[RFC PATCH 4/4] drm/msm/dp: Implement hpd_notify()

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

From: Bjorn Andersson <bjorn.andersson@linaro.org>

The Qualcomm DisplayPort driver contains traces of the necessary
plumbing to hook up USB HPD, in the form of the dp_hpd module and the
dp_usbpd_cb struct. Use this as basis for implementing the
hpd_notify() callback, by amending the dp_hpd module with the
missing logic.

Overall the solution is similar to what's done downstream, but upstream
all the code to disect the HPD notification lives on the calling side of
drm_connector_oob_hotplug_event().

drm_connector_oob_hotplug_event() performs the lookup of the
drm_connector based on fwnode, hence the need to assign the fwnode in
dp_drm_connector_init().

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[DB: rebased to use drm_bridge_connector]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 11 +++++++++++
 drivers/gpu/drm/msm/dp/dp_display.h |  1 +
 drivers/gpu/drm/msm/dp/dp_drm.c     |  3 +++
 drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
 drivers/gpu/drm/msm/dp/dp_hpd.c     | 21 +++++++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_hpd.h     |  5 +++++
 6 files changed, 43 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index c38832304353..31540d1409eb 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1300,6 +1300,7 @@ static int dp_display_probe(struct platform_device *pdev)
 	if (!desc)
 		return -EINVAL;
 
+	dp->dp_display.dev = &pdev->dev;
 	dp->pdev = pdev;
 	dp->name = "drm_dp";
 	dp->dp_display.connector_type = desc->connector_type;
@@ -1789,3 +1790,13 @@ void dp_bridge_mode_set(struct drm_bridge *drm_bridge,
 	dp_display->dp_mode.h_active_low =
 		!!(dp_display->dp_mode.drm_mode.flags & DRM_MODE_FLAG_NHSYNC);
 }
+
+void dp_bridge_hpd_notify(struct drm_bridge *bridge,
+			  enum drm_connector_status status)
+{
+	struct msm_dp_bridge *dp_bridge = to_dp_bridge(bridge);
+	struct msm_dp *dp = dp_bridge->dp_display;
+	struct dp_display_private *dp_display = container_of(dp, struct dp_display_private, dp_display);
+
+	dp_display->usbpd->hpd_notify(dp_display->usbpd, status);
+}
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index 4f9fe4d7610b..2d2614bc5a14 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -11,6 +11,7 @@
 #include "disp/msm_disp_snapshot.h"
 
 struct msm_dp {
+	struct device *dev;
 	struct drm_device *drm_dev;
 	struct device *codec_dev;
 	struct drm_bridge *bridge;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index 62d58b9c4647..821cfd37b1fb 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -68,6 +68,7 @@ static const struct drm_bridge_funcs dp_bridge_ops = {
 	.mode_valid   = dp_bridge_mode_valid,
 	.get_modes    = dp_bridge_get_modes,
 	.detect       = dp_bridge_detect,
+	.hpd_notify   = dp_bridge_hpd_notify,
 };
 
 struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
@@ -138,6 +139,8 @@ struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display)
 	if (IS_ERR(connector))
 		return connector;
 
+	connector->fwnode = fwnode_handle_get(dev_fwnode(dp_display->dev));
+
 	drm_connector_attach_encoder(connector, dp_display->encoder);
 
 	return connector;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
index f4b1ed1e24f7..3b7480a86844 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.h
+++ b/drivers/gpu/drm/msm/dp/dp_drm.h
@@ -32,5 +32,7 @@ enum drm_mode_status dp_bridge_mode_valid(struct drm_bridge *bridge,
 void dp_bridge_mode_set(struct drm_bridge *drm_bridge,
 			const struct drm_display_mode *mode,
 			const struct drm_display_mode *adjusted_mode);
+void dp_bridge_hpd_notify(struct drm_bridge *bridge,
+			  enum drm_connector_status status);
 
 #endif /* _DP_DRM_H_ */
diff --git a/drivers/gpu/drm/msm/dp/dp_hpd.c b/drivers/gpu/drm/msm/dp/dp_hpd.c
index db98a1d431eb..40ca91c7dabe 100644
--- a/drivers/gpu/drm/msm/dp/dp_hpd.c
+++ b/drivers/gpu/drm/msm/dp/dp_hpd.c
@@ -7,6 +7,8 @@
 
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_print.h>
 
 #include "dp_hpd.h"
 
@@ -45,6 +47,24 @@ int dp_hpd_connect(struct dp_usbpd *dp_usbpd, bool hpd)
 	return rc;
 }
 
+static void dp_hpd_hpd_notify(struct dp_usbpd *dp_usbpd,
+			     enum drm_connector_status status)
+{
+	struct dp_hpd_private *hpd_priv = container_of(dp_usbpd, struct dp_hpd_private, dp_usbpd);
+
+	DRM_DEBUG_DP("status: %d connected: %d\n", status, dp_usbpd->connected);
+
+	if (!dp_usbpd->connected && status == connector_status_connected) {
+		dp_usbpd->connected = true;
+		hpd_priv->dp_cb->configure(hpd_priv->dev);
+	} else if (status != connector_status_connected) {
+		dp_usbpd->connected = false;
+		hpd_priv->dp_cb->disconnect(hpd_priv->dev);
+	} else {
+		hpd_priv->dp_cb->attention(hpd_priv->dev);
+	}
+}
+
 struct dp_usbpd *dp_hpd_get(struct device *dev, struct dp_usbpd_cb *cb)
 {
 	struct dp_hpd_private *dp_hpd;
@@ -62,6 +82,7 @@ struct dp_usbpd *dp_hpd_get(struct device *dev, struct dp_usbpd_cb *cb)
 	dp_hpd->dp_cb = cb;
 
 	dp_hpd->dp_usbpd.connect = dp_hpd_connect;
+	dp_hpd->dp_usbpd.hpd_notify = dp_hpd_hpd_notify;
 
 	return &dp_hpd->dp_usbpd;
 }
diff --git a/drivers/gpu/drm/msm/dp/dp_hpd.h b/drivers/gpu/drm/msm/dp/dp_hpd.h
index 8feec5aa5027..ff40790831a4 100644
--- a/drivers/gpu/drm/msm/dp/dp_hpd.h
+++ b/drivers/gpu/drm/msm/dp/dp_hpd.h
@@ -29,7 +29,9 @@ enum plug_orientation {
  * @hpd_irq: Change in the status since last message
  * @alt_mode_cfg_done: bool to specify alt mode status
  * @debug_en: bool to specify debug mode
+ * @connected: cable currently connected
  * @connect: simulate disconnect or connect for debug mode
+ * @hpd_notify: deliver oob event to the usbpd code
  */
 struct dp_usbpd {
 	enum plug_orientation orientation;
@@ -41,8 +43,11 @@ struct dp_usbpd {
 	bool hpd_irq;
 	bool alt_mode_cfg_done;
 	bool debug_en;
+	bool connected;
 
 	int (*connect)(struct dp_usbpd *dp_usbpd, bool hpd);
+	void (*hpd_notify)(struct dp_usbpd *dp_usbpd,
+			  enum drm_connector_status status);
 };
 
 /**
-- 
2.35.1