[PATCH v4 5/5] drm/msm/dp: Implement hpd_notify()

[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>
---

Changes since v3:
- Implements hpd_notify instead of oob_hotplug_event
- Rebased on new cleanup patch from Dmitry
- Set hpd_state to ST_MAINLINK_READY when dp_display_usbpd_configure() succeeds

 drivers/gpu/drm/msm/dp/dp_display.c | 26 ++++++++++++++++++++++++++
 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 ++
 4 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index b447446d75e9..080294ac6144 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -83,6 +83,8 @@ struct dp_display_private {
 	bool hpd_irq_on;
 	bool audio_supported;
 
+	bool connected;
+
 	struct drm_device *drm_dev;
 	struct platform_device *pdev;
 	struct dentry *root;
@@ -1271,6 +1273,7 @@ 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;
@@ -1760,3 +1763,26 @@ 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);
+	int ret;
+
+	drm_dbg_dp(dp_display->drm_dev, "status: %d connected: %d\n", status, dp_display->connected);
+
+	if (!dp_display->connected && status == connector_status_connected) {
+		dp_display->connected = true;
+		ret = dp_display_usbpd_configure(dp_display);
+		if (!ret)
+			dp_display->hpd_state = ST_MAINLINK_READY;
+	} else if (status != connector_status_connected) {
+		dp_display->connected = false;
+		dp_display_notify_disconnect(dp_display);
+	} else {
+		dp_display_usbpd_attention(dp_display);
+	}
+}
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_ */
-- 
2.35.1