drm/connector: Add a drm_connector privacy-screen helper functions (v2)

Add 2 drm_connector privacy-screen helper functions:

1. drm_connector_attach_privacy_screen_provider(), this function creates
and attaches the standard privacy-screen properties and registers a
generic notifier for generating sysfs-connector-status-events on external
changes to the privacy-screen status.

2. drm_connector_update_privacy_screen(), update the privacy-screen's
sw_state if the connector has a privacy-screen.

Changes in v2:
- Do not update connector->state->privacy_screen_sw_state on
  atomic-commits.
- Change drm_connector_update_privacy_screen() to take drm_connector_state
  as argument instead of a full drm_atomic_state. This allows the helper
  to be called by drivers when they are enabling crtcs/encoders/connectors.
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005202322.700909-6-hdegoede@redhat.com

drivers/gpu/drm/drm_connector.c

@@ -28,6 +28,7 @@
 #include <drm/drm_print.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
+#include <drm/drm_privacy_screen_consumer.h>
 #include <drm/drm_sysfs.h>
 
 #include <linux/uaccess.h>
@@ -462,6 +463,11 @@ void drm_connector_cleanup(struct drm_connector *connector)
 		    DRM_CONNECTOR_REGISTERED))
 		drm_connector_unregister(connector);
 
+	if (connector->privacy_screen) {
+		drm_privacy_screen_put(connector->privacy_screen);
+		connector->privacy_screen = NULL;
+	}
+
 	if (connector->tile_group) {
 		drm_mode_put_tile_group(dev, connector->tile_group);
 		connector->tile_group = NULL;
@@ -543,6 +549,10 @@ int drm_connector_register(struct drm_connector *connector)
 	/* Let userspace know we have a new connector */
 	drm_sysfs_hotplug_event(connector->dev);
 
+	if (connector->privacy_screen)
+		drm_privacy_screen_register_notifier(connector->privacy_screen,
+					   &connector->privacy_screen_notifier);
+
 	mutex_lock(&connector_list_lock);
 	list_add_tail(&connector->global_connector_list_entry, &connector_list);
 	mutex_unlock(&connector_list_lock);
@@ -578,6 +588,11 @@ void drm_connector_unregister(struct drm_connector *connector)
 	list_del_init(&connector->global_connector_list_entry);
 	mutex_unlock(&connector_list_lock);
 
+	if (connector->privacy_screen)
+		drm_privacy_screen_unregister_notifier(
+					connector->privacy_screen,
+					&connector->privacy_screen_notifier);
+
 	if (connector->funcs->early_unregister)
 		connector->funcs->early_unregister(connector);
 
@@ -2466,6 +2481,93 @@ drm_connector_attach_privacy_screen_properties(struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_connector_attach_privacy_screen_properties);
 
+static void drm_connector_update_privacy_screen_properties(
+	struct drm_connector *connector, bool set_sw_state)
+{
+	enum drm_privacy_screen_status sw_state, hw_state;
+
+	drm_privacy_screen_get_state(connector->privacy_screen,
+				     &sw_state, &hw_state);
+
+	if (set_sw_state)
+		connector->state->privacy_screen_sw_state = sw_state;
+	drm_object_property_set_value(&connector->base,
+			connector->privacy_screen_hw_state_property, hw_state);
+}
+
+static int drm_connector_privacy_screen_notifier(
+	struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct drm_connector *connector =
+		container_of(nb, struct drm_connector, privacy_screen_notifier);
+	struct drm_device *dev = connector->dev;
+
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	drm_connector_update_privacy_screen_properties(connector, true);
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+	drm_sysfs_connector_status_event(connector,
+				connector->privacy_screen_sw_state_property);
+	drm_sysfs_connector_status_event(connector,
+				connector->privacy_screen_hw_state_property);
+
+	return NOTIFY_DONE;
+}
+
+/**
+ * drm_connector_attach_privacy_screen_provider - attach a privacy-screen to
+ *    the connector
+ * @connector: connector to attach the privacy-screen to
+ * @priv: drm_privacy_screen to attach
+ *
+ * Create and attach the standard privacy-screen properties and register
+ * a generic notifier for generating sysfs-connector-status-events
+ * on external changes to the privacy-screen status.
+ * This function takes ownership of the passed in drm_privacy_screen and will
+ * call drm_privacy_screen_put() on it when the connector is destroyed.
+ */
+void drm_connector_attach_privacy_screen_provider(
+	struct drm_connector *connector, struct drm_privacy_screen *priv)
+{
+	connector->privacy_screen = priv;
+	connector->privacy_screen_notifier.notifier_call =
+		drm_connector_privacy_screen_notifier;
+
+	drm_connector_create_privacy_screen_properties(connector);
+	drm_connector_update_privacy_screen_properties(connector, true);
+	drm_connector_attach_privacy_screen_properties(connector);
+}
+EXPORT_SYMBOL(drm_connector_attach_privacy_screen_provider);
+
+/**
+ * drm_connector_update_privacy_screen - update connector's privacy-screen sw-state
+ * @connector_state: connector-state to update the privacy-screen for
+ *
+ * This function calls drm_privacy_screen_set_sw_state() on the connector's
+ * privacy-screen.
+ *
+ * If the connector has no privacy-screen, then this is a no-op.
+ */
+void drm_connector_update_privacy_screen(const struct drm_connector_state *connector_state)
+{
+	struct drm_connector *connector = connector_state->connector;
+	int ret;
+
+	if (!connector->privacy_screen)
+		return;
+
+	ret = drm_privacy_screen_set_sw_state(connector->privacy_screen,
+					      connector_state->privacy_screen_sw_state);
+	if (ret) {
+		drm_err(connector->dev, "Error updating privacy-screen sw_state\n");
+		return;
+	}
+
+	/* The hw_state property value may have changed, update it. */
+	drm_connector_update_privacy_screen_properties(connector, false);
+}
+EXPORT_SYMBOL(drm_connector_update_privacy_screen);
+
 int drm_connector_set_obj_prop(struct drm_mode_object *obj,
 				    struct drm_property *property,
 				    uint64_t value)

include/drm/drm_connector.h

@@ -27,6 +27,7 @@
 #include <linux/llist.h>
 #include <linux/ctype.h>
 #include <linux/hdmi.h>
+#include <linux/notifier.h>
 #include <drm/drm_mode_object.h>
 #include <drm/drm_util.h>
 
@@ -40,6 +41,7 @@ struct drm_encoder;
 struct drm_property;
 struct drm_property_blob;
 struct drm_printer;
+struct drm_privacy_screen;
 struct edid;
 struct i2c_adapter;
 
@@ -1439,6 +1441,12 @@ struct drm_connector {
 	 */
 	struct drm_property *max_bpc_property;
 
+	/** @privacy_screen: drm_privacy_screen for this connector, or NULL. */
+	struct drm_privacy_screen *privacy_screen;
+
+	/** @privacy_screen_notifier: privacy-screen notifier_block */
+	struct notifier_block privacy_screen_notifier;
+
 	/**
 	 * @privacy_screen_sw_state_property: Optional atomic property for the
 	 * connector to control the integrated privacy screen.
@@ -1776,6 +1784,9 @@ int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
 					  int min, int max);
 void drm_connector_create_privacy_screen_properties(struct drm_connector *conn);
 void drm_connector_attach_privacy_screen_properties(struct drm_connector *conn);
+void drm_connector_attach_privacy_screen_provider(
+	struct drm_connector *connector, struct drm_privacy_screen *priv);
+void drm_connector_update_privacy_screen(const struct drm_connector_state *connector_state);
 
 /**
  * struct drm_tile_group - Tile group metadata