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>

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index b37bc1c74d88c9b2300c52352b7c60b72bd08207..b99f918d90f31d95134e615b618b62c02d3cad47 100644 (file)
--- 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);

diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index f1adf2b84975a017c994deb95db642495b7c48c2..4f9fe4d7610b354cc40977032d773c00d6e63a22 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -21,6 +21,7 @@ struct msm_dp {
        bool audio_enabled;
        bool power_on;
        unsigned int connector_type;
+       bool is_edp;
 
        hdmi_codec_plugged_cb plugged_cb;
 

diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index 5f6658ebd7379ba12fc1b8773f3c82d15fdf469a..62d58b9c46472edb48eb388382aac0f8435d0f67 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -87,10 +87,23 @@ 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;
+       /*
+        * Many ops only make sense for DP. Why?
+        * - Detect/HPD are used by DRM to know if a display is _physically_
+        *   there, not whether the display is powered on / finished initting.
+        *   On eDP we assume the display is always there because you can't
+        *   know until power is applied. If we don't implement the ops DRM will
+        *   assume our display is always there.
+        * - Currently eDP mode reading is driven by the panel driver. This
+        *   allows the panel driver to properly power itself on to read the
+        *   modes.
+        */
+       if (!dp_display->is_edp) {
+               bridge->ops =
+                       DRM_BRIDGE_OP_DETECT |
+                       DRM_BRIDGE_OP_HPD |
+                       DRM_BRIDGE_OP_MODES;
+       }
 
        drm_bridge_add(bridge);
 

diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
index 8ad587f7b8d3a0ff1186e7c4045e7ef25c777ba6..8f9fed9fdafc49cd248cfdd26b731da558b9561d 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_parser.c
+++ b/drivers/gpu/drm/msm/dp/dp_parser.c
@@ -263,7 +263,7 @@ 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;
@@ -277,7 +277,7 @@ static int dp_parser_find_next_bridge(struct dp_parser *parser)
        return 0;
 }
 
-static int dp_parser_parse(struct dp_parser *parser, int connector_type)
+static int dp_parser_parse(struct dp_parser *parser)
 {
        int rc = 0;
 
@@ -298,25 +298,6 @@ 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 d371bae1c96822ad70486dfb66d642def33019e5..3a4d7972c0697607f20488788d75e2a8d5113377 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_parser.h
+++ b/drivers/gpu/drm/msm/dp/dp_parser.h
@@ -125,7 +125,7 @@ struct dp_parser {
        u32 max_dp_lanes;
        struct drm_bridge *next_bridge;
 
-       int (*parse)(struct dp_parser *parser, int connector_type);
+       int (*parse)(struct dp_parser *parser);
 };
 
 /**
@@ -141,4 +141,16 @@ struct dp_parser {
  */
 struct dp_parser *dp_parser_get(struct platform_device *pdev);
 
+/**
+ * dp_parser_find_next_bridge() - find an additional bridge to DP
+ *
+ * @parser: dp_parser data from client
+ *
+ * This function is used to find any additional bridge attached to
+ * the DP controller. The eDP interface requires a panel bridge.
+ *
+ * Return: 0 if able to get the bridge, otherwise negative errno for failure.
+ */
+int dp_parser_find_next_bridge(struct dp_parser *parser);
+
 #endif