drm/vc4: txp: add implementation of the missing connector reset custom function

In the previous commit, we added a rotation parameter to be used in the
connector, but because we are still using the default reset function
without implementing a custom reset function to properly initialize it,
the rotation variable remains NULL until it is initialized directly
in userspace.

To prevent this, you must implement a custom reset function that properly
initializes the rotation parameter.

Fixes: 30c7044 ("drm: Add a rotation parameter to connectors.")
Signed-off-by: Jeongjun Park <[email protected]>

Author: name2965

drivers/gpu/drm/vc4/vc4_drv.h

@@ -1087,6 +1087,7 @@ extern struct platform_driver vc4_vec_driver;
 
 /* vc4_txp.c */
 extern struct platform_driver vc4_txp_driver;
+void vc4_txp_connector_reset(struct drm_connector *connector);
 
 /* vc4_irq.c */
 void vc4_irq_enable(struct drm_device *dev);

drivers/gpu/drm/vc4/vc4_txp.c

@@ -390,11 +390,34 @@ vc4_txp_connector_detect(struct drm_connector *connector, bool force)
 	return connector_status_connected;
 }
 
+void vc4_txp_connector_reset(struct drm_connector *connector)
+{
+	struct drm_connector_state *state = connector->state;
+	uint64_t rotation = DRM_MODE_ROTATE_0;
+
+	if (connector->state)
+		__drm_atomic_helper_connector_destroy_state(connector->state);
+
+	kfree(state);
+
+	state = kzalloc(sizeof(struct drm_connector_state), GFP_KERNEL);
+
+	if (state) {
+		if (connector->rotation_property)
+			drm_object_property_get_default_value(&connector->base,
+								   connector->rotation_property,
+								   &rotation);
+		state->rotation = rotation;
+	}
+
+	__drm_atomic_helper_connector_reset(connector, state);
+}
+
 static const struct drm_connector_funcs vc4_txp_connector_funcs = {
 	.detect = vc4_txp_connector_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.destroy = drm_connector_cleanup,
-	.reset = drm_atomic_helper_connector_reset,
+	.reset = vc4_txp_connector_reset,
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };