[PATCH v2 1/6] drm/connector: report IRQ_HPD events to drm_connector_oob_hotplug_event()

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

The DisplayPort standard defines a special kind of events called IRQ.
These events are used to notify DP Source about the events on the Sink
side. It is extremely important for DP MST handling, where the MST
events are reported through this IRQ.

In case of the USB-C DP AltMode there is no actual HPD pulse, but the
events are ported through the bits in the AltMode VDOs.

Extend the drm_connector_oob_hotplug_event() interface and report IRQ
events to the DisplayPort Sink drivers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/drm_connector.c          |  5 ++++-
 drivers/usb/typec/altmodes/displayport.c | 15 +++++++++++----
 include/drm/drm_connector.h              | 19 ++++++++++++++++++-
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 47dc53c4a738..edee9daccd51 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -3510,6 +3510,8 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
  * drm_connector_oob_hotplug_event - Report out-of-band hotplug event to connector
  * @connector_fwnode: fwnode_handle to report the event on
  * @status: hot plug detect logical state
+ * @extra_status: additional information provided by the sink without changing
+ * the HPD state (or in addition to such a change).
  *
  * On some hardware a hotplug event notification may come from outside the display
  * driver / device. An example of this is some USB Type-C setups where the hardware
@@ -3520,7 +3522,8 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
  * a drm_connector reference through calling drm_connector_find_by_fwnode().
  */
 void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
-				     enum drm_connector_status status)
+				     enum drm_connector_status status,
+				     enum drm_connector_status_extra extra_status)
 {
 	struct drm_connector *connector;
 
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index 35d9c3086990..7182a8e2e710 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -189,7 +189,9 @@ static int dp_altmode_status_update(struct dp_altmode *dp)
 	} else {
 		drm_connector_oob_hotplug_event(dp->connector_fwnode,
 						hpd ? connector_status_connected :
-						      connector_status_disconnected);
+						      connector_status_disconnected,
+						(hpd && irq_hpd) ? DRM_CONNECTOR_DP_IRQ_HPD :
+								   DRM_CONNECTOR_NO_EXTRA_STATUS);
 		dp->hpd = hpd;
 		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
 		if (hpd && irq_hpd) {
@@ -212,7 +214,10 @@ static int dp_altmode_configured(struct dp_altmode *dp)
 	 */
 	if (dp->pending_hpd) {
 		drm_connector_oob_hotplug_event(dp->connector_fwnode,
-						connector_status_connected);
+						connector_status_connected,
+						dp->pending_irq_hpd ?
+						DRM_CONNECTOR_DP_IRQ_HPD :
+						DRM_CONNECTOR_NO_EXTRA_STATUS);
 		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
 		dp->pending_hpd = false;
 		if (dp->pending_irq_hpd) {
@@ -397,7 +402,8 @@ static int dp_altmode_vdm(struct typec_altmode *alt,
 			dp->data.conf = 0;
 			if (dp->hpd) {
 				drm_connector_oob_hotplug_event(dp->connector_fwnode,
-								connector_status_disconnected);
+								connector_status_disconnected,
+								DRM_CONNECTOR_NO_EXTRA_STATUS);
 				dp->hpd = false;
 				sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
 			}
@@ -827,7 +833,8 @@ void dp_altmode_remove(struct typec_altmode *alt)
 
 	if (dp->connector_fwnode) {
 		drm_connector_oob_hotplug_event(dp->connector_fwnode,
-						connector_status_disconnected);
+						connector_status_disconnected,
+						DRM_CONNECTOR_NO_EXTRA_STATUS);
 
 		fwnode_handle_put(dp->connector_fwnode);
 	}
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index f83f28cae207..e05197e970d3 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -91,6 +91,22 @@ enum drm_connector_status {
 	connector_status_unknown = 3,
 };
 
+/**
+ * enum drm_connector_status_extra - additional events sent by the sink /
+ * display together or in replacement of the HPD status changes.
+ */
+enum drm_connector_status_extra {
+	/**
+	 * @DRM_CONNECTOR_NO_EXTRA_STATUS: No additional status reported.
+	 */
+	DRM_CONNECTOR_NO_EXTRA_STATUS,
+	/**
+	 * @DRM_CONNECTOR_DP_IRQ_HPD: DisplayPort Sink has sent the
+	 * IRQ_HPD (either by the HPD short pulse or via the AltMode event).
+	 */
+	DRM_CONNECTOR_DP_IRQ_HPD,
+};
+
 /**
  * enum drm_connector_registration_state - userspace registration status for
  * a &drm_connector
@@ -2521,7 +2537,8 @@ drm_connector_is_unregistered(struct drm_connector *connector)
 }
 
 void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
-				     enum drm_connector_status status);
+				     enum drm_connector_status status,
+				     enum drm_connector_status_extra extra_status);
 const char *drm_get_connector_type_name(unsigned int connector_type);
 const char *drm_get_connector_status_name(enum drm_connector_status status);
 const char *drm_get_subpixel_order_name(enum subpixel_order order);

-- 
2.47.3