+error:
+	if (dp->is_edp) {
+		disable_irq(dp_priv->irq);
+		dp_display_host_phy_exit(dp_priv);
+		dp_display_host_deinit(dp_priv);
+	}
+	return rc;
+}
+
 int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
 			struct drm_encoder *encoder)
 {
@@ -1535,6 +1596,10 @@ int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
 
 	dp_display->encoder = encoder;
 
+	ret = dp_display_get_next_bridge(dp_display);
+	if (ret)
+		return ret;
+
 	dp_display->bridge = dp_bridge_init(dp_display, dev, encoder);
 	if (IS_ERR(dp_display->bridge)) {
 		ret = PTR_ERR(dp_display->bridge);