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From:   Sankeerth Billakanti <quic_sbillaka@quicinc.com>
To:     <dri-devel@lists.freedesktop.org>, <linux-arm-msm@vger.kernel.org>,
        <freedreno@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>
CC:     Sankeerth Billakanti <quic_sbillaka@quicinc.com>,
        <robdclark@gmail.com>, <seanpaul@chromium.org>,
        <swboyd@chromium.org>, <quic_kalyant@quicinc.com>,
        <quic_abhinavk@quicinc.com>, <dianders@chromium.org>,
        <quic_khsieh@quicinc.com>, <agross@kernel.org>,
        <bjorn.andersson@linaro.org>, <robh+dt@kernel.org>,
        <krzk+dt@kernel.org>, <sean@poorly.run>, <airlied@linux.ie>,
        <daniel@ffwll.ch>, <thierry.reding@gmail.com>, <sam@ravnborg.org>,
        <dmitry.baryshkov@linaro.org>, <quic_vproddut@quicinc.com>
Subject: [PATCH v5 5/9] drm/msm/dp: Add eDP support via aux_bus
Date:   Wed, 16 Mar 2022 23:05:50 +0530
Message-ID: <1647452154-16361-6-git-send-email-quic_sbillaka@quicinc.com>
In-Reply-To: <1647452154-16361-1-git-send-email-quic_sbillaka@quicinc.com>
References: <1647452154-16361-1-git-send-email-quic_sbillaka@quicinc.com>
MIME-Version: 1.0
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Precedence: bulk

	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 aux tractions originating
from it. So, the host_init and phy_init are moved to execute before the
panel probe.

	The host_init has to return early if the core is already
initialized so that the regulator and clock votes for the controller
resources are balanced.

	EV_HPD_INIT_SETUP needs to execute immediately to enable the
interrupts for the aux transactions from panel-edp to get the modes
supported.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 65 +++++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/msm/dp/dp_drm.c     | 10 +++---
 drivers/gpu/drm/msm/dp/dp_parser.c  | 21 +-----------
 drivers/gpu/drm/msm/dp/dp_parser.h  |  1 +
 4 files changed, 70 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 382b3aa..688bbed 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/drm_dp_aux_bus.h>
 
 #include "msm_drv.h"
 #include "msm_kms.h"
@@ -265,8 +266,6 @@ static int dp_display_bind(struct device *dev, struct device *master,
 		goto end;
 	}
 
-	dp->dp_display.next_bridge = dp->parser->next_bridge;
-
 	dp->aux->drm_dev = drm;
 	rc = dp_aux_register(dp->aux);
 	if (rc) {
@@ -421,6 +420,11 @@ static void dp_display_host_init(struct dp_display_private *dp)
 		dp->dp_display.connector_type, dp->core_initialized,
 		dp->phy_initialized);
 
+	if (dp->core_initialized) {
+		DRM_DEBUG_DP("DP core already initialized\n");
+		return;
+	}
+
 	dp_power_init(dp->power, false);
 	dp_ctrl_reset_irq_ctrl(dp->ctrl, true);
 	dp_aux_init(dp->aux);
@@ -433,6 +437,11 @@ static void dp_display_host_deinit(struct dp_display_private *dp)
 		dp->dp_display.connector_type, dp->core_initialized,
 		dp->phy_initialized);
 
+	if (!dp->core_initialized) {
+		DRM_DEBUG_DP("DP core not initialized\n");
+		return;
+	}
+
 	dp_ctrl_reset_irq_ctrl(dp->ctrl, false);
 	dp_aux_deinit(dp->aux);
 	dp_power_deinit(dp->power);
@@ -1502,7 +1511,7 @@ void msm_dp_irq_postinstall(struct msm_dp *dp_display)
 
 	dp_hpd_event_setup(dp);
 
-	dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
+	dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 0);
 }
 
 void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
@@ -1524,6 +1533,52 @@ 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 = 0;
+	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_display_host_init(dp_priv);
+		dp_catalog_ctrl_hpd_config(dp_priv->catalog);
+		enable_irq(dp_priv->irq);
+		dp_display_host_phy_init(dp_priv);
+
+		devm_of_dp_aux_populate_ep_devices(dp_priv->aux);
+
+		disable_irq(dp_priv->irq);
+	}
+
+	/*
+	 * 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 (rc == -ENODEV) {
+		if (dp->connector_type == DRM_MODE_CONNECTOR_eDP) {
+			DRM_ERROR("eDP: next bridge is not present\n");
+			return rc;
+		}
+	} else if (rc) {
+		if (rc != -EPROBE_DEFER)
+			DRM_ERROR("DP: error parsing next bridge: %d\n", rc);
+		return rc;
+	}
+
+	dp->next_bridge = dp_priv->parser->next_bridge;
+
+	return 0;
+}
+
 int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
 			struct drm_encoder *encoder)
 {
@@ -1547,6 +1602,10 @@ 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);
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index 7ce1aca..5254bd6 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -114,10 +114,12 @@ struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *
 	bridge->funcs = &dp_bridge_ops;
 	bridge->type = dp_display->connector_type;
 
-	bridge->ops =
-		DRM_BRIDGE_OP_DETECT |
-		DRM_BRIDGE_OP_HPD |
-		DRM_BRIDGE_OP_MODES;
+	if (bridge->type == DRM_MODE_CONNECTOR_DisplayPort) {
+		bridge->ops =
+			DRM_BRIDGE_OP_DETECT |
+			DRM_BRIDGE_OP_HPD |
+			DRM_BRIDGE_OP_MODES;
+	}
 
 	rc = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (rc) {
diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
index 1056b8d..6317dce 100644
--- a/drivers/gpu/drm/msm/dp/dp_parser.c
+++ b/drivers/gpu/drm/msm/dp/dp_parser.c
@@ -265,7 +265,7 @@ static int dp_parser_clock(struct dp_parser *parser)
 	return 0;
 }
 
-static int dp_parser_find_next_bridge(struct dp_parser *parser)
+int dp_parser_find_next_bridge(struct dp_parser *parser)
 {
 	struct device *dev = &parser->pdev->dev;
 	struct drm_bridge *bridge;
@@ -300,25 +300,6 @@ static int dp_parser_parse(struct dp_parser *parser, int connector_type)
 	if (rc)
 		return rc;
 
-	/*
-	 * 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(parser);
-	if (rc == -ENODEV) {
-		if (connector_type == DRM_MODE_CONNECTOR_eDP) {
-			DRM_ERROR("eDP: next bridge is not present\n");
-			return rc;
-		}
-	} else if (rc) {
-		if (rc != -EPROBE_DEFER)
-			DRM_ERROR("DP: error parsing next bridge: %d\n", rc);
-		return rc;
-	}
-
 	/* Map the corresponding regulator information according to
 	 * version. Currently, since we only have one supported platform,
 	 * mapping the regulator directly.
diff --git a/drivers/gpu/drm/msm/dp/dp_parser.h b/drivers/gpu/drm/msm/dp/dp_parser.h
index d371bae..091ff41 100644
--- a/drivers/gpu/drm/msm/dp/dp_parser.h
+++ b/drivers/gpu/drm/msm/dp/dp_parser.h
@@ -140,5 +140,6 @@ struct dp_parser {
  * can be parsed using this module.
  */
 struct dp_parser *dp_parser_get(struct platform_device *pdev);
+int dp_parser_find_next_bridge(struct dp_parser *parser);
 
 #endif
-- 
2.7.4