[PATCH v4 1/7] usb: typec: Add default HPD device when register DisplayPort altmode

[Chaoyi Chen <kernel@xxxxxxxxxx>]

From: Chaoyi Chen <chaoyi.chen@xxxxxxxxxxxxxx>

Add default DRM AUX HPD bridge device when register DisplayPort
altmode. That makes it redundant for each Type-C driver to implement
a similar registration process in embedded scenarios.

Signed-off-by: Chaoyi Chen <chaoyi.chen@xxxxxxxxxxxxxx>
---
 drivers/usb/typec/altmodes/displayport.c | 27 ++++++++++++++++++++++++
 drivers/usb/typec/altmodes/displayport.h |  2 ++
 drivers/usb/typec/class.c                |  8 +++++++
 include/linux/usb/typec_altmode.h        |  2 ++
 4 files changed, 39 insertions(+)

diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index 1dcb77faf85d..e026dc6e5430 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -14,6 +14,7 @@
 #include <linux/property.h>
 #include <linux/usb/pd_vdo.h>
 #include <linux/usb/typec_dp.h>
+#include <drm/bridge/aux-bridge.h>
 #include <drm/drm_connector.h>
 #include "displayport.h"
 
@@ -182,6 +183,10 @@ static int dp_altmode_status_update(struct dp_altmode *dp)
 				dp->pending_irq_hpd = true;
 		}
 	} else {
+		if (dp->port->hpd_dev)
+			drm_aux_hpd_bridge_notify(dp->port->hpd_dev,
+						  hpd ? connector_status_connected :
+							connector_status_disconnected);
 		drm_connector_oob_hotplug_event(dp->connector_fwnode,
 						hpd ? connector_status_connected :
 						      connector_status_disconnected);
@@ -206,6 +211,9 @@ static int dp_altmode_configured(struct dp_altmode *dp)
 	 * configuration is complete to signal HPD.
 	 */
 	if (dp->pending_hpd) {
+		if (dp->port->hpd_dev)
+			drm_aux_hpd_bridge_notify(dp->port->hpd_dev,
+						  connector_status_connected);
 		drm_connector_oob_hotplug_event(dp->connector_fwnode,
 						connector_status_connected);
 		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
@@ -391,6 +399,9 @@ static int dp_altmode_vdm(struct typec_altmode *alt,
 			dp->data.status = 0;
 			dp->data.conf = 0;
 			if (dp->hpd) {
+				if (dp->port->hpd_dev)
+					drm_aux_hpd_bridge_notify(dp->port->hpd_dev,
+								  connector_status_disconnected);
 				drm_connector_oob_hotplug_event(dp->connector_fwnode,
 								connector_status_disconnected);
 				dp->hpd = false;
@@ -751,6 +762,18 @@ static const struct attribute_group *displayport_groups[] = {
 	NULL,
 };
 
+void dp_altmode_hpd_device_register(struct typec_altmode *alt)
+{
+	if (alt->svid != USB_TYPEC_DP_SID)
+		return;
+
+	alt->hpd_dev = drm_dp_hpd_bridge_register(alt->dev.parent->parent,
+						  dev_of_node(alt->dev.parent->parent));
+	if (IS_ERR(alt->hpd_dev))
+		alt->hpd_dev = NULL;
+}
+EXPORT_SYMBOL_GPL(dp_altmode_hpd_device_register);
+
 int dp_altmode_probe(struct typec_altmode *alt)
 {
 	const struct typec_altmode *port = typec_altmode_get_partner(alt);
@@ -812,6 +835,10 @@ void dp_altmode_remove(struct typec_altmode *alt)
 	cancel_work_sync(&dp->work);
 	typec_altmode_put_plug(dp->plug_prime);
 
+	if (dp->port->hpd_dev)
+		drm_aux_hpd_bridge_notify(dp->port->hpd_dev,
+					  connector_status_disconnected);
+
 	if (dp->connector_fwnode) {
 		drm_connector_oob_hotplug_event(dp->connector_fwnode,
 						connector_status_disconnected);
diff --git a/drivers/usb/typec/altmodes/displayport.h b/drivers/usb/typec/altmodes/displayport.h
index e120364da9fd..9f3483ec10fb 100644
--- a/drivers/usb/typec/altmodes/displayport.h
+++ b/drivers/usb/typec/altmodes/displayport.h
@@ -2,7 +2,9 @@
 #if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
 int dp_altmode_probe(struct typec_altmode *alt);
 void dp_altmode_remove(struct typec_altmode *alt);
+void dp_altmode_hpd_device_register(struct typec_altmode *alt);
 #else
 int dp_altmode_probe(struct typec_altmode *alt) { return -ENOTSUPP; }
 void dp_altmode_remove(struct typec_altmode *alt) { }
+void dp_altmode_hpd_device_register(struct typec_altmode *alt) { }
 #endif /* CONFIG_TYPEC_DP_ALTMODE */
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 67a533e35150..95732b6d9a95 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -15,6 +15,7 @@
 #include <linux/usb/typec_mux.h>
 #include <linux/usb/typec_retimer.h>
 #include <linux/usb.h>
+#include "altmodes/displayport.h"
 
 #include "bus.h"
 #include "class.h"
@@ -600,6 +601,13 @@ typec_register_altmode(struct device *parent,
 		return ERR_PTR(ret);
 	}
 
+	/*
+	 * It is too late to register the HPD device when the DisplayPort
+	 * altmode device becomes ready. If the current altmode is DP,
+	 * register a static HPD device.
+	 */
+	dp_altmode_hpd_device_register(&alt->adev);
+
 	return &alt->adev;
 }
 
diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
index b3c0866ea70f..acb0af1b9d5d 100644
--- a/include/linux/usb/typec_altmode.h
+++ b/include/linux/usb/typec_altmode.h
@@ -21,6 +21,7 @@ struct typec_altmode_ops;
  * @desc: Optional human readable description of the mode
  * @ops: Operations vector from the driver
  * @cable_ops: Cable operations vector from the driver.
+ * @hpd_dev: HPD device for DisplayPort
  */
 struct typec_altmode {
 	struct device			dev;
@@ -32,6 +33,7 @@ struct typec_altmode {
 	char				*desc;
 	const struct typec_altmode_ops	*ops;
 	const struct typec_cable_ops	*cable_ops;
+	struct device			*hpd_dev;
 };
 
 #define to_typec_altmode(d) container_of(d, struct typec_altmode, dev)
-- 
2.49.0